U.S. patent application number 16/480569 was filed with the patent office on 2020-09-03 for genetically optimised microorganism for producing molecules of interest.
The applicant listed for this patent is ENOBRAQ. Invention is credited to Cedric BOISART, Nicolas MORIN.
Application Number | 20200277592 16/480569 |
Document ID | / |
Family ID | 1000004871394 |
Filed Date | 2020-09-03 |
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United States Patent
Application |
20200277592 |
Kind Code |
A1 |
BOISART; Cedric ; et
al. |
September 3, 2020 |
GENETICALLY OPTIMISED MICROORGANISM FOR PRODUCING MOLECULES OF
INTEREST
Abstract
The invention concerns a genetically modified microorganism
expressing a functional type I or II RuBisCO enzyme and a
functional phosphoribulokinase (PRK), and in which the glycolysis
pathway is at least partially inhibited, said microorganism being
genetically modified so as to produce an exogenous molecule and/or
to overproduce an endogenous molecule. According to the invention,
the oxidative branch of the pentose phosphate pathway may also be
at least partially inhibited. The invention also concerns the use
of such a genetically modified microorganism for the production or
overproduction of a molecule of interest and processes for the
synthesis or bioconversion of molecules of interest.
Inventors: |
BOISART; Cedric; (Belberaud,
FR) ; MORIN; Nicolas; (Toulouse, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ENOBRAQ |
RAMONVILLE SAINT- AGNE |
|
FR |
|
|
Family ID: |
1000004871394 |
Appl. No.: |
16/480569 |
Filed: |
January 26, 2018 |
PCT Filed: |
January 26, 2018 |
PCT NO: |
PCT/EP2018/052005 |
371 Date: |
July 24, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C12P 7/625 20130101;
C12P 7/42 20130101; C12N 9/88 20130101; C12P 13/14 20130101; C12Y
207/01019 20130101; C12N 9/1205 20130101; C12Y 401/01039 20130101;
C12P 13/001 20130101; C12P 7/62 20130101 |
International
Class: |
C12N 9/88 20060101
C12N009/88; C12N 9/12 20060101 C12N009/12; C12P 7/62 20060101
C12P007/62; C12P 13/14 20060101 C12P013/14; C12P 13/00 20060101
C12P013/00; C12P 7/42 20060101 C12P007/42 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 27, 2017 |
FR |
1750694 |
Claims
1. A genetically modified microorganism for the production of an
exogenous molecule of interest and/or to overproduce an endogenous
molecule of interest, other than a RuBisCO or phosphoribulokinase
enzyme, said microorganism expressing a functional RuBisCO enzyme
and a functional phosphoribulokinase (PRK), and in which the
glycolysis pathway is at least partially inhibited, upstream of the
production of 1,3-biphospho-D-glycerate (1,3-BPG) or upstream of
the production of 3-phosphoglycerate (3PG), and downstream of the
production of glyceraldehyde-3-phosphate (G3P), wherein said
microorganism is genetically modified so as to produce the
exogenous molecule of interest and/or to overproduce the endogenous
molecule of interest, other than a RuBisCO or phosphoribulokinase
enzyme.
2. The genetically modified microorganism according to claim 1,
wherein the oxidative branch of the pentose phosphate pathway is
also at least partially inhibited.
3. The genetically modified microorganism according to claim 1,
wherein said microorganism is genetically modified to express a
recombinant RuBisCO enzyme and/or PRK.
4. The genetically modified microorganism according to claim 2,
wherein said microorganism is genetically modified to inhibit the
oxidative branch of the pentose phosphate pathway upstream of
ribulose-5-phosphate production.
5. The genetically modified microorganism according to claim 1,
wherein the exogenous molecule and/or the endogenous molecule is
selected from amino acids, peptides, proteins, vitamins, sterols,
flavonoids, terpenes, terpenoids, fatty acids, polyols and organic
acids.
6. The genetically modified microorganism according to claim 1,
wherein said microorganism is a eukaryotic cell or a prokaryotic
cell.
7. The genetically modified microorganism according to claim 1,
wherein the expression of the gene encoding glyceraldehyde
3-phosphate dehydrogenase is at least partially inhibited.
8. The genetically modified microorganism according to claim 1,
wherein the expression of the gene encoding phosphoglycerate kinase
is at least partially inhibited.
9. The genetically modified microorganism according to claim 7,
wherein the expression of the gene encoding glucose-6-phosphate
dehydrogenase or 6-phosphogluconolactonase or 6-phosphogluconate
dehydrogenase is at least partially inhibited.
10. The genetically modified microorganism according to claim 1,
wherein said microorganism is a yeast of the genus Saccharomyces
cerevisiae genetically modified to express a functional type I or
II RuBisCO and a functional phosphoribulokinase (PRK), and in which
the expression of the TDH1, TDH2 and/or TDH3 gene is at least
partially inhibited.
11. The genetically modified microorganism according to claim 1,
wherein said microorganism is a Saccharomyces cerevisiae yeast
genetically modified to express a functional type I or II RuBisCO
and a functional phosphoribulokinase (PRK), and in which the
expression of the PGK1 gene is at least partially inhibited.
12. The genetically modified microorganism according to claim 10,
wherein the expression of the ZWF1 gene is at least partially
inhibited.
13. The genetically modified microorganism according to claim 1,
wherein said microorganism is a filamentous fungus of the genus
Aspergillus genetically modified to express a functional type I or
II RuBisCO and a functional phosphoribulokinase (PRK), and in which
the expression of the pgk and gsdA genes is at least partially
inhibited.
14. The genetically modified microorganism according to claim 1,
wherein said microorganism is an E. coli bacterium genetically
modified to express a functional type I or II RuBisCO and a
functional phosphoribulokinase (PRK), and in which the expression
of the gapA and/or pgk gene, and optionally the zwf gene, is at
least partially inhibited.
15.-16. (canceled)
17. A biotechnological process for producing at least one molecule
of interest, wherein it comprises a step of culturing a genetically
modified microorganism as defined in claim 1, under conditions
allowing the synthesis or bioconversion by said microorganism of
said molecule of interest, and optionally a step of recovering
and/or purifying said molecule of interest.
18. The biotechnological process according to claim 17, wherein the
molecule of interest is selected from amino acids, peptides,
proteins, vitamins, sterols, flavonoids, terpenes, terpenoids,
fatty acids, polyols and organic acids.
19. The biotechnological process according to claim 17, wherein the
molecule of interest is selected glutamate, citrate, itaconate or
GABA.
20. The biotechnological process according to claim 17, wherein the
microorganism is genetically modified to express at least one
enzyme involved in the bioconversion or synthesis of said molecule
of interest.
21. The biotechnological process according to claim 17, wherein the
microorganism is genetically modified to at least partially inhibit
an enzyme involved in the degradation of said molecule of
interest.
22. A process for producing a molecule of interest comprising (i)
inserting at least one sequence encoding an enzyme involved in the
synthesis or bioconversion of said molecule of interest into a
recombinant microorganism as defined in claim 1, (ii) culturing
said microorganism under conditions allowing expression of said
enzyme and optionally (iii) recovering and/or purifying said
molecule of interest.
23. A process for producing a molecule of interest comprising (i)
inhibiting the expression of at least one gene encoding an enzyme
involved in the degradation of said molecule of interest in a
recombinant microorganism as defined in claim 1, (ii) culturing
said microorganism under conditions allowing expression of said
enzyme and optionally (iii) recovering and/or purifying said
molecule of interest.
24. The genetically modified microorganism of claim 1, wherein said
microorganism is a eukaryotic cell selected from yeasts, fungi and
microalgae.
25. The genetically modified microorganism of claim 1, wherein said
microorganism is a bacterium.
Description
FIELD OF THE INVENTION
[0001] The invention concerns a genetically modified microorganism,
capable of using carbon dioxide as an at least partial carbon
source, for the production of molecules of interest. More
specifically, the invention relates to a microorganism in which at
least the glycolysis pathway is at least partially inhibited. The
invention also relates to processes for the production of at least
one molecule of interest using such a microorganism.
STATE OF THE ART
[0002] Over the past few years, a number of microbiological
processes have been developed to enable the production of molecules
of interest in large quantities.
[0003] For example, fermentation processes are used to produce
molecules by a microorganism from a fermentable carbon source, such
as glucose.
[0004] Bioconversion processes have also been developed to allow a
microorganism to convert a co-substrate, not assimilable by said
microorganism, into a molecule of interest. Here again, a carbon
source is required, not for the actual production of the molecule
of interest, but for the production of cofactors, and more
particularly NADPH, that may be necessary for bioconversion. In
general, the production yield of such microbiological processes is
low, mainly due to the need for cofactors and the difficulty of
balancing redox metabolic reactions. There is also the problem of
the cost price of such molecules, since a source of carbon
assimilable by the microorganism is still necessary. In other
words, currently, in order to produce a molecule of interest with a
microbiological process, it is necessary to provide a molecule
(glucose, or other), certainly of lower industrial value, but which
is sufficient to make the production of certain molecules not
economically attractive.
[0005] At the same time, carbon dioxide (CO.sub.2), whose emissions
into the atmosphere are constantly increasing, is used little, if
at all, in current microbiological processes, while its consumption
by microorganisms for the production of molecules of interest would
not only reduce production costs, but also address certain
ecological issues.
[0006] There is therefore still a need for microbiological
processes to enable the production of molecules of interest in
large quantities and with lower cost prices than with current
processes.
SUMMARY OF THE INVENTION
[0007] The advantage of using non-photosynthetic microorganisms
genetically modified to capture CO.sub.2 and use it as the main
carbon source, in the same way as plants and photosynthetic
microorganisms, has already been demonstrated. For example,
microorganisms modified to express a functional RuBisCO
(ribulose-1,5-bisphosphate carboxylase/oxygenase--EC 4.1.1.39) and
a functional PRK (phosphoribulokinase--EC 2.7.1.19) to reproduce a
partial Calvin cycle and convert ribulose-5-phosphate into two
3-phosphoglycerate molecules by capturing a carbon dioxide molecule
have been developed.
[0008] By working on the solutions provided by the Calvin cycle to
produce molecules of interest using CO.sub.2 as carbon source, the
inventors discovered that it is possible to increase the production
yield of molecules of interest by coupling part of the Calvin cycle
(PRK/RuBisCO) to at least partial inhibition of glycolysis. The
inventors have also discovered that it is possible to increase the
consumption of exogenous CO.sub.2 during the production of
molecules of interest, by also at least partially inhibiting the
oxidative branch of the pentose phosphate pathway. The
microorganisms thus developed make it possible to produce on a
large scale and with an industrially attractive yield a large
number of molecules of interest, such as amino acids, organic
acids, terpenes, terpenoids, peptides, fatty acids, polyols,
etc.
[0009] The invention thus relates to a genetically modified
microorganism expressing a functional RuBisCO enzyme and a
functional phosphoribulokinase (PRK), and in which the glycolysis
pathway is at least partially inhibited, said microorganism being
genetically modified so as to produce an exogenous molecule of
interest and/or to overproduce an endogenous molecule of interest,
other than a RuBisCO or phosphoribulokinase enzyme.
[0010] In one particular embodiment, the genetically modified
microorganism has an oxidative branch of the pentose phosphate
pathway that is also at least partially inhibited.
[0011] The invention also concerns the use of a genetically
modified microorganism according to the invention, for the
production or overproduction of a molecule of interest,
preferentially selected from amino acids, peptides, proteins,
vitamins, sterols, flavonoids, terpenes, terpenoids, fatty acids,
polyols and organic acids.
[0012] The present invention also concerns a biotechnological
process for producing or overproducing at least one molecule of
interest, characterized in that it comprises a step of culturing a
genetically modified microorganism according to the invention,
under conditions allowing the synthesis or bioconversion, by said
microorganism, of said molecule of interest, and optionally a step
of recovering and/or purifying said molecule of interest.
[0013] It also concerns a process for producing a molecule of
interest comprising (i) inserting at least one sequence encoding an
enzyme involved in the synthesis or bioconversion of said molecule
of interest into a recombinant microorganism according to the
invention, (ii) culturing said microorganism under conditions
allowing the expression of said enzyme and optionally (iii)
recovering and/or purifying said molecule of interest.
DESCRIPTION OF THE FIGURES
[0014] FIG. 1: General diagram of glycolysis, the pentose phosphate
pathway and the Entner-Doudoroff pathway;
[0015] FIG. 2: Schematic representation of inhibition of the
glycolysis pathway, according to the invention;
[0016] FIG. 3: Schematic representation of inhibition of the
glycolysis pathway, combined with inhibition of the oxidative
branch of the pentose phosphate pathway, according to the
invention.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0017] The terms "recombinant microorganism", "modified
microorganism" and "recombinant host cell" are used herein
interchangeably and refer to microorganisms that have been
genetically modified to express or overexpress endogenous
nucleotide sequences, to express heterologous nucleotide sequences,
or that have an altered expression of an endogenous gene.
"Alteration" means that the expression of the gene, or level of an
RNA molecule or equivalent RNA molecules encoding one or more
polypeptides or polypeptide subunits, or the activity of one or
more polypeptides or polypeptide subunits is regulated, so that the
expression, the level or the activity is higher or lower than that
observed in the absence of modification.
[0018] It is understood that the terms "recombinant microorganism",
"modified microorganism" and "recombinant host cell" refer not only
to the particular recombinant microorganism but to the progeny or
the potential progeny of such a microorganism. As some
modifications may occur in subsequent generations, due to mutation
or environmental influences, these offspring may not be identical
to the mother cell, but they are still understood within the scope
of the term as used here.
[0019] In the context of the invention, an at least partially
"inhibited" or "inactivated" metabolic pathway refers to an altered
metabolic pathway that can no longer function properly in the
microorganism considered, compared with the same wild-type
microorganism (not genetically modified to inhibit said metabolic
pathway). In particular, the metabolic pathway may be interrupted,
leading to the accumulation of an intermediate metabolite. Such an
interruption may be achieved, for example, by inhibiting the enzyme
necessary for the degradation of an intermediate metabolite of the
metabolic pathway considered and/or by inhibiting the expression of
the gene encoding that enzyme. The metabolic pathway may also be
attenuated, i.e. slowed down. Such attenuation may be achieved, for
example, by partially inhibiting one or more enzymes involved in
the metabolic pathway considered and/or partially inhibiting the
expression of a gene encoding at least one of these enzymes and/or
by exploiting the cofactors required for certain reactions. The
expression "at least partially inhibited metabolic pathway" means
that the level of the metabolic pathway considered is reduced by at
least 20%, more preferentially at least 30%, 40%, 50%, or more,
compared with the level in a wild-type microorganism. The reduction
may be greater, and in particular be at least greater than 60%,
70%, 80%, 90%. According to the invention, inhibition may be total,
in the sense that the metabolic pathway considered is no longer
used at all by said microorganism. According to the invention, such
inhibition may be temporary or permanent.
[0020] According to the invention, "inhibition of gene expression"
means that the gene is no longer expressed in the microorganism
considered or that its expression is reduced, compared with
wild-type microorganisms (not genetically modified to inhibit gene
expression), leading to the absence of production of the
corresponding protein or to a significant decrease in its
production, and in particular to a decrease of more than 20%, more
preferentially 30%, 40%, 50%, 60%, 70%, 80%, 90%. In one
embodiment, inhibition can be total, i.e. the protein encoded by
said gene is no longer produced at all. Inhibition of gene
expression can be achieved by deletion, mutation, insertion and/or
substitution of one or more nucleotides in the gene considered.
Preferentially, inhibition of gene expression is achieved by total
deletion of the corresponding nucleotide sequence. According to the
invention, any method of gene inhibition, known per se by the
skilled person and applicable to a microorganism, may be used. For
example, inhibition of gene expression can be achieved by
homologous recombination (Datsenko et al., Proc Natl Acad Sci USA.
2000; 97:6640-5; Lodish et al., Molecular Cell Biology 4.sup.th ed.
2000. W. H. Freeman and Company. ISBN 0-7167-3136-3); random or
directed mutagenesis to modify gene expression and/or encoded
protein activity (Thomas et al., Cell. 1987; 51:503-12);
modification of a promoter sequence of the gene to alter its
expression (Kaufmann et al., Methods Mol Biol. 2011; 765:275-94.
doi: 10.1007/978-1-61779-197-0_16); targeting induced local lesions
in genomes (TILLING); conjugation, etc. Another particular approach
is gene inactivation by insertion of a foreign sequence, for
example by transposon mutagenesis using mobile genetic elements
(transposons), of natural or artificial origin. According to
another preferred embodiment, inhibition of gene expression is
achieved by knock-out techniques. Inhibition of gene expression can
also be achieved by extinguishing the gene using interfering,
ribozyme or antisense RNA (Daneholt, 2006. Nobel Prize in
Physiology or Medicine). In the context of the present invention,
the term "interfering RNA" or "iRNA" refers to any iRNA molecule
(for example single-stranded RNA or double-stranded RNA) that can
block the expression of a target gene and/or facilitate the
degradation of the corresponding mRNA. Gene inhibition can also be
achieved by genome editing methods that allow direct genetic
modification of a given genome, through the use of zinc finger
nucleases (Kim et al., PNAS; 93: 1156-1160), transcription
activator-like effector nucleases, or "TALEN" (Ousterout et al.,
Methods Mol Biol. 2016; 1338:27-42. doi:
10.1007/978-1-4939-2932-0_3), a system combining Cas9 nucleases
with clustered regularly interspaced short palindromic repeats, or
"CRISPR" (Mali et al., Nat Methods. 2013 October; 10(10):957-63.
doi: 10.1038/nmeth.2649), or meganucleases (Daboussi et al.,
Nucleic Acids Res. 2012. 40:6367-79). Inhibition of gene expression
can also be achieved by inactivating the protein encoded by said
gene.
[0021] In the context of the invention, "NADPH-dependent" or
"NADPH-consuming" biosynthesis or bioconversion means all
biosynthesis or bioconversion pathways in which one or more enzymes
require the concomitant supply of electrons obtained by the
oxidation of an NADPH cofactor. "NADPH-dependent" biosynthesis or
bioconversion pathways notably concern the synthesis of amino acids
(e.g. arginine, lysine, methionine, threonine, proline, glutamate,
homoserine, isoleucine, valine) .gamma.-aminobutyric acid,
terpenoids and terpenes (e.g. farnesene), vitamins and precursors
(e.g. pantoate, pantothenate, transneurosporene, phylloquinone,
tocopherols), sterols (e.g. squalene, cholesterol, testosterone,
progesterone, cortisone), flavonoids (e.g. frambinone, vestinone),
organic acids (e.g. citric acid, succinic acid, oxalic acid,
itaconic acid, coumaric acid, 3-hydroxypropionic acid), polyols
(e.g. sorbitol, xylitol, glycerol), polyamines (e.g. spermidine),
aromatic molecules from stereospecific hydroxylation, via an
NADP-dependent cytochrome p450 (e.g. phenylpropanoids, terpenes,
lipids, tannins, fragrances, hormones).
[0022] The term "exogenous" as used here in reference to various
molecules (nucleotide sequences, peptides, enzymes, etc.) refers to
molecules that are not normally or naturally found in and/or
produced by the microorganism considered. Conversely, the term
"endogenous" or "native" refers to various molecules (nucleotide
sequences, peptides, enzymes, etc.), designating molecules that are
normally or naturally found in and/or produced by the microorganism
considered.
[0023] Microorganisms
[0024] The invention proposes genetically modified microorganisms
for the production of a molecule of interest, endogenous or
exogenous.
[0025] "Genetically modified" microorganism means that the genome
of the microorganism has been modified to incorporate a nucleic
sequence encoding an enzyme involved in the biosynthesis or
bioconversion pathway of a molecule of interest, or encoding a
biologically active fragment thereof. Said nucleic sequence may
have been introduced into the genome of said microorganism or one
of its ancestors, by any suitable molecular cloning method. In the
context of the invention, the genome of the microorganism refers to
all genetic material contained in the microorganism, including
extrachromosomal genetic material contained, for example, in
plasmids, episomes, synthetic chromosomes, etc. The introduced
nucleic sequence may be a heterologous sequence, i.e. one that does
not naturally exist in said microorganism, or a homologous
sequence. Advantageously, a transcriptional unit with the nucleic
sequence of interest is introduced into the genome of the
microorganism, under the control of one or more promoters. Such a
transcriptional unit also includes, advantageously, the usual
sequences such as transcriptional terminators, and, if necessary,
other transcription regulatory elements.
[0026] Promoters usable in the present invention include
constitutive promoters, i.e. promoters that are active in most
cellular states and environmental conditions, as well as inducible
promoters that are activated or suppressed by exogenous physical or
chemical stimuli, and therefore induce a variable state of
expression depending on the presence or absence of these stimuli.
For example, when the microorganism is a yeast, it is possible to
use a constitutive promoter, such as that of a gene among TEF1,
TDH3, PGI1, PGK, ADH1. Examples of inducible promoters that can be
used in yeast are tetO-2, GAL10, GAL10-CYC1, PHO5.
[0027] In general, the genetically modified microorganism according
to the invention has the following features: [0028] Expression of a
functional RuBisCO (EC 4.1.1.39); [0029] Expression of a functional
PRK (EC 2.7.1.19); [0030] At least partial inhibition of
glycolysis; and [0031] Expression of at least one gene involved in
the synthesis and/or bioconversion of a molecule of interest,
and/or inhibition of at least one gene encoding activity competing
with the synthesis and/or bioconversion of a molecule of
interest.
[0032] According to the invention, any microorganism can be used.
Preferentially the microorganism is a eukaryotic cell,
preferentially selected from yeasts, fungi, microalgae or a
prokaryotic cell, preferentially a bacterium or cyanobacterium.
[0033] In one embodiment, the genetically modified microorganism
according to the invention is a yeast, preferentially selected from
among the ascomycetes (Spermophthoraceae and Saccharomycetaceae),
basidiomycetes (Leucosporidium, Rhodosporidium, Sporidiobolus,
Filobasidium, and Filobasidiella) and deuteromycetes yeasts
belonging to Fungi imperfecti (Sporobolomycetaceae, and
Cryptococcaceae). Preferentially, the genetically modified yeast
according to the invention belongs to the genus Pichia,
Kluyveromyces, Saccharomyces, Schizosaccharomyces, Candida,
Lipomyces, Rhodotorula, Rhodosporidium, Yarrowia, or Debaryomyces.
More preferentially, the genetically modified yeast according to
the invention is selected from Pichia pastoris, Kluyveromyces
lactis, Kluyveromyces marxianus, Saccharomyces cerevisiae,
Saccharomyces carlsbergensis, Saccharomyces diastaticus,
Saccharomyces douglasii, Saccharomyces kluyveri, Saccharomyces
norbensis, Saccharomyces oviformis, Schizosaccharomyces pombe,
Candida albicans, Candida tropicalis, Rhodotorula glutinis,
Rhodosporidium toruloides, Yarrowia lipolytica, Debaryomyces
hansenii and Lipomyces starkeyi.
[0034] In another embodiment, the genetically modified
microorganism according to the invention is a fungus, and more
particularly a "filamentous" fungus. In the context of the
invention, "filamentous fungi" refers to all filamentous forms of
subdivision Eumycotina. For example, the genetically modified
fungus according to the invention belongs to the genus Aspergillus,
Trichoderma, Neurospora, Podospora, Endothia, Mucor, Cochliobolus
or Pyricularia. Preferentially, the genetically modified fungus
according to the invention is selected from Aspergillus nidulans,
Aspergillus niger, Aspergillus awomari, Aspergillus oryzae,
Aspergillus terreus, Neurospora crassa, Trichoderma reesei, and
Trichoderma viride.
[0035] In another embodiment, the genetically modified
microorganism according to the invention is a microalga. In the
context of the invention, "microalga" refers to all eukaryotic
microscopic algae, preferentially belonging to the classes or
superclasses Chlorophyceae, Chrysophyceae, Prymnesiophyceae,
Diatomae or Bacillariophyta, Euglenophyceae, Rhodophyceae, or
Trebouxiophyceae. Preferentially, the genetically modified
microalgae according to the invention are selected from
Nannochloropsis sp. (e.g. Nannochloropsis oculata, Nannochloropsis
gaditana, Nannochloropsis salina), Tetraselmis sp. (e.g.
Tetraselmis suecica, Tetraselmis chuii), Chlorella sp. (e.g.
Chlorella salina, Chlorella protothecoides, Chlorella ellipsoidea,
Chlorella emersonii, Chlorella minutissima, Chlorella pyrenoidosa,
Chlorella sorokiniana, Chlorella vulgaris), Chlamydomonas sp. (e.g.
Chlamydomonas reinhardtii) Dunaliella sp. (e.g. Dunaliella
tertiolecta, Dunaliella salina), Phaeodactulum tricornutum,
Botrycoccus braunii, Chroomonas salina, Cyclotella cryptica,
Cyclotella sp., Ettlia texensis, Euglena gracilis, Gymnodinium
nelsoni, Haematococcus pluvialis, Isochrysis galbana, Monoraphidium
minutum, Monoraphidium sp, Neochloris oleoabundans, Nitzschia
laevis, Onoraphidium sp., Pavlova lutheri, Phaeodactylum
tricornutum, Porphyridium cruentum, Scenedesmus sp. (e.g.
Scenedesmus obliquuus, Scenedesmus quadricaulaula, Scenedesmus
sp.), Stichococcus bacillaris, Spirulina platensis, Thalassiosira
sp.
[0036] In one embodiment, the genetically modified microorganism
according to the invention is a bacterium, preferentially selected
from phyla Acidobacteria, Actinobacteria, Aquificae,
Bacterioidetes, Chlamydia, Chlorobi, Chloroflexi, Chrysiogenetes,
Cyanobacteria, Deferribacteres, Deinococcus-Thermus, Dictyoglomi,
Fibrobacteres, Firmicutes, Fusobacteria, Gemmatimonadetes,
Nitrospirae, Planctomycetes, Proteobacteria, Spirochaetes,
Thermodesulfobacteria, Thermomicrobia, Thermotogae, or
Verrucomicrobia. Preferably, the genetically modified bacterium
according to the invention belongs to the genus Acaryochloris,
Acetobacter, Actinobacillus, Agrobacterium, Alicyclobacillus,
Anabaena, Anacystis, Anaerobiospirillum, Aquifex, Arthrobacter,
Arthrospira, Azobacter, Bacillus, Brevibacterium, Burkholderia,
Chlorobium, Chromatium, Chlorobaculum, Clostridium,
Corynebacterium, Cupriavidus, Cyanothece, Enterobacter,
Deinococcus, Erwinia, Escherichia, Geobacter, Gloeobacter,
Gluconobacter, Hydrogenobacter, Klebsiella, Lactobacillus,
Lactococcus, Mannheimia, Mesorhizobium, Methylobacterium,
Microbacterium, Microcystis, Nitrobacter, Nitrosomonas, Nitrospina,
Nitrospira, Nostoc, Phormidium, Prochlorococcus, Pseudomonas,
Ralstonia, Rhizobium, Rhodobacter, Rhodococcus, Rhodopseudomonas,
Rhodospirillum, Salmonella, Scenedesmun, Serratia, Shigella,
Staphylococcus, Streptomyces, Synechoccus, Synechocystis,
Thermosynechococcus, Trichodesmium, or Zymomonas. Also preferably,
the genetically modified bacterium according to the invention is
selected from the species Agrobacterium tumefaciens,
Anaerobiospirillum succiniciproducens, Actinobacillus succinogenes,
Aquifex aeolicus, Aquifex pyrophilus, Bacillus subtilis, Bacillus
amyloliquefacines, Brevibacterium ammoniagenes, Brevibacterium
immariophilum, Clostridium pasteurianum, Clostridium ljungdahlii,
Clostridium acetobutylicum, Clostridium beigerinckii,
Corynebacterium glutamicum, Cupriavidus necator, Cupriavidus
metallidurans, Enterobacter sakazakii, Escherichia coli,
Gluconobacter oxydans, Hydrogenobacter thermophilus, Klebsiella
oxytoca, Lactococcus lactis, Lactobacillus plantarum, Mannheimia
succiniciproducens, Mesorhizobium loti, Pseudomonas aeruginosa,
Pseudomonas mevalonii, Pseudomonas pudica, Pseudomonas putida,
Pseudomonas fluorescens, Rhizobium etli, Rhodobacter capsulatus,
Rhodobacter sphaeroides, Rhodospirillum rubrum, Salmonella
enterica, Salmonella enterica, Salmonella typhi, Salmonella
typhimurium, Shigella dysenteriae, Shigella flexneri, Shigella
sonnei, Staphylococcus aureus, Streptomyces coelicolor, Zymomonas
mobilis, Acaryochloris marina, Anabaena variabilis, Arthrospira
platensis, Arthrospira maxa, Chlorobium tepidum, Chlorobaculum sp.,
Cyanothece sp., Gloeobacter violaceus, Microcystis aeruginosa,
Nostoc punctiforme, Prochlorococcus marinus, Synechococcus
elongatus, Synechocystis sp., Thermosynechococcus elongatus,
Trichodesmium erythraeum, and Rhodopseudomonas palustris.
[0037] Expression of a Functional RuBisCO and a Functional PRK
[0038] According to the invention, the microorganism can naturally
express a functional RuBisCO and a functional PRK. This is the
case, for example, for photosynthetic microorganisms such as
microalgae and cyanobacteria.
[0039] There are several forms of RuBisCO in nature (Tabita et al.,
J Exp Bot. 2008; 59(7):1515-24. doi: 10.1093/jxb/erm361). Forms I,
II and III catalyze the carboxylation and oxygenation reactions of
ribulose-1,5-biphosphate. Form I is present in eukaryotes and
bacteria. It consists of two types of subunits: large subunits
(RbcL) and small subunits (RbcS). The functional enzyme complex is
a hexadecamer consisting of eight L subunits and eight S subunits.
The correct assembly of these subunits also requires the
intervention of at least one specific chaperone: RbcX (Liu et al.,
Nature. 2010 Jan. 14; 463(7278):197-202. doi: 10.1038/nature08651).
Form II is mainly found in proteobacteria, archaea (Archaea or
archaebacteria) and dinoflagellate algae. Its structure is much
simpler: it is a homodimer (formed by two identical RbcL subunits).
Depending on the organism, the genes encoding a type I RuBisCO may
be called rbcL/rbcS (for example Synechococcus elongatus), or
cbxLC/cbxSC, cfxLC/cfxSC, cbbL/cbbS (for example Cupriavidus
necator). Depending on the organism, the genes encoding a type II
RuBisCO are generally called cbbM (for example Rhodospirillum
rubrum). Form III is present in the archaea. It is generally found
in the form of dimers of the RbcL subunit, or in pentamers of
dimers. Depending on the organism, the genes encoding a type III
RuBisCO may be called rbcL (for example Thermococcus kodakarensis),
cbbL (for example Haloferax sp.).
[0040] Two classes of PRKs are known: class I enzymes found in
proteobacteria are octamers, while class II enzymes found in
cyanobacteria and plants are tetramers or dimers. Depending on the
organism, the genes encoding a PRK may be called prk (for example
Synechococcus elongatus), prkA (for example Chlamydomonas
reinhardtii), prkB (for example Escherichia coli), prk1, prk2 (for
example Leptolyngbya sp.), cbbP (for example Nitrobacter vulgaris)
or cfxP (for example Cupriavidus necator).
[0041] In the case where the microorganism used does not naturally
express a functional RuBisCO and a functional PRK, said
microorganism is genetically modified to express heterologous
RuBisCO and PRK. Advantageously, in such a case, the microorganism
is transformed so as to integrate into its genome one or more
expression cassettes integrating the sequences encoding said
proteins, and advantageously the appropriate transcription factors.
Depending on the type of RuBisCO to be expressed, it may also be
necessary to have one or more chaperone proteins expressed by the
microorganism, in order to promote the proper assembly of the
subunits forming the RuBisCO. This is particularly the case for
type I RuBisCO, where the introduction and expression of genes
encoding a specific chaperone (Rbcx) and generalist chaperones
(GroES and GroEL, for example) are necessary to obtain a functional
RuBisCO. Application WO2015/107496 describes in detail how to
genetically modify a yeast to express a functional type I RuBisCO
and PRK. It is also possible to refer to the method described in
GUADALUPE-MEDINA et al. (Biotechnology for Biofuels, 6, 125,
2013).
[0042] In one embodiment, the microorganism is genetically modified
to express a type I RuBisCO. In another embodiment, the
microorganism is genetically modified to express a type II RuBisCO.
In another embodiment, the microorganism is genetically modified to
express a type III RuBisCO.
[0043] Tables 1 and 2 below list, as examples, sequences encoding
RuBisCO and PRK that can be used to transform a microorganism to
express a functional RuBisCO and a functional PRK.
TABLE-US-00001 TABLE 1 Examples of sequences encoding a RuBisCO
Gene GenBank GI Organism rbcL BAD78320.1 56685098 Synechococcus
elongatus rbcS BAD78319.1 56685097 Synechococcus elongatus cbbL2
CAJ96184.1 113529837 Cupriavidus necator cbbS P09658.2 6093937
Cupriavidus necator cbbM YP_427487.1 132036 Rhodospirillum rubrum
cbbM Q21YM9.1 115502580 Rhodoferax ferrireducens cbbM Q479W5.1
115502578 Dechloromonas aromatica rbcL O93627.5 37087684
Thermococcus kodakarensis cbbL CQR50548.1 811260688 Haloferax sp.
Arc-Hr
TABLE-US-00002 TABLE 2 Examples of sequences encoding a PRK Gene
GenBank GI Organism prk BAD78757.1 56685535 Synechococcus elongatus
cfXP P19923.3 125575 Cupriavidus necator PRK P09559.1 125579
Spinacia oleracea cbbP P37100.1 585367 Nitrobacter vulgaris
[0044] Inhibition of Glycolysis
[0045] According to the invention, the glycolysis pathway is at
least partially inhibited, so that the microorganism is no longer
able to use this metabolic pathway normally (FIG. 1--glycolysis).
In other words, the microorganism no longer has the ability to
assimilate glucose in a similar way to a wild-type microorganism,
in which the glycolysis pathway has not been inhibited
(independently of any other genetic modification).
[0046] In one particular embodiment, the microorganism is
genetically modified to inhibit, totally or partially, glycolysis
downstream of the production of glyceraldehyde-3-phosphate
(G3P).
[0047] For example, glycolysis is inhibited upstream of the
production of 1,3-biphospho-D-glycerate (1,3-BPG) or upstream of
the production of 3-phosphoglycerate (3PG).
[0048] Depending on the microorganism, the reactions involved
between glyceraldehyde-3-phosphate (G3P) and 3-phosphoglycerate
(3PG) can be managed (i) by two enzymes acting concomitantly,
glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12, abbreviated
GAPDH or more rarely G3PDH) and phosphoglycerate kinase (E.C.
2.7.2.3, abbreviated PGK), or (ii) by a single non-phosphorylating
glyceraldehyde 3-phosphate dehydrogenase enzyme (EC 1.2.1.9,
abbreviated GAPN).
[0049] Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyzes
the reversible conversion of G3P to 1,3-biphospho-D-glycerate
(1,3-BPG), using the pair NAD.sup.+/NADH as electron donor/acceptor
in the direction of the reaction. Depending on the organism, the
genes encoding GAPDH may be called gapA, gapB, gapC (e.g.
Escherichia coli, Arabidopsis thaliana), GAPDH, GAPD, G3PD, GAPDHS
(e.g. Homo sapiens), TDH1, TDH2, TDH3 (e.g. Saccharomyces
cerevisiae), gap, gap2, gap3 (e.g. Mycobacterium sp., Nostoc
sp.).
[0050] Phosphoglycerate kinase (PGK) catalyzes the reversible
conversion of 1,3-BPG to 3PG, using the pair ATP/ADP as cofactor.
Depending on the organism, the genes encoding PGK may be called
PGK, PGK1, PGK1, PGK2, PGK3, pgkA, PGKB, PGKC, cbbK, cbbKC, cbbKP
(e.g. Cupriavidus necator).
[0051] Non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase
(GAPN) catalyzes the conversion of G3P to 3PG, without going
through 1,3-BPG. This reaction is catalyzed in the presence of the
cofactor pair NADP.sup.+/NADPH, which acts as an electron acceptor.
Depending on the organism, the genes encoding GAPN may be called
GAPN (e.g. Bacillus sp., Streptococcus sp.), GAPN1 (e.g.
Chlamydomonas sp.).
[0052] In one particular example, the microorganism is genetically
modified so that the expression of the gene encoding glyceraldehyde
3-phosphate dehydrogenase is at least partially inhibited.
Preferentially, gene expression is completely inhibited.
[0053] Alternatively or additionally, the expression of the gene
encoding phosphoglycerate kinase may also be at least partially
inhibited. Preferentially, gene expression is completely
inhibited.
[0054] Alternatively, the microorganism is genetically modified so
that the expression of the gene encoding non-phosphorylating
glyceraldehyde-3-phosphate dehydrogenase is at least partially
inhibited. Preferentially, gene expression is completely
inhibited.
[0055] Tables 3, 4 and 5 below list, as examples, the sequences
encoding a glyceraldehyde 3-phosphate dehydrogenase, a
phosphoglycerate kinase and a non-phosphorylating
glyceraldehyde-3-phosphate dehydrogenase that can be inhibited
depending on the target microorganism. The skilled person knows
which gene corresponds to the enzyme of interest to be inhibited
depending on the microorganism.
TABLE-US-00003 TABLE 3 Examples of sequences encoding a GAPDH Gene
GenBank GI Organism gapA NP_416293.1 947679 Escherichia coli TDH1
NP_012483.3 398364523 Saccharomyces cerevisiae TDH2 NP_012542.1
6322468 Saccharomyces cerevisiae TDH3 NP_011708.3 398366083
Saccharomyces cerevisiae gap ECC36949.1 378544675 Mycobacterium
tuberculosis gap2 P34917.2 92090599 Nostoc sp.
TABLE-US-00004 TABLE 4 Examples of sequences encoding a PGK Gene
GenBank GI Organism pgk AKL94701.1 831186507 Clostridium aceticum
PGK1 NP_009938.2 10383781 Saccharomyces cerevisiae pgk BAG04189.1
166089481 Microcystis aeruginosa PGKA AAG34561.2 22711882
Dictyostelium discoideum PGKB CAJ03534.1 68126221 Leishmania major
cbbKC AAC43444.1 976365 Cupriavidus necator pgk CAK45271.1 4982539
Aspergillus niger pgk EAU38870.1 4354973 Aspergillus terreus
TABLE-US-00005 TABLE 5 Examples of sequences encoding a GAPN Gene
GenBank GI Organism gapN CUB58597.1 924094571 Bacillus subtilis
GAPN NP_358622.1 933338 Streptococcus pneumoniae GAPN1 EDP03116.1
542583 Chlamydomonas reinhardtii
[0056] In general, the production of 3-phosphoglycerate (3PG) is no
longer possible through glycolysis, or at least significantly
reduced, in the genetically modified microorganism according to the
invention.
[0057] In a particular exemplary embodiment, the microorganism is a
yeast of the genus Saccharomyces cerevisiae in which the expression
of the TDH1 (Gene ID: 853395), TDH2 (Gene ID: 853465) and/or TDH3
gene (Gene ID: 853106) is at least partially inhibited.
[0058] In another particular exemplary embodiment, the
microorganism is a yeast of the genus Saccharomyces cerevisiae in
which the expression of the PGK1 gene (Gene ID: 5230) is at least
partially inhibited.
[0059] In another exemplary embodiment, the microorganism is a
yeast of the genus Saccharomyces cerevisiae in which the expression
of the PGK1 gene (Gene ID: 5230), the expression of the TDH1 gene
(Gene ID: 853395), TDH2 (Gene ID: 853465) and/or the expression of
the TDH3 gene (Gene ID: 853106) are at least partially
inhibited.
[0060] In a particular exemplary embodiment, the microorganism is
an Escherichia coli bacterium in which the expression of the gapA
gene (Gene ID: 947679) is at least partially inhibited.
[0061] In another particular exemplary embodiment, the
microorganism is an Escherichia coli bacterium in which the
expression of the pgk gene (Gene ID: 947414) is at least partially
inhibited.
[0062] In another exemplary embodiment, the microorganism is an E.
coli bacterium in which the expression of the pgk gene (Gene ID:
947414), and/or the expression of the gapA gene (Gene ID: 947679)
are at least partially inhibited.
[0063] According to the invention, the genetically modified
microorganism, which expresses a functional RuBisCO and a
functional PRK, is on the other hand capable of producing 3PG by
capturing CO.sub.2 from ribulose-5-phosphate produced by the
pentose phosphate pathway (FIG. 2).
[0064] Since the enzymes necessary for the metabolism of 3PG to
pyruvate are not inhibited in the microorganism, said microorganism
can then metabolize 3PG to produce pyruvate and ATP.
[0065] Thus, the genetically modified microorganism is able to
produce pyruvate and NADPH cofactors using CO.sub.2 as
complementary carbon source.
[0066] In the context of the invention, "complementary" carbon
source means that the microorganism uses CO.sub.2 as a partial
carbon source, in addition to the carbon atoms provided by
fermentable sugars (glucose, galactose, sucrose, fructose, etc.),
which constitute the majority or main carbon source for pyruvate
production.
[0067] Thus, the genetically modified microorganism according to
the invention makes it possible to increase carbon yield, by fixing
and using the CO.sub.2 normally lost during glucose metabolism via
the pentose phosphate pathway, for the production of pyruvate (and
subsequently molecules of interest).
[0068] Inhibition of the Oxidative Branch of the Pentose Phosphate
Pathway
[0069] In one particular embodiment, the genetically modified
microorganism according to the invention is also modified in such a
way that the oxidative branch of the pentose phosphate pathway is
also at least partially inhibited.
[0070] Preferentially, the microorganism is genetically modified to
inhibit the oxidative branch of the pentose phosphate pathway
upstream of ribulose-5-phosphate production (FIG. 1--pentose
phosphate pathway).
[0071] The interruption of the oxidative branch of the pentose
phosphate pathway upstream of ribulose-5-phosphate (Ru5P)
production specifically targets one or more reactions in the Ru5P
synthesis process from glucose-6-phosphate (G6P). This synthesis is
generally catalyzed by the successive actions of three enzymes: (i)
glucose-6-phosphate dehydrogenase (EC. 1.1.1.49, abbreviated
G6PDH), (ii) 6-phosphogluconolactonase (E.C. 3.1.1.31, abbreviated
PGL), and (iii) 6-phosphogluconate dehydrogenase (EC 1.1.1.44,
abbreviated PGD).
[0072] Glucose-6-phosphate dehydrogenase (G6PDH) catalyzes the
first reaction of the pentose phosphate pathway, i.e. the oxidation
of glucose-6-phosphate to 6-phosphogluconolactone (6PGL), with
concomitant reduction of one molecule of NADP to NADPH. Depending
on the organism, the genes encoding G6PDH may be called G6PD (for
example in Homo sapiens), G6pdx (for example in Musculus), gsdA
(for example in Aspergillus nidulans), zwf (for example in
Escherichia coli), or ZWF1 (for example in Saccharomyces
cerevisiae).
[0073] 6-Phosphogluconolactonase (PGL) is a hydrolase that
catalyzes the synthesis of 6-phosphogluconate (6PGA) from 6PGL.
Depending on the organism, the genes encoding PGL may be called pgl
(for example in Escherichia coli, Synechocystis sp.) pgls (for
example in Rhodobacteraceae bacterium), or SOL (for example in
Saccharomyces cerevisiae).
[0074] 6-Phosphogluconate dehydrogenase (PGD) is an oxidoreductase
that catalyzes the synthesis of Ru5P from 6PGA, with concomitant
reduction of an NADP molecule to NADPH and emission of a CO.sub.2
molecule. Depending on the organism, the genes encoding PGD may be
called gnd (for example in Escherichia coli, Saccharomyces
cerevisiae), PGD (for example in Homo sapiens), gntZ (for example
in Bacillus subtilis), or 6-PGDH (for example in Lactobacillus
paracollinoides).
[0075] In one particular example, the microorganism is genetically
modified so that the expression of the gene encoding
glucose-6-phosphate dehydrogenase is at least partially inhibited.
Preferentially, gene expression is completely inhibited.
[0076] Alternatively or additionally, the microorganism is
genetically modified so that the expression of the gene encoding
6-phosphogluconolactonase is at least partially inhibited.
Preferentially, gene expression is completely inhibited.
[0077] Alternatively or additionally, the microorganism is
genetically modified so that the expression of the gene encoding
6-phosphogluconate dehydrogenase is at least partially inhibited.
Preferentially, gene expression is completely inhibited.
[0078] Tables 6, 7 and 8 below list, as examples, the sequences
encoding a glucose-6-phosphate dehydrogenase, a
6-phosphogluconolactonase and a 6-phosphogluconate dehydrogenase
that can be inhibited depending on the target microorganism. The
skilled person knows which gene corresponds to the enzyme of
interest to be inhibited depending on the microorganism.
TABLE-US-00006 TABLE 6 Examples of sequences encoding a G6PDH Gene
GenBank GI Organism zwf BAA15660.1 946370 Escherichia coli ZWF1
NP_014158.1 6324088 Saccharomyces cerevisiae gsdA CAA54841.1
1523786 Aspergillus nidulans gsdA CAK37895.1 4979751 Aspergillus
niger gsdA EAU38380.1 4316232 Aspergillus terreus
TABLE-US-00007 TABLE 7 Examples of sequences encoding a PGL Gene
GenBank GI Organism pgl BAA35431.1 4062334 Escherichia coli pgl
BAK51770.1 339275283 Synechocystis pgls KPQ07176.1 938272062
Rhodobacteraceae bacterium SOL3 KZV10901.1 1023943655 Saccharomyces
cerevisiae
TABLE-US-00008 TABLE 8 Examples of sequences encoding a PGD Gene
GenBank GI Organism gnd ALI40222.1 937519736 Escherichia coli GND1
EDN62420.1 151944127 Saccharomyces cerevisiae gntZ NP_391888.1
16081060 Bacillus subtilis 6-PGDH WP_054711110.1 938929230
Lactobacillus paracollinoides
[0079] In general, the production of ribulose-5-phosphate (Ru5P) is
no longer possible through the pentose phosphate pathway, or at
least significantly reduced, in the genetically modified
microorganism according to the invention.
[0080] In a particular exemplary embodiment, the microorganism is a
yeast of the genus Saccharomyces cerevisiae in which the expression
of the ZWF1 gene is at least partially inhibited.
[0081] In one particular example, the yeast of the genus
Saccharomyces cerevisiae is genetically modified so that the
expression of the TDH1, TDH2, TDH3 and/or PGK1 genes, and the
expression of the ZWF1 gene are at least partially inhibited.
[0082] In another particular exemplary embodiment, the
microorganism is a bacterium of the genus Escherichia coli in which
the expression of the zwf gene is at least partially inhibited.
[0083] In one particular example, the bacterium of the genus
Escherichia coli is genetically modified so that the expression of
the gapA and/or pgk genes, and the expression of the zwf gene are
at least partially inhibited.
[0084] In another example, the microorganism is a filamentous
fungus of the genus Aspergillus, such as Aspergillus niger or
Aspergillus terreus, genetically modified so that the expression of
the pgk and gsdA genes is partially inhibited.
[0085] According to the invention, the genetically modified
microorganism, which expresses a functional RuBisCO and a
functional PRK, and whose glycolysis pathway and oxidative branch
of the pentose phosphate pathway are at least partially inhibited,
is no longer capable of producing 3PG via the glycolysis pathway or
Ru5P via the oxidative branch of the pentose phosphate pathway. On
the other hand, it is capable of producing Ru5P by diverting the
production of fructose-6-phosphate (F6P) and/or
glyceraldehyde-3-phosphate (G3P), produced at the beginning of
glycolysis (upstream of inhibition). This production is possible
thanks to the enzymes transketolase (EC 2.2.1.1), transaldolase (EC
2.2.1.2), ribose-5-phosphate isomerase (EC 5.3.1.6), and
ribulose-5-phosphate epimerase (EC 5.1.3.1) naturally present and
active in the microorganisms (FIG. 3).
[0086] Since the enzymes necessary for the metabolism of 3PG to
pyruvate are not inhibited in the microorganism according to the
invention, said microorganism can then metabolize 3PG to produce
pyruvate and ATP.
[0087] Thus, the genetically modified microorganism is able to
produce pyruvate by using exogenous CO.sub.2 as complementary
carbon source.
[0088] Thus, the genetically modified microorganism according to
the invention makes it possible to increase the carbon yield, by
fixing and using exogenous CO.sub.2, for the production of pyruvate
(and subsequently molecules of interest). Here again, there is an
increase in carbon yield.
[0089] Inhibition of the Entner-Doudoroff Pathway
[0090] In one particular embodiment, the genetically modified
microorganism according to the invention has an Entner-Doudoroff
pathway, and this is at least partially inhibited. This pathway,
mainly found in bacteria (especially Gram-negative bacteria), is an
alternative to glycolysis and the pentose pathway for the
production of pyruvate from glucose. More precisely, this pathway
connects to the pentose phosphate pathway at P-gluconate to feed
glycolysis, particularly at pyruvate.
[0091] Preferentially, the microorganism is genetically modified to
inhibit Entner-Doudoroff pathway reactions downstream of
6-phosphogluconate production. This inhibition eliminates a
possible competing pathway, and ensures the availability of
6-phosphogluconate as a substrate for PRK/RuBisCO engineering.
[0092] The interruption of the Entner-Doudoroff pathway downstream
of 6-phosphogluconate production specifically targets one or more
reactions in the pyruvate synthesis process from
6-phosphogluconate. This synthesis is initiated by the successive
actions of two enzymes: (i) 6-phosphogluconate dehydratase
("EDD"--EC. 4.2.1.12), and (ii) 2-dehydro-3-deoxy-phosphogluconate
aldolase ("EDA"--E.C. 4.1.2.14).
[0093] 6-Phosphogluconate dehydratase catalyzes the dehydration of
6-phosphogluconate to 2-keto-3-deoxy-6-phosphogluconate. Depending
on the organism, the genes encoding 6-phosphogluconate dehydratase
may be called edd (GenBank NP_416365, for example, in Escherichia
coli), or ilvD (for example, in Mycobacterium sp.).
[0094] 2-Dehydro-3-deoxy-phosphogluconate aldolase catalyzes the
synthesis of a pyruvate molecule and a glyceraldehyde-3-phosphate
molecule from the 2-keto-3-deoxy-6-phosphogluconate produced by
6-phosphogluconate dehydratase. Depending on the organism, the
genes encoding 2-dehydro-3-deoxy-phosphogluconate aldolase may be
called eda (GenBank NP_416364, for example, in Escherichia coli),
or kdgA (for example in Thermoproteus tenax), or dgaF (for example
in Salmonella typhimurium).
[0095] In one particular example, the microorganism is genetically
modified so that the expression of the gene encoding
6-phosphogluconate dehydratase is at least partially inhibited.
Preferentially, gene expression is completely inhibited.
[0096] Alternatively or additionally, the microorganism is
genetically modified so that the expression of the gene encoding
2-dehydro-3-deoxy-phosphogluconate aldolase is at least partially
inhibited. Preferentially, gene expression is completely
inhibited.
[0097] Tables 9 and 10 below list, as examples, the sequences
encoding a 6-phosphogluconate dehydratase and a
2-dehydro-3-deoxy-phosphogluconate aldolase that can be inhibited
depending on the target microorganism. The skilled person knows
which gene corresponds to the enzyme of interest to be inhibited
depending on the microorganism.
TABLE-US-00009 TABLE 9 Examples of sequences encoding an EDD Gene
GenBank GI Organism edd NP_416365.1 16129804 Escherichia coli ilvD
CND70554.1 893638835 Mycobacterium tuberculosis edd AJQ65426.1
764046652 Salmonella enterica
TABLE-US-00010 TABLE 10 Examples of sequences encoding an EDA Gene
GenBank GI Organism eda AKF72280.1 817591701 Escherichia coli kdgA
Q704D1.1 74500902 Thermoproteus tenax eda O68283.2 81637643
Pseudomonas aeruginosa
[0098] In general, in this embodiment, pyruvate production is no
longer possible via the Entner-Doudoroff pathway, or at least
significantly reduced.
[0099] In a particular exemplary embodiment, the microorganism is a
bacterium of the genus Escherichia coli in which the expression of
the edd gene is at least partially inhibited.
[0100] In one particular example, the bacterium of the genus
Escherichia coli is genetically modified so that the expression of
the gapA, and edd genes are at least partially inhibited.
[0101] According to the invention, the genetically modified
microorganism, which expresses a functional RuBisCO and a
functional PRK, and whose glycolysis pathway and Entner-Doudoroff
pathway are at least partially inhibited, is no longer capable of
producing 3PG by glycolysis or pyruvate by the Entner-Doudoroff
pathway. The carbon flow from glucose is therefore preferably
directed towards PRK/RuBisCO engineering.
[0102] Production of Molecules of Interest
[0103] According to the invention, the genetically modified
microorganism is transformed so as to produce an exogenous molecule
of interest and/or to overproduce an endogenous molecule of
interest.
[0104] In the context of the invention, molecule of interest
preferentially refers to a small organic molecule with a molecular
mass less than or equal to 0.8 kDa.
[0105] In general, genetic modifications made to the microorganism,
as described above, improve the carbon yield of the synthesis
and/or bioconversion pathways of molecules of interest.
[0106] In the context of the invention, "improved" yield refers to
the quantity of the finished product. In general, in the context of
the invention, the carbon yield corresponds to the ratio of
quantity of finished product to quantity of fermentable sugar,
particularly by weight. According to the invention, the carbon
yield is increased in the genetically modified microorganisms
according to the invention, compared with wild-type microorganisms,
placed under identical culture conditions. Advantageously, the
carbon yield is increased by 2%, 5%, 10%, 15%, 18%, 20%, or more.
The genetically modified microorganism according to the invention
may produce a larger quantity of molecules of interest (finished
product) than heterologous molecules produced by a genetically
modified microorganism simply to produce or overproduce that
molecule. According to the invention, the genetically microorganism
may also overproduce an endogenous molecule compared with the
wild-type microorganism. The overproduction of an endogenous
molecule is mainly understood in terms of quantities.
Advantageously, the genetically modified microorganism produces at
least 20%, 30%, 40%, 50%, or more by weight of the endogenous
molecule than the wild-type microorganism. Advantageously, the
microorganism according to the invention is genetically modified so
as to produce or overproduce at least one molecule among amino
acids, terpenoids, terpenes, vitamins and/or vitamin precursors,
sterols, flavonoids, organic acids, polyols, polyamines, aromatic
molecules obtained from stereospecific hydroxylation, via an
NADP-dependent cytochrome p450, etc.
[0107] In one particular example, the microorganism is genetically
modified to overproduce at least one amino acid, preferentially
selected from arginine, lysine, methionine, threonine, proline,
glutamate, homoserine, isoleucine, valine, and .gamma.-aminobutyric
acid.
[0108] In one particular example, the microorganism is genetically
modified to produce or overproduce molecules from the terpenoid
pathway, such as farnesene, and from the terpene pathway.
[0109] In one particular example, the microorganism is genetically
modified to produce or overproduce a vitamin or precursor,
preferentially selected from pantoate, pantothenate,
transneurosporene, phylloquinone and tocopherols.
[0110] In one particular example, the microorganism is genetically
modified to produce or overproduce a sterol, preferentially
selected from squalene, cholesterol, testosterone, progesterone and
cortisone.
[0111] In one particular example, the microorganism is genetically
modified to produce or overproduce a flavonoid, preferentially
selected from frambinone and vestinone.
[0112] In one particular example, the microorganism is genetically
modified to produce or overproduce an organic acid, preferentially
selected from coumaric acid, 3-hydroxypropionic acid, citric acid,
oxalic acid, succinic acid, and itaconic acid.
[0113] In one particular example, the microorganism is genetically
modified to produce or overproduce a polyol, preferentially
selected from sorbitol, xylitol and glycerol.
[0114] In one particular example, the microorganism is genetically
modified to produce or overproduce a polyamine, preferentially
spermidine.
[0115] In one particular example, the microorganism is genetically
modified to produce or overproduce an aromatic molecule from a
stereospecific hydroxylation, via an NADP-dependent cytochrome
p450, preferentially selected from phenylpropanoids, terpenes,
lipids, tannins, fragrances, hormones.
[0116] In the case where the molecule of interest is obtained by
bioconversion, the genetically modified microorganism is
advantageously cultured in a culture medium including the substrate
to be converted. In general, the production or overproduction of a
molecule of interest by a genetically modified microorganism
according to the invention is obtained by culturing said
microorganism in an appropriate culture medium known to the skilled
person.
[0117] The term "appropriate culture medium" generally refers to a
sterile culture medium providing essential or beneficial nutrients
for the maintenance and/or growth of said microorganism, such as
carbon sources; nitrogen sources such as ammonium sulfate; sources
of phosphors, for example, potassium phosphate monobasic; trace
elements, for example, salts of copper, iodide, iron, magnesium,
zinc or molybdate; vitamins and other growth factors such as amino
acids or other growth promoters. An antifoam agent can be added as
needed. According to the invention, this appropriate culture medium
may be chemically defined or complex. The culture medium may thus
be identical or similar in composition to a synthetic medium, as
defined by Verduyn et al. (Yeast. 1992. 8:501-17), adapted by
Visser et al. (Biotechnology and bioengineering. 2002. 79:674-81),
or commercially available such as yeast nitrogen base (YNB) medium
(MP Biomedicals or Sigma-Aldrich).
[0118] In particular, the culture medium may include a simple
carbon source, such as glucose, galactose, sucrose, molasses, or
the by-products of these sugars, optionally supplemented with
CO.sub.2 as carbon co-substrate. According to the present
invention, the simple carbon source must allow the normal growth of
the microorganism of interest. It is also possible, in some cases,
to use a complex carbon source, such as lignocellulosic biomass,
rice straw, or starch. The use of a complex carbon source usually
requires pretreatment before use.
[0119] In one particular embodiment, the culture medium contains at
least one carbon source among monosaccharides such as glucose,
xylose or arabinose, disaccharides such as sucrose, organic acids
such as acetate, butyrate, propionate or valerate to promote
different kinds of polyhydroxyalkanoate (PHA), treated or untreated
glycerol.
[0120] Depending on the molecules to be produced and/or
overproduced, it is possible to exploit the supply of nutritional
factors (N, O, P, S, K, Mg, Fe, Mn, Co, Cu, Ca, Sn; Koller et al.,
Microbiology Monographs, G.-Q. Chen, 14: 85-119, (2010)). This is
particularly the case to promote the synthesis and intracellular
accumulation of polyhydroalkanoate (PHA) including
polyhydroxybutyrate (PHB).
[0121] According to the invention, any culture method allowing the
production on an industrial scale of molecules of interest can be
considered. Advantageously, the culture is done in bioreactors,
especially in batch, fed-batch and/or continuous culture mode.
Preferentially, the culture associated with the production of the
molecule of interest is in fed-batch mode corresponding to a
controlled supply of one or more substrates, for example by adding
a concentrated glucose solution whose concentration can be between
200 g/L and 700 g/L. A controlled supply of vitamins during the
process can also be beneficial to productivity (Alfenore et al.,
Appl Microbiol Biotechnol. 2002. 60:67-72). It is also possible to
add an ammonium salt solution to limit the nitrogen supply.
[0122] Fermentation is generally carried out in bioreactors, with
possible steps of solid and/or liquid precultures in Erlenmeyer
flasks, with an appropriate culture medium containing at least a
simple carbon source and/or an exogenous CO.sub.2 supply, necessary
for the production of the molecule of interest.
[0123] In general, the culture conditions of the microorganisms
according to the invention are easily adaptable by the skilled
person, depending on the microorganism and/or the molecule to be
produced/overproduced. For example, the culture temperature is
between 20.degree. C. and 40.degree. C. for yeasts, preferably
between 28.degree. C. and 35.degree. C., and more particularly
around 30.degree. C., for S. cerevisiae. The culture temperature is
between 25.degree. C. and 35.degree. C., preferably 30.degree. C.,
for Cupriavidus necator.
[0124] The invention therefore also relates to the use a
genetically modified microorganism according to the invention, for
the production or overproduction of a molecule of interest,
preferentially selected from amino acids, peptides, proteins,
vitamins, sterols, flavonoids, terpenes, terpenoids, fatty acids,
polyols and organic acids.
[0125] The invention also relates to a biotechnological process for
producing at least one molecule of interest, characterized in that
it comprises a step of culturing a genetically modified
microorganism according to the invention, under conditions allowing
the synthesis or bioconversion, by said microorganism, of said
molecule of interest, and optionally a step of recovering and/or
purifying said molecule of interest.
[0126] In one particular embodiment, the microorganism is
genetically modified to express at least one enzyme involved in the
synthesis of said molecule of interest.
[0127] In another particular embodiment, the microorganism is
genetically modified to express at least one enzyme involved in the
bioconversion of said molecule of interest.
[0128] The invention also relates to a process for producing a
molecule of interest comprising (i) inserting at least one sequence
encoding an enzyme involved in the synthesis or bioconversion of
said molecule of interest into a recombinant microorganism
according to the invention, (ii) culturing said microorganism under
conditions allowing the expression of said enzyme and optionally
(iii) recovering and/or purifying said molecule of interest.
[0129] For example, it is possible to overproduce citrate by a
fungus, particularly a filamentous fungus, such as Aspergillus
niger, genetically modified to express a functional PRK and a
functional type I or II RuBisCO, and in which the expression of the
pgk (Gene ID: 4982539) and gsdA (Gene ID: 497979751) genes is at
least partially inhibited.
[0130] It is also possible to overproduce itaconic acid by a
fungus, particularly a filamentous fungus, such as Aspergillus
terreus or Aspergillus niger, genetically modified to express a
functional PRK and a functional type I or II RuBisCO, and in which
the expression of the pgk (Gene ID: 4354973) and gsdA (Gene ID:
4316232) genes is at least partially inhibited.
[0131] Similarly, it is possible to produce farnesene by a yeast
such as a yeast of the genus Saccharomyces cerevisiae genetically
modified to express a functional PRK and a functional type I or II
RuBisCO, a farnesene synthase and in which the expression of a PGK1
gene (Gene ID: 5230) is at least partially inhibited.
[0132] It is also possible to overproduce glutamate by a bacterium,
such as a bacterium of the genus Escherichia coli, genetically
modified to express a functional PRK and a functional type I or II
RuBisCO, and in which the expression of the gapA gene (Gene ID:
947679) is at least partially inhibited. This overproduction can
also occur in a strain where at least partial inhibition of the
gapA gene is combined with at least partial inhibition of the zwf
gene (Gene ID: 946370).
[0133] Similarly, it is also possible to overproduce
.gamma.-aminobutyric acid by a bacterium, such as a bacterium of
the genus Escherichia coli, genetically modified to express a
functional PRK and a functional type I or II RuBisCO, as well as a
glutamate decarboxylase gadB (Gene ID: 946058), and in which the
expression of the gapA gene (Gene ID: 947679) is at least partially
inhibited. This overproduction can also occur in a strain where at
least partial inhibition of the gapA gene is combined with at least
partial inhibition of the zwf gene (Gene ID: 946370).
[0134] Similarly, it is possible to overproduce succinic acid and
oxalic acid by a bacterium, such as a bacterium of the genus
Escherichia coli, genetically modified to express a functional PRK
and a functional type I or II RuBisCO, as well as an enzymatic
activity allowing the oxidation of glyoxylate to oxalate,
preferentially a glyoxylate dehydrogenase FPGLOXDH1 (mRNA:
BAH29964.1), a glyoxylate oxidase GLO (mRNA: AOW73106.1), or a
lactate dehydrogenase LDHA (Gene ID: 3939), and in which the
expression of the gapA (Gene ID: 947679) and zwf (Gene ID: 946370)
genes is at least partially inhibited.
EXAMPLES
Example 1: Bioinformatics Analysis
[0135] a) Calculation of Theoretical Yields
[0136] i) Comparison of Carbon Fixation Yields from Glucose Between
a Wild-Type Strain Using the Pentose Phosphate Pathway and
Glycolysis and a Modified Strain According to the Invention
[0137] In order to evaluate the benefit of the modifications
described according to the invention, theoretical yield
calculations were carried out on the basis of the stoichiometry of
the reactions involved.
[0138] Two scenarios were analyzed: the improvement provided by
PRK-RuBisCO engineering (i) in a strain inhibited for glycolysis on
the yield of a NADPH-dependent biosynthetic pathway (for example
farnesene synthesis), and (ii) in a strain inhibited for glycolysis
and for the oxidative branch of the pentose phosphate pathway on
the yield of a biosynthetic pathway of interest (for example
citrate synthesis).
[0139] In the context of the improvement of NADPH-dependent
biosynthetic pathways, the theoretical balance of the formation of
NADPH and glyceraldehyde-3-phosphate (G3-P) from glucose via the
pentose phosphate pathway was calculated according to the following
equation (1):
3Glucose+5ATP+6NADP.sup.++3H.sub.2O.fwdarw.5G3-P+5ADP+6NADPH+11H.sup.++3-
CO.sub.2 (1)
[0140] Going down to pyruvate formation from G3P, we arrive at the
following balance:
3Glucose+5ADP+6NADP.sup.++5NAD.sup.++5P.sub.i.fwdarw.5Pyruvate+5ATP+6NAD-
PH+5NADH+11H.sup.++3CO.sub.2+2H.sub.2O (2)
[0141] If we normalize the balance for one mole of glucose, we
obtain the following yield:
Glucose+1.67ADP+2NADP.sup.++1.67NAD.sup.++1.67P.sub.i.fwdarw.1.67Pyruvat-
e+1.67ATP+2NADPH+1.67NADH+3.67H.sup.++CO.sub.2+0.67H.sub.2O (3)
[0142] Thus, by using the pentose phosphate pathway, 1.67 moles of
pyruvate and 2 moles of NADPH are produced from one mole of
glucose. However, one mole of carbon is lost by decarboxylation
when ribulose-5-phosphate is formed by 6-phosphogluconate
dehydrogenase (EC 1.1.1.44). In comparison, pyruvate formation by
the glycolysis pathway gives the following yield:
Glucose+2ADP+2NAD.sup.++2P.sub.i.fwdarw.2Pyruvate+2ATP+2NADH+2H.sup.++2H-
.sub.2O (4)
[0143] The maximum theoretical yield of pyruvate production by the
pentose phosphate pathway is therefore 0.82
g.sub.pyruvate/g.sub.glucose (g of synthesized pyruvate, per g of
glucose consumed), while it is 0.98 g.sub.pyruvate/g.sub.glucose by
the glycolysis pathway.
[0144] By integrating PRK/RuBisCO engineering into a strain
inhibited for glycolysis (for example .DELTA.PGK1 in S. cerevisiae
yeast), the carbon fixation flux is redirected to the oxidative
branch of the pentose phosphate pathway and then to PRK/RuBisCO
engineering (see FIG. 2). This flux is related to the end of the
glycolysis pathway, at the level of 3-phosphoglycerate (3PG)
formation, with the following yield:
Glucose+2ATP+2NADP.sup.++2H.sub.2O.fwdarw.2
3PG+2ADP+2NADPH+6H.sup.+ (5)
[0145] Going down to pyruvate formation from 3PG, we arrive at the
following balance:
Glucose+2NADP.sup.+.fwdarw.2Pyruvate+2NADPH+4H.sup.+ (6)
[0146] The integration of the modifications according to the
invention into a microorganism makes it possible to recover the
carbon molecule otherwise lost by decarboxylation in the pentose
pathway. The maximum theoretical carbon fixation yield is therefore
0.98 g.sub.pyruvate/g.sub.glucose, which improves by 20.5% the
yield obtained by the production of pyruvate by the pentose
phosphate pathway, while producing NADPH.
[0147] In a second case (see FIG. 3), PRK/RuBisCO engineering is
integrated into a strain that is both inhibited for glycolysis (for
example .DELTA.PGK1 in the case of S. cerevisiae yeast) and for the
oxidative branch of the pentose phosphate pathway (for example
.DELTA.ZWF1 in the case of S. cerevisiae yeast). The theoretical
balance of the formation of NADPH and 3-phosphoglycerate (3PG) from
glucose then becomes
2.5Glucose+6ATP+3CO.sub.2+3H.sub.2O.fwdarw.6 3PG+6ADP+12H.sup.+
(7)
[0148] Going down to pyruvate formation from 3PG, we arrive at the
following balance
2.5Glucose+3CO.sub.2.fwdarw.6Pyruvate++3H.sub.2O+6H.sup.+ (8)
[0149] If we normalize the balance for one mole of glucose, we
obtain the following yield:
Glucose+1.2CO.sub.2.fwdarw.2.4Pyruvate+1.2H.sub.2O+2.4H.sup.+
(9)
[0150] The integration of the modifications according to the
invention makes it possible to fix 1.2 additional carbon molecule
per mole of glucose consumed. The corresponding maximum theoretical
yield is 1.17 g.sub.pyruvate/g.sub.glucose, which is .about.20%
improvement compared with the carbon fixation yield of
glycolysis.
[0151] ii) Application to Citrate Production
[0152] In a second case, the calculation is applied to citrate
production in S. cerevisiae yeast, in a wild-type strain and in a
modified strain modified according to the invention incorporating
PRK/RuBisCO engineering and deleted for the PGK1 gene so as to
inhibit the glycolysis pathway, and for the ZWF1 gene to inhibit
the oxidative branch of the pentose pathway.
[0153] The production of citrate from pyruvate is summarized by the
following balance equation:
2Pyruvate+ATP+NAD.sup.++2H.sub.2O.fwdarw.Citrate+ADP+NADH+P.sub.i+3H.sup-
.+ (11)
[0154] This synthesis does not require NADPH, but 2 moles of
pyruvate. Optimally, a wild-type strain obtains these 2 moles of
pyruvate by glycolysis, from one mole of glucose according to
equation (4), with the following balance:
Glucose+ADP+3NAD.sup.++P.sub.i.fwdarw.Citrate+ATP+3NADH+5H.sup.+
(12)
[0155] The corresponding g.sub.citrate/g.sub.glucose yield is
1.07
[0156] In the context of a modified strain according to the
invention, inhibited for the glycolysis pathway and the pentose
phosphate pathway, the 2 pyruvates required are obtained with only
0.83 mole of glucose (see equation 9), with the following
balance:
0.83Glucose+CO.sub.2+ATP+NAD.sup.++H.sub.2O.fwdarw.Citrate+ADP+NADH+P.su-
b.i+5H.sup.+ (13)
[0157] The corresponding g.sub.citrate/g.sub.glucose yield is 1.28,
a maximum theoretical increase of about 20% compared with the yield
of the wild-type strain.
[0158] b) Simulation of Biosynthesis Yields by Flux Balance
Analysis
[0159] In a bioinformatics approach, flux balance analyses (FBAs)
were also performed to simulate the impact of the modifications
described according to the invention on the yield of different
biosynthetic pathways.
[0160] FBAs are based on mathematical models that simulate
metabolic networks at the genome scale (Orth et al., Nat
Biotechnol. 2010; 28: 245-248). Reconstructed networks contain the
known metabolic reactions of a given organism and integrate the
needs of the cell, in particular to ensure cell maintenance or
growth. FBAs make it possible to calculate the flow of metabolites
through these networks, making it possible to predict theoretical
growth rates as well as metabolite production yields.
[0161] i) Procedure
[0162] FBA simulations were performed with the OptFlux software
(Rocha et al., BMC Syst Biol. 2010 Apr. 19; 4:45. doi:
10.1186/1752-0509-4-45), and the Saccharomyces cerevisiae metabolic
model iMM904 (Mo et al., BMC Syst Biol. 2009 Mar. 25; 3:37. doi:
10.1186/1752-0509-37). This model has been modified to include the
improvements described according to the invention, including a
heterologous CO.sub.2 fixation pathway with (i) the addition of a
PRK-type reaction, (ii) the addition of a RuBisCO-type
reaction.
[0163] In particular exemplary embodiments, the reactions necessary
to simulate the production of molecules through heterologous
pathways have also been added to the model.
[0164] In a particular exemplary embodiment, a farnesene synthase
reaction (EC 4.2.3.46 or EC 4.2.3.47) has been added for the
heterologous production of farnesene.
[0165] In a second particular exemplary embodiment, acetoacetyl-CoA
reductase (EC 1.1.1.36) and poly-hydroxybutyrate synthase (EC
2.3.1.B2 or 2.3.1.B5) reactions were added to the model to simulate
a heterologous production pathway of .beta.-hydroxybutyrate, the
monomer of polyhydroxybutyrate.
[0166] In another particular exemplary embodiment, a glutamate
decarboxylase reaction (EC 4.1.1.15) was added for the heterologous
production of .gamma.-aminobutyric acid.
[0167] In another particular exemplary embodiment, an aconitate
decarboxylase reaction (EC 4.1.1.6) was added for the heterologous
production of itaconic acid.
[0168] In another particular exemplary embodiment, a lactate
dehydrogenase reaction (EC 1.1.1.27) was added for the heterologous
production of oxalate
[0169] The simulations were carried out by applying to the model a
set of constraints reproducible by the skilled person, aimed at
simulating the in vivo culture conditions of a strain of S.
cerevisiae under the conditions described according to the
invention (for example presence of unrestricted glucose in the
medium, aerobic culture condition).
[0170] In particular exemplary embodiments, simulations are
performed by virtually inactivating the reactions of the enzymes
PGK1 (for example glutamate, .beta.-hydroxybutyric acid, farnesene)
and ZWF1 (for example citrate production), in order to simulate the
decreases in glycolysis activity and the pentose phosphate pathway,
described according to the invention.
[0171] Simulations are carried out in parallel on an unmodified
"wild-type strain" model in order to evaluate the impact of the
improvements described according to the invention on the production
yield of the biosynthetic pathways tested.
[0172] ii) Results
[0173] The theoretical yields obtained and the percentages of
improvement provided by the invention are described in Table 11
below.
TABLE-US-00011 TABLE 11 Maximum theoretical production yields
evaluated by FBA on a wild-type strain and a modified strain
according to the modifications of the patent, for the production of
different molecules. Percentage improvement in theoretical Maximum
theoretical Maximum theoretical production mass production yields
yields with a modified strain efficiency with a wild-type strain
according to the invention g.sub.x/g.sub.GLUC Target Simulation
Mol.sub.x/ CMol.sub.x/ Mol.sub.x/ CMol.sub.x/ provided by molecule
conditions Mol.sub.GLUC CMol.sub.GLUC g.sub.x/g.sub.GLUC
Mol.sub.GLUC CMol.sub.GLUC g.sub.x/g.sub.GLUC the invention Citrate
.DELTA.PGK1, 1 1 1.07 1.2 1.2 1.28 +20% .DELTA.ZWF1, Itaconate
.DELTA.PGK1, 1 0.83 0.72 1.2 1 0.87 +20% .DELTA.ZWF1, Glutamate
.DELTA.PGK1 0.92 0.77 0.75 1.09 0.91 0.89 +18.7% .DELTA.PGK1, 1
0.83 0.82 1.2 1 0.98 +20% .DELTA.ZWF1, GABA .DELTA.PGK1, 1 0.67
0.57 1.2 0.8 0.69 +20% .DELTA.ZWF1, .beta.- .DELTA.PGK1 0.92 0.61
0.53 1.09 0.73 0.63 +18.2% Hydroxybutyric acid Farnesene
.DELTA.PGK1 0.21 0.54 0.24 0.24 0.59 0.27 +12.5% Co-production
Succinate .DELTA.PGK1, 1 0.67 0.66 1.2 0.8 0.79 +20% Oxalate
.DELTA.ZWF1, 1 0.33 0.5 1.2 0.4 0.6 +20% Mol.sub.x//Mol.sub.GLUC:
moles of molecule X produced, in relation to the moles of glucose
consumed CMol.sub.x/CMol.sub.GLUC:: moles of carbon of molecule X
produced, in relation to the moles of carbon of glucose consumed
g.sub.x/g.sub.GLUC: g of molecule X produced, in relation to the g
of glucose consumed.
Example 2: Improvement of Farnesene Production in S. cerevisiae
[0174] A Saccharomyces cerevisiae yeast strain, CEN.PK 1605 (Mat a
HIS3 leu2-3.112 trp1-289 ura3-52 MAL.28c) derived from the
commercial strain CEN.PK 113-7D (GenBank: JRIV00000000 is
engineered to produce NADPH without CO.sub.2 loss and thus allow
the improvement of alpha-farnesene production from glucose.
[0175] a) Inactivation of the Glycolysis Pathway
[0176] To that end, the glycolysis pathway was inactivated by
deletion of the PGK1 gene. Once glycolysis is inhibited, the
resulting yeast strain is no longer able to use glucose as a source
of carbon and energy. It is therefore necessary to supply the
biomass synthesis pathways with glycerol and the energy pathways
with ethanol. The strains in which PGK1 is deleted are grown on
YPGE (yeast extract peptone glycerol ethanol) medium.
[0177] The deletion of the PGK1 gene was obtained as follows:
[0178] The coding phase of the G418 resistance gene, derived from
the KanMX cassette contained on plasmid pUG6 (P30114--Euroscarf),
was amplified with the oligonucleotides CB101 (SEQ ID NO: 1) and
CB102 (SEQ ID NO: 2):
TABLE-US-00012 SEQ ID NO: 1: CB101 (forward):
5'-ACAGATCATCAAGGAAGTAATTATCTACTTTTTACAACAAAT
ATAAAACAATGGGTAAGGAAAAGACTCACGTTTC-3' SEQ ID NO: 2: CB102
(reverse): 5'-GGGAAAGAGAAAAGAAAAAAATTGATCTATCGATTTCAATTC
AATTCAATTTAGAAAAACTCATCGAGCATCAAATGAAAC-3'
[0179] The underlined portion of the oligonucleotides is perfectly
homologous to the Kan sequence and the rest of the sequence
corresponds to the regions adjacent to the coding phase of the PGK1
gene on the Saccharomyces cerevisiae genome so as to generate a PCR
amplicon containing at its ends homologous recombination sequences
of the PGK1 gene locus.
[0180] For the transformation reaction according to the skilled man
(Methods in Yeast Genetics, Cold Spring Harbor lab course manual,
1997; Gietz and Schiest, 1995, Methods in Molecular and Cellular
Biology 5[5]:225-269), strain CEN.PK 1605 was grown in a volume of
50 mL of complex rich medium YPD (yeast extract peptone dextrose)
at 30.degree. C. to an optical density at 600 nm of 0.8. The cells
were centrifuged for 5 minutes at 2,500 rpm at room
temperature.
[0181] The supernatant was removed and the cells were resuspended
in 25 mL of sterile water and centrifuged again for 5 minutes at
2,500 rpm at room temperature. After removing the supernatant, the
cells were resuspended in 400 .mu.L of 100 mM sterile lithium
acetate.
[0182] At the same time, a transformation mix was prepared in a 2
mL tube as follows: 250 .mu.L of 50% PEG, 10 .mu.L of "carrier" DNA
at 5 mg/mL, 36 .mu.L of 1 M lithium acetate, 5 or 10 .mu.L of
purified PCR reaction (deletion cassette) and 350 .mu.L of
water.
[0183] The resuspended cells (50 .mu.L) were added to the
transformation mixture and incubated at 42.degree. C. for 40
minutes in a water bath.
[0184] After incubation, the tube was centrifuged for 1 minute at
5,000 rpm at room temperature and the supernatant was discarded.
The cells were resuspended in 2 mL of YPGE (yeast extract peptone
glycerol ethanol) medium, transferred to a 14 mL tube and incubated
for 2 hours at 30.degree. C. at 200 rpm. The cells were then
centrifuged for 1 minute at 5,000 rpm at room temperature. The
supernatant was removed and the cells were resuspended in 1 mL of
sterile water and centrifuged again for 1 minute and resuspended in
100 .mu.L of sterile water and spread over 180 .mu.g/mL
YPGE+G418.
[0185] The colonies obtained were genotyped for the validation of
the deletion of the PGK1 gene and referenced EQ-0134 (CEN.PK1605
.DELTA.pgk1::kan).
[0186] b) Introduction of PRK--RuBisCO--Alpha-Farnesene Synthase
Enzymes
[0187] In order to reconstitute an alternative pathway to
glycolysis and allow the .DELTA.pgk1 strain to grow on glucose,
said strain has been modified to allow combinatorial expression of:
[0188] a gene encoding a phosphoribulokinase PRK which is grafted
onto the pentose phosphate pathway by consuming ribulose-5P to give
ribulose-1.5bisP and [0189] a type I RuBisCO (with the structural
genes RbcL and RbcS and the chaperones RbcX, GroES and GroEL).
RuBisCO consumes ribulose-1.5bisP and one mole of CO.sub.2 to form
3-phosphoglycerate downstream of the PGK1 deletion in the
glycolysis pathway.
[0190] This alternative pathway once again allows the strain to
consume glucose as its main source of carbon and energy.
[0191] To produce alpha-farnesene, the yeast lacks the
alpha-farnesene synthase gene (AFS1; SEQ ID NO: 71; GenBank
accession number AY182241).
[0192] Also, the seven genes required for PRK-RuBisCO engineering
(Table 12) were cloned on four plasmid vectors capable of
autonomous replication, with compatible origins of replication and
each carrying a different gene for complementation of auxotrophy or
of antibiotic resistance, allowing the selection of strains
containing the three or four plasmid constructs.
[0193] Two of these plasmids are single-copy, with an Ars/CEN
origin of replication and the third is multicopy with a 2.mu.
origin.
TABLE-US-00013 TABLE 12 Description of expression cassettes and
plasmid composition Codon Auxo- optimi- Termi- trophic GenBank
zation Promoter nator ori marker Plasmids RbcL BAD78320.1 Yes TDH3p
ADH1t 2.mu. URA3 pFPP45 RbcS BAD78319.1 Yes TEF1p PGK1t 2.mu. URA3
pFPP45 RbcX BAD80711.1 Yes TEF1p PGK1t ARS-CEN6 LEU2 pFPP56 GroES
U00096 No PGI1p CYC1t ARS-CEN6 LEU2 pFPP56 GroEL AP009048 No TDH3p
ADH1t ARS-CEN6 LEU2 pFPP56 PRK BAD78757.1 Yes Tet-OFF CYC1t
ARS416-CEN4 TRP1 pFPP20 alpha- AY182241 Yes TEF1p PGK1t 2.mu. NatMX
pL4 farnesene synthase (AFS1) Empty Tet-OFF CYC1t ARS416-CEN4 TRP1
pCM185 Empty ARS-CEN6 LEU2 pFL36 Empty TEF1p PGK1t 2.mu. URA3
pV51TEF
[0194] Genes from Synechococcus elongatus such as rbcL, rbcS, rbcX
and prk (as described in WO 2015107496 A1) and Malus domestica
alpha-farnesene synthase (Tippmann et al., Biotechnol Bioeng. 2016
January; 113(1):72-81) have been optimized for the use of codons in
Saccharomyces cerevisiae yeast.
[0195] According to the protocol previously described for yeast
transformation, strain EQ-0134 was grown in a volume of 50 mL of
complex rich medium YPGE (yeast extract peptone glycerol ethanol)
at 30.degree. C. The cells are centrifuged for 5 minutes at 2,500
rpm at room temperature. The supernatant is removed and the cells
are resuspended in 25 mL of sterile water and centrifuged again for
5 minutes at 2,500 rpm at room temperature. After removing the
supernatant, the cells are resuspended in 400 .mu.L of 100 mM
sterile lithium acetate. At the same time, the following
transformation mix is prepared: 250 .mu.L of 50% PEG, 10 .mu.L of
"carrier" DNA at 5 mg/mL, 36 .mu.L of 1 M lithium acetate, 10 .mu.L
(3 .mu.g of one of the following combinations, pFPP45+pFPP56+pFPP20
or pL4+pFPP45+pFPP56+pFPP20) and 350 .mu.L of water.
[0196] The resuspended cells (50 .mu.L) were added to the
transformation mixture and incubated at 42.degree. C. for 40
minutes in a water bath. After incubation, the tube was centrifuged
for 1 minute at 5,000 rpm at room temperature and the supernatant
was discarded. The cells were resuspended in 2 mL YNB (yeast
nitrogen base including ammonium sulfate) with glycerol and
ethanol, transferred to a 14 mL tube and incubated for 2 hours at
30.degree. C. under atmosphere enriched with 10% CO.sub.2. The
final mix is spread on YNB agar medium including ammonium
sulfate+CSM without LUW (leucine uracil, tryptophan)+nourseothricin
if applicable, with glycerol and ethanol as carbon sources.
[0197] According to the previously described protocol, strain
CEN.PK 1605 is transformed with the following plasmid combination:
pL4+pFL36+pCM185+pV51TEF.
[0198] The clones obtained were genotyped for all engineering genes
and then adapted on liquid medium YNB ammonium sulfate and glucose.
[0199] EQ-0153 (CEN.PK1605 .DELTA.pgk1::kan) (pFPP45+pFPP56+pFPP20)
[0200] EQ-0253 (CEN.PK1605 .DELTA.pgk1::kan)
(pL4+pFPP56+pFPP20+pFPP45) [0201] EQ-0353 (CEN.PK1605)
(pL4+pFL36+pCM185+pV51TEF)
[0202] c) Adaptation of Strains EQ-0153 and EQ-0253 to Growth in
Liquid Medium with Glucose and CO.sub.2.
[0203] Batch-mode cultures in Erlenmeyer flasks are carried out
with the appropriate culture medium and a 10% exogenous CO.sub.2
supply, in a shaking incubator (120 rpm, 30.degree. C.), with
inoculation at 0.05 OD 600 nm measured using an EON
spectrophotometer (BioTek Instruments). The strain of interest is
grown on YNB+CSM-LUW medium with 10 g/L glycerol and 7.5 g/L
ethanol, under conditions where PRK expression is not induced, and
in the presence of nourseothricin if appropriate. Under these
conditions, it is necessary to feed the strain before and after the
deletion of the PGK1 gene.
[0204] After obtaining a sufficient quantity of biomass, cultures
with a volume greater than or equal to 50 mL in Erlenmeyer flasks
of at least 250 mL are inoculated in order to adapt the strain to
the use of the PRK/RuBisCO engineering. This adaptation is carried
out on YNB+CSM-LUW culture medium with 20 g/L glucose, in the
presence of nourseothricin if necessary and an exogenous CO.sub.2
supply as described above.
[0205] After observation of a significant growth start, the strains
are adapted to a minimum mineral medium free of the amino acids and
nitrogenous bases included in the CSM-LUW, i.e. only YNB with 20
g/L glucose, nourseothricin if necessary and an exogenous CO.sub.2
supply as described above.
[0206] d) Production of Farnesene in Erlenmeyer Flasks
[0207] Saccharomyces cerevisiae strain EQ-0253, with a deletion in
the glycolytic pathway at the PGK1 gene, is grown to produce
farnesene while overproducing NADPH without CO.sub.2 loss, using a
PRK and a RuBisCO.
[0208] This strain of interest is compared with a reference strain
EQ-0353 producing farnesene following the introduction of a
heterologous alpha-farnesene synthase, without deletion of PGK1 or
addition of PRK and RuBisCO.
[0209] Strains EQ-0253 (CEN.PK1605 .DELTA.pgk1::kan)
(pL4+pFPP56+pFPP20+pFPP45) and EQ-0353 (CEN.PK1605)
(pL4+pFL36+pCM185+pV51TEF) were grown in a YNB medium with 20 g/L
D-glucose, to which 100 .mu.g/L nourseothricin was added. A
pre-culture containing 20 mL of culture medium was inoculated at
0.05 OD.sub.600 nm into a 250 mL baffled Erlenmeyer flask, shaken
at 120 rpm for 24 h at 30.degree. C. in a Minitron incubator with
an atmosphere regulated at 10% CO.sub.2. From the first
pre-culture, 50 mL of medium was inoculated at 0.05 OD.sub.600 nm
into a 250 mL Erlenmeyer and shaken at 120 rpm for 24 h at
30.degree. C., 10% CO.sub.2. The culture, also conducted in
Erlenmeyer flasks (500 mL, baffled) from the second pre-culture,
was inoculated at 0.05 OD.sub.600 nm into 100 mL of the same
culture medium, to which 50 .mu.g/mL ampicillin, 10 .mu.L antifoam
(Antifoam 204, Sigma, A6426) and 10% (v/v) dodecane were added
(Tippman et al., Talanta (2016), 146: 100-106). The cultures were
shaken at 120 rpm at 30.degree. C. in the presence of 10% CO.sub.2.
Growth was monitored by measuring turbidity at 600 nm.
[0210] To extract farnesene, 500 .mu.L of organic phase was
collected and centrifuged at 5,000 g for 5 min for complete
separation of the two phases. The organic phase was stored at
4.degree. C. until GC-MS analysis. The detection and quantification
of .alpha.-farnesene was performed by single quadrupole mass
spectrometry. A Zebron ZB-FFAP column was used with hydrogen as the
carrier gas at a fixed rate of 2.95 mL/min. The inlet temperature
was 260.degree. C., 1 .mu.L of sample was injected in splitless
mode. The initial oven temperature was 70.degree. C. (4 min) then
it was gradually increased to 160.degree. C. (7.degree. C./min)
then to 240.degree. C. (40.degree. C./min) where it was maintained
for 1.05 min. For mass spectrometric detection, the transfer line
and source temperatures were 250.degree. C. and 200.degree. C.
respectively. The mass acquisition was made between t=10 min and
t=20 min. An external calibration including seven points was
performed using the farnesene isomer mix (Sigma, W383902) for the
quantification of .alpha.-farnesene produced by the strains.
[0211] To quantify the glucose consumed by the strains, 500 .mu.L
of culture medium was collected at the same farnesene extraction
OD, centrifuged at 5,000 g, 5 min at 4.degree. C. The supernatant
was filtered (Minicart RC4, Sartorius 0.45 .mu.m) and stored in a
flask at -20.degree. C. The glucose contained in this sample was
quantified by UltiMate 3000 HPLC-UV (Thermo Scientific) equipped
with a pump, an 8.degree. C. refrigerated autosampler and a
refractive index (RI) detector (Precision Instruments IOTA 2). A
Rezex ROA-Organic Acid H.sup.+ column (8%) 150.times.7 8 mm, 8
.mu.m particle size (Phenomenex, 00H-0138-KO) was used with a
Carbo-H pre-column 4.times.3.0 mm. The temperature of the column
was 35.degree. C. and the flow rate was set at 0.5 mL/min.
Isocratic elution was performed with an aqueous mobile phase at 5
mM H.sub.2SO.sub.4 and lasted 30 min A volume of 20 .mu.L was
injected for each sample. The identification of compounds was based
on the comparison of retention times with standards. The external
calibration includes 10 points of variable glucose concentration
(0-20 g/L).
[0212] The carbon yield Y.sub..alpha.-farnesene/Glc is calculated
in grams of farnesene produced per gram of glucose consumed for
both strains EQ-0253 and EQ-0353,
Y .alpha. - farnesene / Glc = farnesene ( mg / L aqueous ) glucose
( mg / L aqueous ) . ##EQU00001##
TABLE-US-00014 TABLE 13 Mass yield of .alpha.-farnesene to
D-glucose Y.sub..alpha.-farnesene/glucose Yield Strains
(.times.10.sup.-4) (g/g) improvement EQ-0253 12.5 +9.6% EQ-0353
11.4
[0213] The increase in the mass yield of .alpha.-farnesene to
D-glucose observed was 9.6% for strain EQ-0253, compared with
control strain EQ-0353.
Example 3: Improvement of Citrate Production in S. cerevisiae
[0214] a) Inactivation of the ZWF1 Gene and the IDH1 Gene in a
Haploid Strain of Mating Type MAT a
[0215] Inactivation of the ZWF1 Gene
[0216] The coding phase of the hygromycin B resistance gene,
derived from the hphMX cassette (loxP-pAgTEF1-hph-tAgTEF1-loxP) and
contained on plasmid pUG75 (P30671)--Euroscarf), is amplified with
the oligonucleotides Sdzwf1 and Rdzwf1 (Table 14). This makes it
possible to generate a .DELTA.zwf1 PCR amplicon containing at its
ends homologous recombination sequences of the glucose-6-phosphate
dehydrogenase ZWF1 gene locus.
TABLE-US-00015 TABLE 14 Oligonucleotides Name Sequence Sdzwf1
AAGAGTAAATCCAATAGAATAGAAAACCACATAAGGCAAGA (SEQ ID
TGGGTAAAAAGCCTGAACTCACCG NO: 3) Rdzwf1
ATTTCAGTGACTTAGCCGATAAATGAATGTGCTTGCATTTT (SEQ ID
TTTATTCCTTTGCCCTCGGACG NO: 4) Sdpgk1
ACAGATCATCAAGGAAGTAATTATCTACTTTTTACAACAAA (SEQ ID
TATAAAACAATGGGTAAGGAAAAGACTCACGTTTC NO: 5) Rdpgk1
GGGAAAGAGAAAAGAAAAAAATTGATCTATCGATTTCAATT (SEQ ID
CAATTCAATTTAGAAAAACTCATCGAGCATCAAATGAAAC NO: 6) Sdidh1
TCTCCCTATCCTCATTCTTCTCCCTTTTCCTCCATAATTGT (SEQ ID
AAGAGAAAAATGGGTACCACTCTTGACGACACGG NO: 7) Rdidh1
AATTTGAACACACTTAAGTTGCAGAACAAAAAAAAGGGGAA (SEQ ID
TTGTTTTCATTAGGGGCAGGGCATGCTCATGTAGAGC NO: 8)
[0217] The underlined portion of the oligonucleotides corresponds
to the portion perfectly homologous to the sequence of the
selection gene, the rest of the sequence corresponding to the
regions adjacent to the coding phase of the target gene to be
deleted on the Saccharomyces cerevisiae genome.
[0218] The previously described strain CEN.PK 1605 (Mat a HISS
leu2-3.112 trp1-289 ura3-52 MAL.28c) derived from the commercial
strain CEN.PK 113-7D (GenBank: JRIV00000000) is transformed with
the .DELTA.zwf1 PCR fragment described above.
[0219] For the transformation reaction, strain CEN.PK 1605 is grown
in a volume of 50 mL of complex rich medium YPD (yeast extract
peptone dextrose, here 20 g/L glucose) at 30.degree. C. to an
optical density at 600 nm of 0.8. The cells are centrifuged for 5
minutes at 2,500 rpm at room temperature. The supernatant is
removed and the cells are resuspended in 25 mL of sterile water and
centrifuged again for 5 minutes at 2,500 rpm at room temperature.
After removing the supernatant, the cells are resuspended in 400
.mu.L of 100 mM sterile lithium acetate.
[0220] At the same time, a transformation mix is prepared in a 2 mL
tube as follows: 250 .mu.L of 50% PEG, 10 .mu.L of "carrier" DNA at
5 mg/mL, 36 .mu.L of 1 M lithium acetate, 10 .mu.L of purified PCR
reaction (deletion cassette) and 350 .mu.L of water.
[0221] The resuspended cells (50 .mu.L) are added to the
transformation mixture and incubated at 42.degree. C. for 40
minutes in a water bath. After incubation, the tube is centrifuged
for 1 minute at 5,000 rpm at room temperature and the supernatant
is discarded. The cells are resuspended in 2 mL of YPD (yeast
extract peptone dextrose) medium, transferred to a 14 mL tube and
incubated for 2 hours at 30.degree. C. at 200 rpm. The cells are
then centrifuged for 1 minute at 5,000 rpm at room temperature. The
supernatant is removed and the cells are resuspended in 1 mL of
sterile water and centrifuged again for 1 minute and resuspended in
100 .mu.L of sterile water and spread on YPD+HygromycinB (200
.mu.g/mL).
[0222] The colonies obtained were genotyped for the validation of
the deletion of the ZWF1 gene and referenced EQSC-002 (CEN.PK 1605
.DELTA.zwf1::hph).
[0223] Inactivation of the IDH1 Gene
[0224] Inactivation of this gene allows citrate to accumulate
(Rodriguez et al., Microb Cell Fact. 2016 Mar. 3; 15:48).
[0225] The coding phase of the nourseothricin resistance gene,
derived from the natMX cassette (loxP-pAgTEF1-nat-tAgTEF1-loxP)
contained on the plasmid (pUG74 (P30670)--Euroscarf) is amplified
with the oligonucleotides Sdidh1 and Rdidh1 (Table 13). This makes
it possible to generate a .DELTA.idh1 PCR amplicon containing at
its ends homologous recombination sequences of the isocitrate
dehydrogenase IDH1 subunit gene locus.
[0226] The strains previously described, EQSC-002 (CEN.PK 1605
.DELTA.zwf1::hph) and CEN.PK 1605 (Mat a HISS leu2-3.112 trp1-289
ura3-52 MAL.28c) derived from the commercial strain CEN.PK 113-7D
(GenBank: JRIV00000000) are transformed with the PCR fragment for
inactivation of the IDH1 gene.
[0227] For the transformation reaction, strains EQSC-002 and
CEN.PK1605 are grown in a volume of 50 mL of complex rich medium
YPD (yeast extract peptone dextrose, here 20 g/L glucose) at
30.degree. C. to an optical density at 600 nm of 0.8. The cells are
centrifuged for 5 minutes at 2,500 rpm at room temperature. The
supernatant is removed and the cells are resuspended in 25 mL of
sterile water and centrifuged again for 5 minutes at 2,500 rpm at
room temperature. After removing the supernatant, the cells are
resuspended in 400 .mu.L of 100 mM sterile lithium acetate.
[0228] At the same time, a transformation mix is prepared in a 2 mL
tube as follows: 250 .mu.L of 50% PEG, 10 .mu.L of "carrier" DNA at
5 mg/mL, 36 .mu.L of 1 M lithium acetate, 10 .mu.L of purified PCR
reaction (deletion cassette) and 350 .mu.L of water.
[0229] The resuspended cells (50 .mu.L) are added to the
transformation mixture and incubated at 42.degree. C. for 40
minutes in a water bath. After incubation, the tube is centrifuged
for 1 minute at 5,000 rpm at room temperature and the supernatant
is discarded. The cells are resuspended in 2 mL of YPD (yeast
extract peptone dextrose), transferred to a 14 mL tube and
incubated for 2 hours at 30.degree. C. at 200 rpm. The cells are
then centrifuged for 1 minute at 5,000 rpm at room temperature. The
supernatant is removed and the cells are resuspended in 1 mL of
sterile water and centrifuged again for 1 minute and resuspended in
100 .mu.L of sterile water and spread on YPD+HygromycinB 200
.mu.g/mL, 50 nourseothricin.
[0230] The colonies obtained were genotyped for the validation of
the deletion of the IDH1 gene and are called EQSC-003 (CEN.PK 1605
.DELTA.zwf1::hph, .DELTA.idh1::nat) and EQSC-005 (CEN.PK 1605
.DELTA.idh1::nat)
[0231] b) Inactivation of the PGK1 Gene in a Haploid Strain of
Mating Type MAT Alpha
[0232] The coding phase of the G418 resistance gene from the KanMX
cassette (loxP-pAgTEF1-kanMX-tAgTEF1-loxP) contained on plasmid
pUG6 (P30114)--Euroscarf is amplified with the oligonucleotides
Sdpgk1 and Rdpgk1 (Table 13) to generate a .DELTA.pgk1 PCR amplicon
containing at its ends homologous recombination sequences of the
3-phosphoglycerate kinase PGK1 gene locus.
[0233] Strain CEN.PK 1606 (Mat alpha HIS3 leu2-3.112 trp1-289
ura3-52 MAL.28c) derived from the commercial strain CEN.PK 113-7D
(GenBank: JRIV00000000) is transformed with the PCR fragment for
inactivation of the PGK1 gene.
[0234] For the transformation reaction, strain CEN.PK 1606 is grown
in a volume of 50 mL of complex rich medium YPD (yeast extract
peptone dextrose, here 20 g/L glucose) at 30.degree. C. to an
optical density at 600 nm of 0.8. The cells are centrifuged for 5
minutes at 2,500 rpm at room temperature. The supernatant is
removed and the cells are resuspended in 25 mL of sterile water and
centrifuged again for 5 minutes at 2,500 rpm at room temperature.
After removing the supernatant, the cells are resuspended in 400
.mu.L of 100 mM sterile lithium acetate.
[0235] At the same time, a transformation mix is prepared in a 2 mL
tube as follows: 250 .mu.L of 50% PEG, 10 .mu.L of "carrier" DNA at
5 mg/mL, 36 .mu.L of 1 M lithium acetate, 10 .mu.L of purified PCR
reaction (deletion cassette) and 350 .mu.L of water.
[0236] The resuspended cells (50 .mu.L) are added to the
transformation mixture and incubated at 42.degree. C. for 40
minutes in a water bath. After incubation, the tube is centrifuged
for 1 minute at 5,000 rpm at room temperature and the supernatant
is discarded. The cells are resuspended in 2 mL of YPGE (yeast
extract peptone 20 g/L glycerol, 30 g/L ethanol), transferred to a
14 mL tube and incubated for 2 hours at 30.degree. C. at 200 rpm.
The cells are then centrifuged for 1 minute at 5,000 rpm at room
temperature. The supernatant is removed and the cells are
resuspended in 1 mL of sterile water and centrifuged again for 1
minute and resuspended in 100 .mu.L of sterile water and spread
over YPGE+150 .mu.g/mL G418.
[0237] The colonies obtained were genotyped for the validation of
the deletion of the PGK1 gene and referenced EQSC-008 (CEN.PK 1605,
.DELTA.pgk1::kan).
[0238] c) Construction of a Strain in which IDH1, ZWF1 and PGK1
have been Inactivated by Crossing
[0239] The haploid strains of opposite mating types EQSC-003
(CEN.PK 1605 .DELTA.zwf1::hph, .DELTA.idh1::nat) and EQSC-008
(CEN.PK 1606 .DELTA.pgk1::kan) are grown overnight on agar
medium:YPD (yeast extract peptone dextrose) for strain EQSC-008 and
YPGE (yeast extract peptone glycerol ethanol) for strain EQSC003,
at 30.degree. C. Then the two strains are crossed by direct contact
on YPGE (yeast extract peptone glycerol ethanol) agar medium+150
.mu.g/mL G418+200 .mu.g/mL hygromycin B. The G418 and hygromycin B
double selection eliminates the two parental strains, only the MAT
a/MAT alpha, ZWF1/.DELTA.zwf1::hph, IDH1/.DELTA.idh1::nat,
PGK1/.DELTA.pgk1::kan diploid strains grow on this medium. An
isolated diploid clone from this crossing is collected. The
presence of the three cassettes .DELTA.zwf1::hph, .DELTA.idh1::nat,
.DELTA.pgk1::kan is validated by growth tests on YPGE (yeast
extract peptone glycerol ethanol) agar medium supplemented with 150
.mu.g/mL G418 or 200 .mu.g/mL hygromycin B or 50 .mu.g/mL
nourseothricin. The strain obtained is referenced EQSC-009 (CEN.PK
1607, MAT a/MAT alpha, ZWF1/.DELTA.zwf1::hph,
IDH1/.DELTA.idh1::nat, PGK1/.DELTA.pgk1::kan).
[0240] The previously described strain EQSC-009 (CEN.PK 1607, MAT
a/MAT alpha, ZWF1/.DELTA.zwf1::hph, IDH1/.DELTA.idh1::nat,
PGK1/.DELTA.pgk1::kan) is grown on YPGE (yeast extract peptone
glycerol ethanol) agar medium overnight at 30.degree. C. The cells
are then placed in liquid culture in a deficient medium
(Sporulation Medium, 1% potassium
acetate+leucine+uracil+tryptophan) to induce meiosis of the diploid
cells and thus lead to the formation of tetrads containing four
haploid spores. The tetrads are spread on YNB.GE medium (yeast
nitrogen base, glycerol, ethanol)+leucine+uracil+tryptophan+1 g/L
glutamic acid+20 mg/L methionine+40 mg/L cysteine and immediately
dissected (using a microdissector) to isolate the spores on the
same medium. The spores are germinated for several days at
30.degree. C. The genetic content of the haploid cells thus
obtained is tested by growth on selective media: YPGE (yeast
extract peptone glycerol ethanol) supplemented with 150 .mu.g/mL
G418 or 200 .mu.g/mL hygromycin B or 50 .mu.g/mL nourseothricin and
their mating type is tested by crossing with two tectrix strains of
mating type MAT a or MAT alpha. The colonies obtained are genotyped
for the validation of the deletion of the PGK1, IDH1, ZWF1 genes
and the absence of transcripts corresponding to these genes is
validated by real-time PCR after reverse transcription of
ribonucleic acids. One of the strains obtained is referenced
EQSC-004 (CEN.PK 1606 MAT alpha .DELTA.zwf1::hph, .DELTA.idh1::nat,
.DELTA.pgk1::kan)
[0241] d) Introduction of PRK-RuBisCO Enzymes
[0242] The six genes required for PRK-RuBisCO engineering (Table 15
below) are cloned on three plasmid vectors capable of autonomous
replication, with compatible origins of replication and each
carrying a different auxotrophic complementation gene, allowing the
selection of strains containing the three plasmid constructs (see
WO 2015107496). Two of these plasmids are single-copy with an
ARS/CEN origin of replication and the third is multicopy with a
2.mu. origin.
TABLE-US-00016 TABLE 15 Description of expression cassettes and
plasmid composition Codon Auxo- optimi- Termi- trophic GenBank
zation Promoter nator ori marker Plasmids RbcL BAD78320.1 Yes TDH3p
ADH1t 2.mu. URA3 pFPP45 RbcS BAD78319.1 Yes TEF1p PGK1t 2.mu. URA3
pFPP45 RbcX BAD80711.1 Yes TEF1p PGK1t ARS-CEN6 LEU2 pFPP56 GroES
U00096 No PGI1p CYC1t ARS-CEN6 LEU2 pFPP56 GroEL AP009048 No TDH3p
ADH1t ARS-CEN6 LEU2 pFPP56 PRK BAD78757.1 Yes Tet-OFF CYC1t
ARS416-CEN4 TRP1 pFPP20 Empty Tet-OFF ARS416-CEN4 TRP1 pCM185 Empty
TEF1p PGK1t 2.mu. URA3 pV51TEF Empty ARS-CEN6 LEU2 pFL36
[0243] According to the transformation protocol previously
described, strain EQSC-004 (CEN.PK 1606 .DELTA.zwf1::hph,
.DELTA.idh1::nat, .DELTA.pgk1::kan) was grown in a volume of 50 mL
of complex rich medium YPGE (yeast extract peptone glycerol
ethanol) at 30.degree. C. to an optical density at 600 nm of 0.8.
The cells are centrifuged for 5 minutes at 2,500 rpm at room
temperature. The supernatant is removed and the cells are
resuspended in 25 mL of sterile water and centrifuged again for 5
minutes at 2,500 rpm at room temperature. After removing the
supernatant, the cells are resuspended in 400 .mu.L of 100 mM
sterile lithium acetate.
[0244] At the same time, a transformation mix is prepared in a 2 mL
tube as follows: 250 .mu.L of 50% PEG, 10 .mu.L of "carrier" DNA at
5 mg/mL, 36 .mu.L of 1 M lithium acetate, 10 .mu.L (3 .mu.g) of a
combination of pFPP45+pFPP56+pFPP20 and 350 .mu.L of water.
[0245] The resuspended cells (50 .mu.L) are added to the
transformation mixture and incubated at 42.degree. C. for 40
minutes in a water bath. After incubation, the tube is centrifuged
for 1 minute at 5,000 rpm at room temperature and the supernatant
is discarded. The cells are resuspended in 2 mL of YPGE (yeast
extract peptone glycerol ethanol)+2 mg/L doxycycline, transferred
into a 14 mL tube and incubated for 2 hours at 30.degree. C. at 200
rpm. The cells are then centrifuged for 1 minute at 5,000 rpm at
room temperature. The supernatant is removed and the cells are
resuspended in 1 mL of sterile water and centrifuged again for 1
minute and resuspended in 100 .mu.L of sterile water and spread
over YNB.GE (yeast nitrogen base, glycerol, ethanol)+1 g/L glutamic
acid+20 mg/L methionine+40 mg/L cysteine+2 mg/L doxycycline. The
strain obtained is referenced: EQSC-006 (CEN.PK 1606
.DELTA.zwf1::hph, .DELTA.idh1::nat, .DELTA.pgk1::kan)
(pFPP45+pFPP56+pFPP20).
[0246] According to the transformation protocol previously
described, strain EQSC-005 (CEN.PK 1605 .DELTA.idh1::nat) was grown
in a volume of 50 mL of complex rich medium YPGE (yeast extract
peptone glycerol ethanol) at 30.degree. C. to an optical density at
600 nm of 0.8. The cells are centrifuged for 5 minutes at 2,500 rpm
at room temperature. The supernatant is removed and the cells are
resuspended in 25 mL of sterile water and centrifuged again for 5
minutes at 2,500 rpm at room temperature. After removing the
supernatant, the cells are resuspended in 400 .mu.L of 100 mM
sterile lithium acetate.
[0247] At the same time, a transformation mix is prepared in a 2 mL
tube as follows: 250 .mu.L of 50% PEG, 10 .mu.L of "carrier" DNA at
5 mg/mL, 36 .mu.L of 1 M lithium acetate, 10 .mu.L (3 .mu.g) of a
combination of pV51TEF+pFL36+pCM185 and 350 .mu.L of water.
[0248] The resuspended cells (50 .mu.L) are added to the
transformation mixture and incubated at 42.degree. C. for 40
minutes in a water bath. After incubation, the tube is centrifuged
for 1 minute at 5,000 rpm at room temperature and the supernatant
is discarded. The cells are resuspended in 2 mL of YPD (yeast
extract peptone dextrose), transferred to a 14 mL tube and
incubated for 2 hours at 30.degree. C. at 200 rpm. The cells are
then centrifuged for 1 minute at 5,000 rpm at room temperature. The
supernatant is removed and the cells are resuspended in 1 mL of
sterile water and centrifuged again for 1 minute and resuspended in
100 .mu.L of sterile water and spread on YNBD (yeast nitrogen base
dextrose)+2 mg/L doxycycline. The strain obtained is referenced:
EQSC-007 (CEN.PK 1605 .DELTA.idh1::nat) (pV51TEF+pFL36+pCM185).
[0249] d) Adaptation and Evolution Phase of Strains EQSC-006 and
EQSC-007
[0250] Adaptation of strains EQSC-006 and EQSC-007 to growth on YNB
(yeast nitrogen base) liquid medium with glucose and CO.sub.2.
[0251] Batch-mode cultures in Erlenmeyer flasks are carried out
with the appropriate culture medium and a 10% exogenous CO.sub.2
supply, in a shaking incubator (120 rpm, 30.degree. C.), with
inoculation at 0.05 OD 600 nm measured using an EON
spectrophotometer (BioTek Instruments). The strain of interest is
grown on YNB+CSM-LUW medium with 10 g/L glycerol and 7.5 g/L
ethanol, +50 mg/L glutamate under conditions where PRK expression
is not induced.
[0252] After obtaining a sufficient quantity of biomass, cultures
with a volume greater than or equal to 50 mL in Erlenmeyer flasks
of at least 250 mL are inoculated in order to adapt the strain to
the use of the PRK/RuBisCO engineering. This adaptation is carried
out on YNB+CSM-LUW culture medium with 20 g/L glucose, 50 mg/L
glutamate and an exogenous CO.sub.2 supply as described above.
[0253] After observation of a significant growth start, the strains
are adapted to a minimum mineral medium free of all amino acids
except those indicated below, and nitrogenous bases included in the
CSM-LUW, i.e. only YNB with, in final concentrations, 20 g/L
glucose, 1 g/L glutamate, 40 mg/L L-cysteine and 20 mg/L
L-methionine and an exogenous CO.sub.2 supply as described
above.
[0254] e) Production of Citrate in Erlenmeyer Flasks
[0255] Saccharomyces cerevisiae strain EQSC-006, with a deletion in
the glycolytic pathway at the PGK1 gene, in the oxidative part of
the pentose phosphate pathway and in the Krebs cycle, is grown to
produce citrate without CO.sub.2 loss, using PRK and RuBisCO. This
strain of interest is compared with a reference strain EQSC-007
producing citrate following inactivation of the IDH1 gene, without
deletion of PGK1 or ZWF1 or addition of PRK and RuBisCO.
[0256] Strains EQSC-006 (CEN.PK 1605 .DELTA.zwf1::hph,
.DELTA.idh1::nat, .DELTA.pgk1::kan, pFPP45+pFPP56+pFPP20) and
EQSC-007 (CEN.PK 1605 .DELTA.idh1::nat, pV51TEF+pFL36+pCM185) were
cultured in yeast nitrogen base (YNB) medium supplemented with 20
g/L D-glucose (YNB D20).
[0257] In order to establish the citrate to glucose mass yields, a
pre-culture containing 20 mL of culture medium was inoculated at
0.05 OD.sub.600 nm into a 250 mL baffled Erlenmeyer flask, shaken
at 120 rpm at 30.degree. C. From the first pre-culture, 50 mL of
medium was inoculated at 0.05 OD.sub.600 nm into a 250 mL
Erlenmeyer flask and shaken at 120 rpm, at 30.degree. C. The
culture was carried out in Erlenmeyer flasks (500 mL, baffled) from
the second pre-culture, inoculated at 0.05 OD.sub.600 nm into 100
mL of the same medium, at 30.degree. C., 120 rpm. Growth was
monitored by measuring turbidity at 600 nm.
[0258] For citrate quantification, 500 .mu.L of culture medium was
collected, centrifuged at 5,000 g, 5 min, 4.degree. C. The
supernatant was filtered (Minicart RC4, Sartorius 0.45 .mu.m) and
stored in a flask at -20.degree. C. before HPLC analysis (Thermo
Scientific UltiMate 3000 HPLC) coupled to a single quadrupole mass
spectrometer. Each sample (20 .mu.L) was injected into an Aminex
HPX-87H H.sup.+ column, 300 mm.times.7.8 mm (Bio-Rad, 125-0140). An
isocratic elution at a flow rate of 0.5 mL/min was carried out with
an aqueous solution of 0.037% formic acid (v/v) whose pH was
adjusted to 4.5 with ammonium hydroxide. The column oven
temperature was 65.degree. C. The mass spectrometry analytical
conditions were: negative electrospray mode, source temperature
450.degree. C., needle voltage 3 kV, cone voltage 50 V. A
seven-point external calibration was performed using a commercial
sodium citrate solution.
[0259] To quantify the glucose consumed by the strains, 500 .mu.L
of the culture medium was collected, at the same culture OD.sub.600
nm as for citrate quantification, centrifuged at 5,000 g, 5 min at
4.degree. C. The supernatant was filtered (Minicart RC4, Sartorius
0.45 .mu.m) and stored in a flask at -20.degree. C. The glucose
contained in this sample was quantified by HPLC-RI UltiMate 3000
(Thermo Scientific) equipped with a pump, an 8.degree. C.
refrigerated autosampler and a refractive index (RI) detector
(Precision Instruments IOTA 2). A Rezex ROA-Organic Acid H.sup.+
column (8%) 150.times.7.8 mm, 8 .mu.m particle size (Phenomenex,
00H-0138-KO) was used with a Carbo-H 4.times.3.0 mm pre-column. The
column oven temperature was 35.degree. C. and the flow rate was set
at 0.5 mL/min A 30 min isocratic elution was performed with an
aqueous mobile phase at 5 mM H.sub.2SO.sub.4. A volume of 20 .mu.L
was injected for each sample. The identification of the compounds
was based on the comparison of retention times with standards. The
external calibration included 10 points of variable glucose
concentration (0 to 20 g/L).
[0260] The Y.sub.citrate/Glc mass yield was calculated in grams of
citrate produced per gram of glucose consumed for both strains
EQSC-006 and EQSC-007,
Y c i t r a t e / G l c = citrate ( mg / L aqueous ) glucose ( mg /
Laqueous ) . ##EQU00002##
TABLE-US-00017 TABLE 16 Mass yield, citrate to D-glucose
Y.sub.citrate/glucose Yield Strains (.times.10.sup.-3) (g/g)
improvement EQSC-006 2.1 +19.5% EQSC-007 1.8
[0261] A 19.5% increase in the citrate to D-glucose mass yield was
observed for strain EQSC-006 compared with control strain
EQSC-007.
Example 4: Improvement of Glutamate Production in E. coli
[0262] Deletion of the alpha-ketoglutarate dehydrogenase gene
increases glutamate production (Usuda et al. J Biotechnol. 2010 May
3; 147(1):17-30. doi: 10.1016/j.jbiotec.2010.02.018).
[0263] In these examples, Escherichia coli strain K12 MG1655 with a
deleted sucA gene was used. This strain is derived from a gene
deletion bank (Baba et al. Mol Syst Biol. 2006; 2:2006.0008) in
Escherichia coli and supplied by the coli Genetic Stock Center
under the name JW0715-2 and with reference 8786. (JW0715-2: MG1655
.DELTA.sucA::Kan)
[0264] 4A] Improvement of Glutamate Production by Inactivation of
Glycolysis
[0265] a) Removal of the Selection Cassette by Specific
Recombination of FTR Regions by Flp Recombinase
[0266] In order to be able to reuse the same deletion strategy as
that used to construct strain JW0715-2 above (Rodriguez et al.,
2016), the selection cassette was deleted using a recombinase.
[0267] Plasmid p707-Flpe (provided in the Quick & Easy E. coli
Gene Deletion Red.RTM./ET.RTM. Recombination Kit by Gene Bridges)
is transformed by electroporation according to the kit protocol.
The cells are selected on LB agar supplemented with 0.2% glucose,
0.0003% tetracycline and added with 0.3% L-arabinose. A
counter-selection of the clones obtained is carried out by
verifying that they are no longer able to grow on the same medium
supplemented with 0.0015% kanamycin.
[0268] The strain obtained is called EQ.EC002: MG1655
.DELTA.sucA
[0269] b) Deletion of the Edd-Eda Operon Encoding the
Entner-Doudoroff Metabolic Pathway
[0270] The deletion of the edd-eda operon is performed by
homologous recombination and the use of the Quick & Easy E.
coli Gene Deletion Red.RTM./ET.RTM. Recombination Kit (Gene
Bridges) according to the supplier's protocol. [0271] 1.
Oligonucleotides designed to amplify an FRT-PKG-gb2-neo-FRT
resistance gene expression cassette and having a 5' sequence
homologous over 50 nucleotides to the adjacent regions of the
deletion locus, i.e. at positions 1932065-1932115 and
1934604-1934654 on the chromosome thus generating recombination
arms of the cassette on the bacterial genome on either side of the
entire operon. [0272] 2. The Escherichia coli K-12 strain EQ.EC002
is transformed by electroporation with plasmid pRedET according to
the kit protocol. The colonies obtained are selected on rich
complex medium LB agar with 0.2% glucose, 0.0003% tetracycline.
[0273] 3. Transformation of the amplicon obtained in the first step
in the presence of RedET recombinase, induced by 0.3% arabinose in
liquid LB for 1 h. To that end, a second electroporation of the
cells expressing RedET by the deletion cassette is performed and
the colonies are selected on LB agar supplemented with 0.2%
glucose, 0.0003% tetracycline and added with 0.3% L-arabinose and
0.0015% kanamycin. [0274] 4. Plasmid p707-Flpe (provided in the
Quick & Easy E. coli Gene Deletion Red.RTM./ET.RTM.
Recombination Kit by Gene Bridges) is transformed by
electroporation according to the kit protocol. The cells are
selected on LB agar supplemented with 0.2% glucose, 0.0003%
tetracycline and added with 0.3% L-arabinose. A counter-selection
of the clones obtained is carried out by verifying that they are no
longer able to grow on the same medium supplemented with 0.0015%
kanamycin. [0275] 5. The strain obtained is called EQ.EC003: MG1655
.DELTA.sucA .DELTA.edd-eda
[0276] c) Deletion of the gapA Gene
[0277] The deletion of the gapA gene is performed by homologous
recombination and the use of the Quick & Easy E. coli Gene
Deletion Red.RTM./ET.RTM. Recombination Kit (Gene Bridges)
according to the supplier's protocol. [0278] 1. Oligonucleotides
designed to amplify an FRT-PKG-gb2-neo-FRT resistance gene
expression cassette and having a 5' sequence homologous over 50
nucleotides to the adjacent regions of the deletion locus, i.e. the
coding phase of the gene (gapA) (GenBank: X02662.1) thus generating
recombination arms of the cassette on the bacterial genome. [0279]
2. The Escherichia coli K-12 strain EQ.EC003 is transformed by
electroporation with plasmid pRedET according to the kit protocol.
The colonies obtained are selected on rich complex medium LB agar
with 0.2% glucose, 0.0003% tetracycline. [0280] 3. Transformation
of the amplicon obtained in the first step in the presence of RedET
recombinase which will be induced by 0.3% arabinose in liquid LB
for 1 h. To that end, a second electroporation of the cells
expressing RedET by the deletion cassette is performed and the
colonies are selected on LB agar supplemented with 0.2% glycerol
and 0.3% pyruvate, 0.0003% tetracycline and added with 0.3%
L-arabinose and 0.0015% kanamycin.
[0281] Deletions are verified by genotyping and sequencing and the
name of the strains obtained is [0282] EQ.EC002: MG1655 .DELTA.sucA
[0283] EQ.EC003: MG1655 .DELTA.sucA .DELTA.edd-eda [0284] EQ.EC004:
MG1655 .DELTA.sucA .DELTA.edd-eda .DELTA.gapA::kan
[0285] d) Insertion of the Engineering Required for CO.sub.2
Fixation
[0286] For the recombinant expression of the different components
of a type I RuBisCO in E. coli, the genes described in Table 17
below are cloned as a synthetic operon containing the genes
described in Table 18 below.
TABLE-US-00018 TABLE 17 Genes encoding a PRK and type I RuBisCO
system Genes GenBank Organism rbcL BAD78320.1 Synechococcus
elongatus rbcS BAD78319.1 Synechococcus elongatus rbcX BAD80711.1
Synechococcus elongatus Prk BAD78757.1 Synechococcus elongatus
TABLE-US-00019 TABLE 18 Composition of the expression cassettes
Structure of the synthetic operon in vector pZA11 Plasmid Gene A
RBS1 Gene B RBS2 Gene C RBS3 Gene D RBS4 Gene E pZA11 pEQEC005 rbcS
D rbcL B rbcX F pEQEC006 rbcS D rbcL B rbcX F prk pEQEC008 prk
[0287] To control the expression level of these genes, ribosome
binding sequences (RBS) presented in Table 19 below, with variable
translation efficiencies (Levin-Karp et al., ACS Synth Biol. 2013
Jun. 21; 2(6):327-36. doi: 10.1021/sb400002n; Zelcbuch et al.,
Nucleic Acids Res. 2013 May; 41(9):e98) are inserted between the
coding phase for each gene. The succession of each coding phase
interspersed by an RBS sequence is constructed by successive
insertions into a pZA11 vector (Expressys) that contains a PLtetO-1
promoter, a p15A origin of replication and an ampicillin resistance
gene.
TABLE-US-00020 TABLE 19 RBS intercistronic sequences Name RBS
sequences A (SEQ ID NO: 9) AGGAGGTTTGGA B (SEQ ID NO: 10)
AACAAAATGAGGAGGTACTGAG C (SEQ ID NO: 11) AAGTTAAGAGGCAAGA D (SEQ ID
NO: 12) TTCGCAGGGGGAAG E (SEQ ID NO: 13) TAAGCAGGACCGGCGGCG F (SEQ
ID NO: 14) CACCATACACTG
[0288] Several strains are produced by electroporating the
different vectors presented according to the above plan
[0289] EQ.EC 005.fwdarw.(EQ.EC 003+pZA11): MG1655 .DELTA.sucA
.DELTA.edd-eda
[0290] EQ.EC 006.fwdarw.(EQ.EC 004+pEQEC005): MG1655 .DELTA.sucA
.DELTA.edd-eda .DELTA.gapA::kan (RuBisCO)
[0291] EQ.EC 007.fwdarw.(EQ.EC 004+pEQEC006): MG1655 .DELTA.sucA
.DELTA.edd-eda .DELTA.gapA::kan (RuBisCO+PRK)
[0292] EQ.EC 009.fwdarw.(EQ.EC 004+pEQEC008): MG1655 .DELTA.sucA
.DELTA.edd-eda .DELTA.gapA::kan (PRK)
[0293] Clones are selected on LB medium supplemented with 2 g/L
glycerol and 5 g/L pyruvate and with 100 mg/L ampicillin. After
obtaining a sufficient quantity of biomass, cultures with a volume
greater than or equal to 50 mL in a minimum 250 mL Erlenmeyer flask
are inoculated in order to adapt the strain to the use of the
PRK/RuBisCO engineering. This adaptation is carried out on LB
culture medium with 2 g/L glucose, and an exogenous CO.sub.2 supply
at 37.degree. C. as described above.
[0294] e) Glutamate Production
[0295] For glutamate production, cells from 500 mL of LB culture
are inoculated into 20 mL of MS medium (40 g/L glucose, 1 g/L
MgSO.sub.4.7H.sub.2O, 20 g/L (NH.sub.4).sub.2SO.sub.4, 1 g/L
KH.sub.2PO.sub.4, 10 mg/L FeSO.sub.4.7H.sub.2O, 10 mg/L
MnSO.sub.4.7H.sub.2O, 2 g/L yeast extract, 30 g/L CaCO.sub.3, 100
mg/L ampicillin at a pressure of 0.1 atmosphere CO.sub.2.
[0296] Residual glutamate and glucose are measured with a
bioanalyzer (Sakura Seiki). The carbon yield Y.sub.p/s is
calculated in grams of glutamate produced per gram of glucose
consumed.
[0297] This yield increases significantly by 10% for strains EQ.EC
007 (RuBisCO+PRK) compared with the control strains EQ.EC 005
(empty), EQ.EC 006 (RuBisCO only). The control strain EQ.EC 009
(PRK alone) is not viable.
[0298] 4B] Improvement of Production by Inactivation of Glycolysis
and of the Pentose Phosphate Oxidative Pathway
[0299] a) Removal of the Selection Cassette by Specific
Recombination of FTR Regions by Flp Recombinase
[0300] This step is performed in the same way as example 4A]
above.
[0301] The strain obtained is called EQ.EC002: MG1655
.DELTA.sucA
[0302] b) Deletion of the zwf Gene
[0303] The deletion of the zwf gene (GeneID: 946370) is performed
by homologous recombination and the use of the Quick & Easy E.
coli Gene Deletion Red.RTM./ET.RTM. Recombination Kit (Gene
Bridges) according to the supplier's protocol, as detailed in
Example 4A].
[0304] The strain obtained is called EQ.EC010: MG1655 .DELTA.sucA
.DELTA.zwf
[0305] c) Deletion of the gapA Gene
[0306] The deletion of the gapA gene in the Escherichia coli K-12
strain EQ.EC010 is performed by homologous recombination and the
use of the Quick & Easy E. coli Gene Deletion Red.RTM./ET.RTM.
Recombination Kit (Gene Bridges) according to the supplier's
protocol, as detailed in Example 4A].
[0307] Deletions are verified by genotyping and sequencing and the
name of the strains obtained is: [0308] EQ.EC002: MG1655
.DELTA.sucA [0309] EQ.EC010: MG1655 .DELTA.sucA .DELTA.zwf [0310]
EQ.EC011: MG1655 .DELTA.sucA .DELTA.zwf .DELTA.gapA
[0311] d) Insertion of the Engineering Required for CO.sub.2
Fixation
[0312] For the recombinant expression of the different components
of the functional PRK/RuBisCO system in E. coli, the genes
described in Table 20 and encoding a type I RuBisCO, a
phosphoribulokinase, a chaperone and a carbonic anhydrase are
cloned as a synthetic operon containing the genes described above
(Table 21).
TABLE-US-00021 TABLE 20 Genes encoding a type I RuBisCO, a
phosphoribulokinase and a carbonic anhydrase Genes GenBank Organism
rbcL BAD78320.1 Synechococcus elongatus rbcS BAD78319.1
Synechococcus elongatus rbcX BAD80711.1 Synechococcus elongatus Prk
BAD78757.1 Synechococcus elongatus icfA WP_011378036.1
Synechococcus elongatus
TABLE-US-00022 TABLE 21 Plasmid names and expression cassette
composition Structure of the synthetic operon in vector pZA11
Plasmid Gene A RBS1 Gene B RBS2 Gene C RBS3 Gene D RBS4 Gene E
pZA11 pEQEC006 rbcS D rbcL B rbcX F prk pEQEC007 rbcS D rbcL B rbcX
F prk A icfA
[0313] To control the expression level of these genes, ribosome
binding sequences (RBS) presented in Table 17 (see Example 4A]),
with variable translation efficiencies (Levin-Karp et al., ACS
Synth Biol. 2013 Jun. 21; 2(6):327-36. doi: 10.1021/sb400002n;
Zelcbuch et al., Nucleic Acids Res. 2013 May; 41(9):e98) are
inserted between the coding phase of each gene. The succession of
each coding phase interspersed by an RBS sequence is constructed by
successive insertions into a pZA11 vector (Expressys) that contains
a PLtetO-1 promoter, a p15A origin of replication and an ampicillin
resistance gene. The addition of a carbonic anhydrase (icfA) also
allows an inter-conversion of bicarbonate ions into available
CO.sub.2 molecules and improves the efficiency of RuBisCO.
[0314] Several strains are produced by electroporating the
different vectors presented according to the plan below
[0315] EQ.EC 012.fwdarw.(EQ.EC 002+pZA11): MG1655 .DELTA.sucA
[0316] EQ.EC 014.fwdarw.(EQ.EC 011+pEQEC006): MG1655 .DELTA.sucA
.DELTA.zwf .DELTA.gapA (RuBisCO+PRK)
[0317] EQ.EC 015.fwdarw.(EQ.EC 011+pEQEC007): MG1655 .DELTA.sucA
.DELTA.zwf .DELTA.gapA (RuBisCO+PRK+carbonic anhydrase)
[0318] After transformation, clones are selected on LB glycerol,
pyruvate medium supplemented with 100 mg/L ampicillin. An
adaptation and evolution phase of the strains with PRK and RuBisCO
engineering is performed as described in Example 4A].
[0319] e) Glutamate Production
[0320] For glutamate production, cells from 500 mL of LB culture
are inoculated into 20 mL of MS medium (40 g/L glucose, 1 g/L
MgSO.sub.4.7H.sub.2O, 20 g/L (NH4).sub.2SO.sub.4, 1 g/L
KH.sub.2PO.sub.4, 10 mg/L FeSO.sub.4.7H.sub.2O, 10 mg/L
MnSO.sub.4.7H.sub.2O, 2 g/L yeast extract, 30 g/L CaCO.sub.3, 100
mg/L ampicillin at a pressure of 0.1 atmosphere CO.sub.2.
[0321] Residual glutamate and glucose are measured with a
bioanalyzer (YSI Inc.). The carbon yield Y.sub.p/s is calculated in
grams of glutamate produced per gram of glucose consumed.
[0322] This yield increases significantly by 15% for strains EQ.EC
014 (RuBisCO+PRK) and EQ.EC 015 (RuBisCO+PRK+carbonic anhydrase)
compared with the control strains EQ.EC 012 (empty).
[0323] 4C] Improvement of Production by Inactivation of Glycolysis
and Oxidative Pentose Phosphate Pathway, and Overexpression of
Pyruvate Decarboxylase and Glutamate Dehydrogenase.
[0324] a) Removal of the Selection Cassette by Specific
Recombination of FTR Regions by Flp Recombinase
[0325] This step is performed in the same way as example 4A]
above.
[0326] The strain obtained is called EQ.EC002: MG1655
.DELTA.sucA
[0327] b) Deletion of the zwf Gene
[0328] The deletion of the zwf gene (GeneID: 946370) is performed
by homologous recombination and the use of the Quick & Easy E.
coli Gene Deletion Red.RTM./ET.RTM. Recombination Kit (Gene
Bridges) according to the supplier's protocol, as detailed in
Example 4A]. The strain obtained is called EQ.EC010: MG1655
.DELTA.sucA .DELTA.zwf
[0329] c) Deletion of the gapA Gene
[0330] The deletion of the gapA gene in the Escherichia coli K-12
strain EQ.EC010 is performed by homologous recombination and the
use of the Quick & Easy E. coli Gene Deletion Red.RTM./ET.RTM.
Recombination Kit (Gene Bridges) according to the supplier's
protocol, as detailed in Example 4A]. Deletions are verified by
genotyping and sequencing and the name of the strains obtained is:
[0331] EQ.EC002: MG1655 .DELTA.sucA [0332] EQ.EC010: MG1655
.DELTA.sucA .DELTA.zwf [0333] EQ.EC011: MG1655 .DELTA.sucA
.DELTA.zwf .DELTA.gapA
[0334] d) Insertion of the Engineering Necessary for CO.sub.2
Fixation
[0335] For the recombinant expression of the different components
of the functional PRK/RuBisCO system in E. coli, the genes
described in Table 22 and encoding a type II RuBisCO, a
phosphoribulokinase and a carbonic anhydrase are cloned as a
synthetic operon containing the genes described above (Table
23).
TABLE-US-00023 TABLE 22 Genes encoding a type II RuBisCO, a
phosphoribulokinase, a carbonic anhydrase, a glutamate
dehydrogenase and a pyruvate carboxylase Genes GenBank Organism
cbbM YP_427487.1 Rhodospirillum rubrum Prk BAD78757.1 Synechococcus
elongatus CA YP_427143.1 Rhodospirillum rubrum gdhA NP_416275.1
Escherichia coli K-12 pycA NP_389369.1 Bacillus subtilis
TABLE-US-00024 TABLE 23 Plasmid names and expression cassette
composition Structure of the synthetic operon in vector pZA11
Plasmid Gene A RBS1 Gene B RBS2 Gene C RBS3 Gene D RBS4 Gene E
pZA11 pEQEC009 cbbM B gdhA C pycA E prk pEQEC010 cbbM B gdhA C pycA
E prk D CA pEQEC011 B gdhA C pycA
[0336] To control the expression level of these genes, ribosome
binding sequences (RBS) presented in Table 17 (see Example 4A]),
with variable translation efficiencies, are inserted between the
coding phase of each gene. The succession of each coding phase
interspersed by an RBS sequence is constructed by successive
insertions into a pZA11 vector (Expressys) that contains a PLtetO-1
promoter, a p15A origin of replication and an ampicillin resistance
gene. The addition of a glutamate dehydrogenase (gdhA) and a
pyruvate carboxylase (pycA) allows a better production of glutamic
acid. The addition of a carbonic anhydrase (CA) also allows an
interconversion of bicarbonate ions into available CO.sub.2
molecules and improves the efficiency of RuBisCO.
[0337] Several strains are produced by electroporating the
different vectors presented according to the plan below:
[0338] EQ.EC 016.fwdarw.(EQ.EC 002+pEQEC011): MG1655 .DELTA.sucA
(glutamate dehydrogenase+pyruvate carboxylase)
[0339] EQ.EC 017.fwdarw.(EQ.EC 011+pEQEC009): MG1655 .DELTA.sucA
.DELTA.zwf .DELTA.gapA (RuBisCO+PRK+glutamate
dehydrogenase+pyruvate carboxylase)
[0340] EQ.EC 018.fwdarw.(EQ.EC 011+pEQEC010): MG1655 .DELTA.sucA
.DELTA.zwf .DELTA.gapA (RuBisCO+PRK+carbonic anhydrase+glutamate
dehydrogenase+pyruvate carboxylase+carbonic anhydrase)
[0341] After transformation, clones are selected on LB glycerol,
pyruvate medium supplemented with 100 mg/L ampicillin. An
adaptation and evolution phase of the strains with PRK and RuBisCO
engineering is performed as described in Example 4A].
[0342] e) Glutamate Production
[0343] For glutamate production, cells from 500 mL of LB culture
are inoculated into 20 mL of MS medium (40 g/L glucose, 1 g/L
MgSO.sub.4.7H.sub.2O, 20 g/L (NH.sub.4).sub.2SO.sub.4, 1 g/L
KH.sub.2PO.sub.4, 10 mg/L FeSO.sub.4.7H.sub.2O, 10 mg/L
MnSO.sub.4.7H.sub.2O, 2 g/L yeast extract, 30 g/L CaCO.sub.3, 100
mg/L ampicillin at a pressure of 0.1 atmosphere CO.sub.2.
[0344] Residual glutamate and glucose are measured with a
bioanalyzer (YSI Inc.). The carbon yield Y.sub.p/s is calculated in
grams of glutamate produced per gram of glucose consumed.
[0345] This yield increases significantly by 15% for strains EQ.EC
017 and EQ.EC 018 compared with the control strain EQ.EC 016.
Example 5: Improvement of Polyhydroxybutyrate Production in C.
necator
[0346] The increase in reducing power obtained through the genetic
modifications proposed according to the invention may also have a
considerable gain over existing metabolic pathways.
[0347] This is the case for the bacterial strain Cupriavidus
necator ATCC 17699 which naturally produces polyhydroxybutyrate
(PHB). This bacterium is capable of developing under both
autotrophic and heterotrophic conditions. The deletion of the gapA
gene (glyceraldehyde-3-phosphate dehydrogenase NC_008313.1) diverts
the metabolic flux to the pentose phosphate pathway and increases
the pool of NADPH reduced nucleotides thus increasing the PHB
production yield.
[0348] This C. necator H16 strain has a megaplasmid pHG1 and two
chromosomes. The deletion of the gapA gene is performed by
generating a vector containing the Bacillus subtilis suicide gene
sacB for Gram-negative bacteria (Quandt et al., Gene. 1993 May 15;
127(1):15-21; Lindenkamp et al., Appl Environ Microbiol. 2010
August; 76(16):5373-82 and Appl Environ Microbiol. 2012 August;
78(15):5375-83).
[0349] a) Inactivation of the Entner-Doudoroff Metabolic
Pathway
[0350] Two PCR amplicons corresponding to adjacent regions of the
edd and eda genes (upstream of edd and downstream of eda) are
cloned by restriction according to the procedure described in
Srinivasan et al. (Appl Environ Microbiol. 2002 December;
68(12):5925-32), in plasmid pJQ200mp18Cm.
[0351] The modified plasmid pJQ200mp18Cm::.DELTA.edd-eda is then
transformed into an E. coli strain S17-1 by the calcium chloride
transformation method. The transfer of genetic material into C.
necator is done by conjugation by depositing on agar a spot of C.
necator culture on a dish containing a cell monolayer of S17-1
bacteria. Selection is made on nutrient broth (NT) medium at
30.degree. C. in the presence of 10% sucrose for purposes of
selection (Hogrefe et al., J Bacteriol. 1984 April; 158(1):43-8)
and validated on a mineral medium containing 50 .mu.g/mL
chloramphenicol.
[0352] The deletions are validated by genotyping and sequencing.
The resulting strain EQCN_002 therefore has deletions of the genes
of the Entner-Doudoroff metabolic pathway edd-eda. EQCN_002: H16
.DELTA.edd-eda.
[0353] b) Inactivation of the Glycolysis Pathway
[0354] Two PCR amplicons corresponding to adjacent regions of the
gapA gene are cloned by restriction according to the procedure
described in Lindenkamp et al. 2012, in plasmid pjQ200mp18Tc.
[0355] The modified plasmid pjQ200mp18Tc::.DELTA.gapA is then
transformed into an E. coli strain S17-1 by the calcium chloride
transformation method. The transfer of genetic material is done by
conjugation by depositing on agar a spot of C. necator culture on a
plate containing a cell monolayer of S17-1 bacteria. Selection is
made on nutrient broth (NT) medium at 30.degree. in the presence of
10% sucrose for purposes of selection (Hogrefe et al., J Bacteriol.
1984 April; 158(1):43-8) and validated on a mineral medium
containing 25 .mu.g/mL tetracycline.
[0356] The deletions are validated by genotyping and sequencing.
The strain obtained, EQCN_003, therefore has a deletion of the gapA
gene. EQCN_003: H16 .DELTA.edd-eda .DELTA.gapA.
[0357] Strain EQCN_003, with a deletion in the glycolytic pathway
at the gapA gene and in the Entner-Doudoroff pathway at the edd-eda
genes, is grown to improve PHB production yield by fixing exogenous
CO.sub.2 via the use of the PRK and RuBisCO enzymes.
[0358] b) Production of PHB in a Bioreactor
[0359] The inoculum from a frozen stock is spread on solid medium
at a rate of 50 to 100 .mu.L from a cryotube incubated at
30.degree. C. for 48 to 96 h in the presence of fructose. The
expression of genes encoding RuBisCO and PRK are maintained in C.
necator under heterotrophic aerobic conditions (Rie Shimizu et al.,
Sci Rep. 2015; 5: 11617. Published online 2015 Jul. 1).
[0360] Batch cultures in Erlenmeyer flasks (10 mL in 50 mL, then 50
mL in 250 mL) are carried out with the appropriate culture medium,
in 20 g/L fructose and a 10% exogenous CO.sub.2 supply in a shaking
incubator (100-200 rpm, 30.degree. C.), with a minimum inoculation
of 0.01.
[0361] The strain of interest EQCN_003 improving PHB production
yield is compared with a reference strain H16 naturally
accumulating PHB under heterotrophic conditions in the presence of
a nutritional limitation.
[0362] The productivity of the strains is compared in bioreactors.
Cultures carried out in bioreactors are seeded from solid and/or
liquid amplification chains in Erlenmeyer flasks under the
conditions described above. The bioreactors, of type My-control
(Applikon Biotechnology, Delft, Netherlands) 750 mL or Biostat B
(Sartorius Stedim, Gottingen, Germany) 2.5 L, are seeded at a
density equivalent to 0.01 OD.sub.620 nm.
[0363] The accumulation of PHB is decoupled from growth. The
culture is regulated at 30.degree. C., aeration is between 0.1 VVM
(gas volume/liquid volume/min) and 1 VVM in order to maintain a
minimum dissolved oxygen concentration above 20% (30.degree. C., 1
bar), shaking is adapted according to the scale of the bioreactor
used. The inlet gas flow consists of air optionally supplemented
with CO.sub.2. CO.sub.2 supplementation is between 1% and 10%. The
pH is adjusted to 7 with a 14% or 7% ammonia solution. The
fed-batch culture method allows a supply of non-limiting carbon
substrate combined with a limitation of phosphorus or nitrogen,
while maintaining a constant carbon/phosphorus or carbon/nitrogen
ratio. PHB extraction and quantification are performed according to
the method of Brandl et al. (Appl Environ Microbiol. 2013 July;
79(14):4433-9). The protocol consists in adding 1 mL of chloroform
to 10 mg of lyophilized cells, followed by 850 .mu.L of methanol
and 150 .mu.L of sulfuric acid. The mixture is heated for 2.5 h at
100.degree. C., cooled and 500 .mu.L of water is added. The two
phases are separated by centrifugation and the organic phase is
dried by adding sodium sulfate The samples are filtered and
analyzed as described by Muller et al. (Appl Environ Microbiol.
2013 July; 79(14):4433-9).
[0364] A comparison of wild-type C. necator H16 cultures and strain
EQCN_003: H16 .DELTA.edd-eda .DELTA.gapA shows a 5% increase in
carbon yield, corresponding here to the ratio grams of PHB per gram
of fructose consumed.
Example 6: Improvement of GABA Production in E. coli
[0365] An Escherichia coli K-12 strain, genetically modified to
increase the yield of its glutamate production according to example
4B], can also be modified to allow the constitutive expression of a
glutamate decarboxylase gadB (Gene ID: 946058) and thus increase
the production yield of .gamma.-aminobutyric acid.
[0366] The deletion of the alpha-ketoglutarate dehydrogenase gene
also increases glutamate production (Usuda et al. J Biotechnol.
2010 May 3; 147(1):17-30. doi: 10.1016/j.jbiotec.2010.02.018).
[0367] In this example, the following strains are used, obtained
from example 4B]: [0368] EQ.EC002: MG1655_.DELTA.sucA [0369]
EQ.EC010: MG1655_.DELTA.sucA .DELTA.zwf [0370] EQ.EC011: MG1655
.DELTA.sucA .DELTA.zwf .DELTA.gapA
[0371] a) Constitutive Overexpression of the gadB Gene
[0372] Overexpression of the gadB gene is subcloned into a
bacterial expression vector pZE21MCS (EXPRESSYS). This vector has a
ColE1 origin of replication and a kanamycin antibiotic resistance
gene.
[0373] Rapidly, the coding phase of the gadB gene (Gene ID: 946058)
is amplified from the genome of strain MG1655 .DELTA.sucA with
primers homologous to the Escherichia coli K-12 genome covering
positions 1570595 to 1570645 and 1572095 to 1572045. Each of these
primers is coupled to floating sequences homologous over 18
nucleotides at the ends of the fragment obtained by amplifying
vector pZE21MCS excluding the multiple cloning site. The two
amplicons are combined according to the protocol of the
In-Fusion.RTM. HD Cloning Kit User Manual--Clontech to form plasmid
pEQEC030 allowing the constitutive overexpression of the gadB
gene.
[0374] b) Insertion of the Engineering Required for CO.sub.2
Fixation
[0375] For the recombinant expression of the different components
of a functional type I RuBisCO in E. coli, the genes described in
Table 17 (Example 4A]), are cloned as a synthetic operon following
the construction structure described in Table 22.
[0376] Assembly of the Different Vectors
[0377] The coding sequences (CDS) of the genes described in Table
24 are amplified and assembled into blocks according to the
protocol provided with the NEBuilder.RTM. HiFi DNA Assembly Master
Mix Kit (E2321) so as to obtain three integration blocks described
in Table 24. Each block is then amplified according to the protocol
of the In-Fusion.RTM. HD Cloning Kit User Manual--Clontech to form
the plasmids described below in Table 24.
TABLE-US-00025 TABLE 24 Composition of expression cassettes
Structure of the synthetic operon in vector pZA11 Block I Block II
Block III Plasmid CDS A RBS1 CDS B RBS2 CDS C RBS3 CDS D pZA11
pEQEC006 rbcS D rbcL B rbcX F prk
[0378] To control the expression level of these genes, ribosome
binding sequences (RBS) presented in Table 19 (Example 4B]), with
variable translation efficiencies (Levin-Karp et al., ACS Synth
Biol. 2013 Jun. 21; 2(6):327-36. doi: 10.1021/sb400002n; Zelcbuch
et al., Nucleic Acids Res. 2013 May; 41(9):e98) are inserted
between the coding phase for each gene. The succession of each
coding phase interspersed by an RBS sequence is constructed by
successive insertions into a pZA11 vector (Expressys) that contains
a PLtetO-1 promoter, a p15A origin of replication and an ampicillin
resistance gene. The addition of a glutamate decarboxylase (gadB)
also allows a conversion of glutamate to gamma-aminobutyrate
(GABA).
[0379] Several strains are produced by electroporating the
different vectors presented according to the plan below [0380]
EQ.EC 013.fwdarw.(EQ.EC 002+pZA11+pEQ030): MG1655
.DELTA.sucA+(gadB) [0381] EQ.EC 020.fwdarw.(EQ.EC
011+pEQ030+pEQEC006): MG1655 .DELTA.sucA .DELTA.zwf
.DELTA.gapA+(gadB)+(RuBisCO+PRK)
[0382] After transformation, clones are selected on LB glycerol,
pyruvate medium supplemented with 100 mg/L ampicillin and 30 mg/L
kanamycin. An adaptation and evolution phase of the strains with
PRK and RuBisCO engineering is performed as described in Example
4A].
[0383] c) GABA Production
[0384] For the production of GABA, cells from 500 mL of LB culture
are inoculated into 20 mL of MS medium (40 g/L glucose, 1 g/L
MgSO.sub.4.7H.sub.2O, 20 g/L (NH.sub.4).sub.2SO.sub.4, 1 g/L
KH.sub.2PO.sub.4, 10 mg/L FeSO.sub.4.7H.sub.2O, 10 mg/L
MnSO.sub.4.7H.sub.2O, 2 g/L yeast extract, 30 g/L CaCO.sub.3, 100
mg/L ampicillin and 30 mg/L kanamycin at a pressure of 0.1
atmosphere CO.sub.2, at 30.degree. C. at pH 3.5.
[0385] The GABA concentration is measured by high-performance
liquid chromatography (HPLC), using an OptimaPak C18 column
(4.6.times.150 mm, RS Tech Corporation, Daejeon, Korea). The
samples are centrifuged at 12,000 rpm for 5 minutes, 100 .mu.L of
the supernatant transferred into a new Eppendorf tube. The
following reagents are added to these tubes: 200 .mu.L of 1 M
sodium bicarbonate buffer (pH 9.8), 100 .mu.L of 80 g/L dansyl
chloride in acetonitrile and 600 .mu.L of double-distilled water.
The mixture is incubated at 80.degree. C. for 40 minutes. The
reaction is stopped by adding 100 .mu.L of 2% acetic acid. The
mixture is centrifuged at 12,000 rpm for 5 minutes. The supernatant
is then filtered through a 0.2 .mu.m Millipore filter and analyzed
by HPLC on an Agilent system using a UV detector. Derivatized
samples are separated using a binary non-linear gradient using
eluent A [tetrahydrofuran/methanol/sodium acetate 50 mM at pH 6.2
(5: 75: 420, by volume)] and eluent B (methanol). Residual glucose
is measured with a bioanalyzer (YSI Inc.).
[0386] The carbon yield Y.sub.p/s is calculated in grams of GABA
produced per gram of glucose consumed.
[0387] This yield increases significantly by 15% for strain EQ.EC
020 .DELTA.sucA .DELTA.zwf .DELTA.gapA (RuBisCO+PRK)+(GadB)
compared with the control strains EQ.EC 013 .DELTA.sucA (GadB).
Example 7: Improvement of Succinate and Oxalate Production in E.
coli
[0388] An Escherichia coli K-12 strain, genetically modified to
allow constitutive expression of a glyoxylate dehydrogenase
FPGLOXDH1 (Gene ID: 946058) from Fomitopsis palustris, to reduce
expression of the icd gene (Gene ID: 945702), and to inactivate the
aceB (GeneID 948512) and sdhA (Gene ID: 945402) genes, would
increase succinate and oxalic acid production yield.
[0389] The reduction in isocitrate dehydrogenase (icd) expression
allows the metabolic flux to be redirected to the glyoxylic shunt.
Inactivation of malate synthase (aceB) and succinate dehydrogenase
(sdhA) prevents the glyoxylate and succinate, respectively,
produced from being re-consumed. Deletion of the succinate
dehydrogenase gene increases succinate production under aerobic
conditions (Yang et al., Microbiol res. 2014 May-June;
169(5-6):432-40). Deletion of the malate synthase gene allows the
accumulation of glyoxylate which will be converted to oxalate by
the constitutive expression of glyoxylate dehydrogenase.
[0390] In this example, an Escherichia coli K-12 strain MG1655 in
which the sdhA gene has been deleted is used. This strain is
derived from a gene deletion bank (Baba et al. Mol Syst Biol. 2006;
2:2006.0008) in Escherichia coli K-12 and supplied by the coli
Genetic Stock Center under the name JW0715-2 and with reference
8302. (JW0713-1: MG1655 .DELTA.sdhA::Kan).
[0391] a) Removal of the Selection Cassette by Specific
Recombination of FTR Regions by Flp Recombinase
[0392] In order to be able to reuse the same deletion strategy as
that used to construct strain JW0715-2 above (Rodriguez et al.,
2016), the selection cassette is deleted using a recombinase.
[0393] Plasmid p707-Flpe (provided in the Quick & Easy E. coli
Gene Deletion Red.RTM./ET.RTM. Recombination Kit by Gene Bridges)
is transformed by electroporation according to the kit protocol.
The cells are selected on LB agar supplemented with 0.2% glucose,
0.0003% tetracycline and added with 0.3% L-arabinose. A
counter-selection of the clones obtained is carried out by
verifying that they are no longer able to grow on the same medium
supplemented with 0.0015% kanamycin.
[0394] The strain obtained is called EQ.EC040: MG1655
.DELTA.sdhA
[0395] b) Deletion of the aceB Gene
[0396] The deletion of the aceB gene (GeneID 948512) is performed
by homologous recombination and the use of the Quick & Easy E.
coli Gene Deletion Red.RTM./ET.RTM. Recombination Kit (Gene
Bridges) according to the supplier's protocol.
[0397] Oligonucleotides designed to amplify an FRT-PKG-gb2-neo-FRT
resistance gene expression cassette and having a 5' sequence
homologous over 50 nucleotides to the adjacent regions of the
deletion locus, i.e. at positions 4215428 to 4215478.and 4217129.to
4217079 on the chromosome thus generating recombination arms of the
cassette on the bacterial genome on either side of the aceB gene
coding sequence.
[0398] The Escherichia coli K-12 strain EQ.EC040 is transformed by
electroporation with plasmid pRedET according to the kit protocol.
The colonies obtained are selected on rich complex medium LB agar
with 0.2% glucose, 0.0003% tetracycline.
[0399] Transformation of the amplicon obtained in the first step in
the presence of RedET recombinase, induced by 0.3% arabinose in
liquid LB for 1 h. To that end, a second transformation of the
deletion cassette is performed by electroporation in cells
expressing RedET and the colonies are selected on LB agar
supplemented with 0.2% glucose, 0.0003% tetracycline and added with
0.3% L-arabinose and 0.0015% kanamycin.
[0400] Plasmid p707-Flpe (provided in the Quick & Easy E. coli
Gene Deletion Red.RTM./ET.RTM. Recombination Kit by Gene Bridges)
is transformed by electroporation according to the kit protocol.
The cells are selected on LB agar supplemented with 0.2% glucose,
0.0003% tetracycline and added with 0.3% L-arabinose. A
counter-selection of the clones obtained is carried out by
verifying that they are no longer able to grow on the same medium
supplemented with 0.0015% kanamycin.
[0401] The strain obtained is called EQ.EC041: MG1655 .DELTA.sdhA
.DELTA.aceB
[0402] c) Change in the icd Gene Promoter
[0403] i. Strategy
[0404] The replacement of the native promoter of the icd gene (Gene
ID: 945702) by a weaker promoter is performed by homologous
recombination and the use of the Quick & Easy E. coli Gene
Deletion Red.RTM./ET.RTM. Recombination Kit (Gene Bridges)
according to the supplier's protocol.
[0405] ii. Introduction of the Weak Promoter P oxb1
[0406] The icd gene promoter is replaced by a cassette coupling the
promoter P.sub.oxb1, characterized as weak, and an antibiotic
resistance gene cassette to allow the selection of the insertion of
the P.sub.oxb1 cassette with an antibiotic resistance gene.
[0407] Oligonucleotides designed to amplify an FRT-PKG-gb2-neo-FRT
resistance gene expression cassette and having a 5' sequence
homologous over 50 nucleotides to the left adjacent region of the
P.sub.icd promoter locus (Genomic target LA) for the sense oligo,
i.e. at positions 1194911 to 1194961 on the genome, and the Spacer
R sequence (Table 23) for the reverse oligo allow amplification of
a fragment allowing assembly with the P.sub.oxb1 fragment.
[0408] Oligonucleotides designed to amplify the P.sub.oxb1 promoter
from plasmid PSF-OXB1 (Sigma # OGS553) and having a 5' sequence
homologous over 50 nucleotides to the right adjacent region of the
P.sub.icd promoter locus (Genomic target RA) for the reverse oligo,
i.e. at positions 1195173 to 1195123 on the genome, and the Spacer
S sequence (Table 25) for the oligo produce amplification of the
P.sub.oxb1 fragment.
[0409] The amplification of a fusion fragment using the
NEBuilder.RTM. HiFi DNA Assembly Master Mix Kit (E2321) allows the
replacement promoter to be combined with an antibiotic selection
cassette.
TABLE-US-00026 TABLE 25 Primer sequences for amplifying the OXB1
gene promoter Sequences of homology Name with vector PSF-OXB1
POXB1-S TCGTTGCGTTACACACAC (SEQ ID NO: 15) POXB1-R
TGTGTCGAGTGGATGGTAG (SEQ ID NO: 16) Spacer S GCATGAATTCG (SEQ ID
NO: 17) Spacer R CGAATTCATGC (SEQ ID NO: 18)
[0410] The Escherichia coli K-12 strain EQ.EC041 is transformed by
electroporation with plasmid pRedET according to the kit protocol.
The colonies obtained are selected on rich complex medium LB agar
with 0.2% glucose, 0.0003% tetracycline.
[0411] Transformation of the amplicon obtained in the first step in
the presence of RedET recombinase, induced by 0.3% arabinose in
liquid LB for 1 hour. To that end, a second transformation of the
deletion cassette is performed by electroporation in cells
expressing RedET and the colonies are selected on LB agar
supplemented with 0.2% glucose, 0.0003% tetracycline and added with
0.3% L-arabinose and 0.0015% kanamycin.
[0412] Plasmid p707-Flpe (provided in the Quick & Easy E. coli
Gene Deletion Red.RTM./ET.RTM. Recombination Kit by Gene Bridges)
is transformed by electroporation according to the kit protocol.
The cells are selected on LB agar supplemented with 0.2% glucose,
0.0003% tetracycline and added with 0.3% L-arabinose. A
counter-selection of the clones obtained is carried out by
verifying that they are no longer able to grow on the same medium
supplemented with 0.0015% kanamycin.
[0413] The strain obtained is called EQ.EC042: MG1655 .DELTA.sdhA
.DELTA.aceB P.sub.icd::P.sub.oxb1
[0414] d) Deletion of the zwf Gene
[0415] The deletion of the zwf gene (GeneID: 946370) is performed
by homologous recombination and the use of the Quick & Easy E.
coli Gene Deletion Red.RTM./ET.RTM. Recombination Kit (Gene
Bridges) according to the supplier's protocol.
[0416] Oligonucleotides designed to amplify an FRT-PKG-gb2-neo-FRT
resistance gene expression cassette and having a 5' sequence
homologous over 50 nucleotides to the adjacent regions of the
deletion locus, i.e. at positions 1934789 to 1934839 and 1936364 to
1936314 on the chromosome thus generating recombination arms of the
cassette on the bacterial genome on either side of the entire
operon.
[0417] The Escherichia coli K-12 strain EQ.EC042 is transformed by
electroporation with plasmid pRedET according to the kit protocol.
The colonies obtained are selected on rich complex medium LB agar
with 0.2% glucose, 0.0003% tetracycline.
[0418] Transformation of the amplicon obtained in the first step in
the presence of RedET recombinase, induced by 0.3% arabinose in
liquid LB for 1 h. To that end, a second transformation of the
deletion cassette is performed by electroporation in cells
expressing RedET and the colonies are selected on LB agar
supplemented with 0.2% glucose, 0.0003% tetracycline and added with
0.3% L-arabinose and 0.0015% kanamycin.
[0419] Plasmid p707-Flpe (provided in the Quick & Easy E. coli
Gene Deletion Red.RTM./ET.RTM. Recombination Kit by Gene Bridges)
is transformed by electroporation according to the kit protocol.
The cells are selected on LB agar supplemented with 0.2% glucose,
0.0003% tetracycline and added with 0.3% L-arabinose. A
counter-selection of the clones obtained is carried out by
verifying that they are no longer able to grow on the same medium
supplemented with 0.0015% kanamycin.
[0420] The strain obtained is called EQ.EC043: MG1655 .DELTA.sdhA
.DELTA.aceB P.sub.icd::P.sub.oxb1 .DELTA.zwf
[0421] e) Deletion of the gapA Gene
[0422] The deletion of the gapA gene is performed by homologous
recombination and the use of the Quick & Easy E. coli Gene
Deletion Red.RTM./ET.RTM. Recombination Kit (Gene Bridges)
according to the supplier's protocol.
[0423] Oligonucleotides designed to amplify an FRT-PKG-gb2-neo-FRT
resistance gene expression cassette and having a 5' sequence
homologous over 50 nucleotides to the adjacent regions of the
deletion locus, i.e. the coding phase of the gene (gapA) (GenBank:
X02662.1) thus generating recombination arms of the cassette on the
bacterial genome.
[0424] The Escherichia coli K-12 strain EQ.EC043 is transformed by
electroporation with plasmid pRedET according to the kit protocol.
The colonies obtained are selected on rich complex medium LB agar
with 0.2% glucose, 0.0003% tetracycline.
[0425] Transformation of the amplicon obtained in the first step in
the presence of RedET recombinase is induced by 0.3% arabinose in
liquid LB for 1 h. To that end, a second electroporation of the
cells expressing RedET by the deletion cassette is performed and
the colonies are selected on LB agar supplemented with 0.2%
glycerol and 0.3% pyruvate, 0.0003% tetracycline and added with
0.3% L-arabinose and 0.0015% kanamycin.
[0426] Plasmid p707-Flpe (provided in the Quick & Easy E. coli
Gene Deletion Red.RTM./ET.RTM. Recombination Kit by Gene Bridges)
is transformed by electroporation according to the kit protocol.
The cells are selected on LB agar supplemented with 0.2% glucose,
0.0003% tetracycline and added with 0.3% L-arabinose. A
counter-selection of the clones obtained is carried out by
verifying that they are no longer able to grow on the same medium
supplemented with 0.0015% kanamycin.
[0427] The strain obtained is called EQ.EC044: MG1655 .DELTA.sdhA
.DELTA.aceB P.sub.icd::P.sub.oxb1 .DELTA.zwf .DELTA.gapA
[0428] f) Constitutive Overexpression of the FPGLOXDH1 and aceA
Genes
[0429] The coding sequences (CDS) of the FPGLOXDH1 (Gene ID:
946058) and aceA (Gene ID: 948517) genes subcloned into a bacterial
expression vector pZE21MCS (EXPRESSYS) as synthetic operons
according to the structure described in Table 24. This vector has a
ColE1 origin of replication and a kanamycin antibiotic resistance
gene.
[0430] Each of these primers is coupled to floating sequences
homologous over 18 nucleotides at the ends of the fragment obtained
by amplifying vector pZE21MCS excluding the multiple cloning site.
The two amplicons are combined according to the protocol of the
In-Fusion.RTM. HD Cloning Kit User Manual--Clontech to form plasmid
pEQEC035 allowing the constitutive overexpression of the FPGLOXDH1
and aceA genes.
[0431] g) Insertion of the Engineering Required for CO.sub.2
Fixation
[0432] For the recombinant expression of the different components
of a functional type I RuBisCO in E. coli, the genes described in
Table 17 (Example 4A]), are cloned in the form of a synthetic
operon.
[0433] The coding sequences (CDS) of the genes described in the
Table 2 are amplified and assembled into blocks according to the
protocol provided with the NEBuilder.RTM. HiFi DNA Assembly Master
Mix Kit (E2321) to obtain three integration blocks described in
Table 26. Each block is then amplified according to the protocol of
the In-Fusion.RTM. HD Cloning Kit User Manual--Clontech to form the
plasmids described below in Table 24.
TABLE-US-00027 TABLE 26 Composition of expression cassettes
Structure of the synthetic operon Block I Block II Block III
Plasmid Vector type CDS A RBS1 CDS B RBS2 CDS C RBS3 CDS D pZA11
pZA11 pEQEC006 pZA11 rbcS D rbcL B rbcX F prk pZE21MCS pZE21MCS
pEQEC035 pZE21MCS FPGLOXDH1 D aceA
[0434] To control the expression level of these genes, ribosome
binding sequences (RBS) presented in Table 19 (Example 4B]), with
variable translation efficiencies (Levin-Karp et al., ACS Synth
Biol. 2013 Jun. 21; 2(6):327-36. doi: 10.1021/sb400002n; Zelcbuch
et al., Nucleic Acids Res. 2013 May; 41(9):e98) are inserted
between the coding phase for each gene. The succession of each
coding phase interspersed by an RBS sequence is constructed by
successive insertions into a pZA11 vector (Expressys) that contains
a PLtetO-1 promoter, a p15A origin of replication and an ampicillin
resistance gene.
[0435] Several strains are produced by electroporating the
different vectors presented according to the plan below
[0436] EQ.EC045.fwdarw.(EQ.EC042+pZA11+pZE21MCS): MG1655
.DELTA.sdhA .DELTA.aceB P.sub.icd::P.sub.oxb1
[0437] EQ.EC046.fwdarw.(EQ.EC045+pEQEC006+pEQEC035): MG1655
.DELTA.sdhA .DELTA.aceB P.sub.icd::P.sub.oxb1 .DELTA.zwf
.DELTA.gapA+(FPGLOXDH1+aceA)+(RuBisCO+PRK)
[0438] After transformation, clones are selected on LB glycerol,
pyruvate medium supplemented with 100 mg/L ampicillin and 30 mg/L
kanamycin. An adaptation and evolution phase of the strains with
PRK and RuBisCO engineering is performed as described in Example
4A].
[0439] h) Production of Succinate and Oxalate
[0440] For the production of succinate and oxalate, cells from 500
mL of LB culture are inoculated into 20 mL of MS medium (40 g/L
glucose, 1 g/L MgSO.sub.4.7H.sub.2O, 20 g/L
(NH.sub.4).sub.2SO.sub.4, 1 g/L KH.sub.2PO.sub.4, 10 mg/L
FeSO.sub.4.7H.sub.2O, 10 mg/L MnSO.sub.4.7H.sub.2O, 2 g/L yeast
extract, 30 g/L CaCO.sub.3, 100 mg/L ampicillin and 30 mg/L
kanamycin at a pressure of 0.1 atmosphere CO.sub.2, at 30.degree.
C. at pH 3.5.
[0441] The succinate concentration is measured by high-performance
liquid chromatography (HPLC), culture samples are centrifuged at
12,000 g for 5 min.
[0442] i. Succinate Determination
[0443] The culture supernatant is filtered through a 0.2 .mu.m
Millipore filter and analyzed on an Agilent HPLC system (series
1100) equipped with a cation-exchange column. (Aminex HPX87-H,
Bio-Rad, Hercules, Calif., USA), a UV absorbance detector (Agilent
Technologies, G1315D) and a refractive index (RI) detector (Agilent
Technologies, HP1047A). The samples are separated on a 5 mM
H.sub.2S0.sub.4 mobile phase at a flow rate of 0.4 mL/min. The
column oven temperature is 65.degree. C.
[0444] Residual glucose is measured with a bioanalyzer (Ysi Inc.)
or by HPLC-refractometry with an Aminex HPX87-H column.
[0445] The carbon yield Y.sub.p/s is calculated in grams of
succinate produced per gram of glucose consumed.
[0446] This yield increases significantly by 6% for the engineering
strain EQ.EC046 compared with the control strain EQ.EC045
(empty).
[0447] ii) Oxalate Determination
[0448] The pellets are washed twice with 10 mM potassium phosphate
buffer (pH 7.5) containing 2 mM EDTA and stored at -20.degree. C.
Samples (1 mL) are transferred into a tube pre-cooled with 0.75 g
of glass beads (425-600 .mu.m) and introduced into a Fast Prep
homogenizer (Thermo Scientific, Erembodegem, Netherlands) and
subjected to 4 bursts of 20 s at speed control 6. The lysates are
centrifuged for 20 min at 4.degree. C. and 36,000 g. Total protein
determinations are performed according to the Lowry method (Lowry
et al., 1951). Oxaloacetate acetyl hydrolase (EC 3.7.1.1.1)
activity is measured using a modification of the direct optical
determination of oxaloacetate (OAA) at 255 nm as described in (Lenz
et al., 1976). The disappearance of the OAA enol tautomer is
checked at 255 nm at 25.degree. C. in a Hitachi Model 100-60
spectrophotometer (Hitachi, Tokyo, Japan), using quartz cuvettes.
The 1 mL reaction mixture contains 100 mM imidazole-HCl (pH 7.5),
0.9 mM MnCl.sub.2.2H.sub.2O, 1 mM OAA, 20 .mu.L cell extract
(controls with different volumes of cell extracts confirm the
linear relationship between enzyme activity and the amount of cell
extract). The reaction is started by adding the cell extract.
[0449] The carbon yield Y.sub.p/s is calculated in grams of
doxalate produced per gram of glucose consumed.
[0450] This efficiency increases significantly by 3% for the
engineering strain EQ.EC046 compared with the control strain
EQ.EC045 (empty).
Example 8: Improvement of Citrate Production in Aspergillus
niger
[0451] a) Strategy
[0452] The inactivation of the pgkA gene (Locus tag An08g02260),
leading to the non-functionality of the glycolysis pathway, and
that of the gsdA gene (Locus tag An02g12140), inhibiting the
oxidative part of the pentose phosphate pathway, are used to
integrate the six genes for the functional expression of the PRK
and RuBisCO enzymes, namely RbcS, RbcL, RbcX, GroES, GroEL and PRK
for CO.sub.2 fixation.
[0453] b) DNA Constructs
[0454] i) Guide RNA Sequences for Targeting the Gene to be
Inactivated
[0455] In each of these two genes, a sequence of 20 nucleotides
punctuated by an NGG motif (CRISPR target sequence underlined) was
determined (Table 27). In both cases, this sequence is specific to
the targeted gene but also unique in the Aspergillus niger genome.
These sequences are used to express a guide RNA (gRNA) which, by
forming a heteroduplex with the homologous region of the
Aspergillus niger genome, directs the action of the CAS9
endonuclease to induce a double-stranded break specifically on the
chosen locus.
TABLE-US-00028 TABLE 27 gRNA target sequence Reference Locus CRISPR
Locus Gene genome tag sequences 1 pgkA A. niger An08g
CAACAAGGCCACTGG CBS 02260) TGGCCAGG 513-88 (SEQ ID NO: 19) 2 gsdA
A. niger An02g CATTTCCGGTCAATA CBS 12140) TGACAAGG 513-88 (SEQ ID
NO: 20)
[0456] Plasmid pFC332 (Addgene #87845) described in Sarkari et al.
(Bioresour Technol. 2017 December; 245(Pt B):1327-1333) contains a
gRNA expression cassette, a cassette allowing the functional
expression of the Cas9 endonuclease and an Hph cassette allowing
the selection of this plasmid. The plasmid also contains the
fragment AMA1_2.8 which allows transient propagation of the
plasmid. Finally, an origin of replication for E. coli is also
present.
[0457] In order to target another gene, the gRNA cassette between
FS A and FS B can be easily exchanged. This plasmid is modified by
amplifying the different parts of this plasmid, in order to
eliminate the antibiotic selection cassette and modify the 20
nucleotides allowing the specificity of gRNA in favor of the
sequences described in Table 27 to form plasmids pEQ0610 to target
pgkA and pEQ0611 to target gsdA.
[0458] Donor Plasmid
[0459] Regions of Homologies with the Genome
[0460] The donor plasmid consists of an In-Fusion.RTM. HD Cloning
Kit User Manual--Clontech assembly between plasmid pUC19 (GenBank:
M77789.2) and the genomic targeting sequences (LA and RA) of
approximately 1500 bp each, homologous to the locus chosen for
integration. The LA and RA sequences are adjacent at 5' and 3'
respectively to the locus sequence targeted by the guide RNA. The
genomic DNA/guide RNA heterodimer is recognized by the Cas9
endonuclease for double-stranded cleavage (locus 1: pgkA; locus 2:
gsdA) (Table 28). The RA and LA fragments are amplified with
primers for the pgkA gene and the gsdA gene (Table 29). The
amplicon sequences are given in the sequence listing (SEQ ID NO: 55
to SEQ ID NO: 58). An extension of 18 nucleotides on all forward
primers of the three fragments is added according to the protocol
of the In-Fusion.RTM. HD Cloning Kit User Manual--Clontech, to
allow a functional assembly of the plasmids (pEQ0600 or pEQ0601)
and the introduction of two restriction sites for type II
restriction endonucleases (restriction enzymes I-CeuI and I-Sce)I
which have large asymmetric recognition sites (12 to 40 base
pairs). These are recognition sequences of 18 base pairs, so rare.
The fact that the cleavage is asymmetric at the reconnaissance site
allows the release of a fragment lacking sequences from bacterial
vector pUC19. These two enzymes allow the integration block to be
extracted by restriction after amplification by cloning in E.
coli.
TABLE-US-00029 TABLE 28 Amplification of regions of homologies for
the pgkA gene Primer Amplicon Alias position Primer sequence 5'
pgkA_ LA1 Forward GGATCGCAGATACGG A. niger TCGC (SEQ ID NO: 21)
Reverse CCTCGGTGAAGACAA CGCTG (SEQ ID NO: 22) 3' pgkA_ RA1 Forward
CTCCTTGAGAACCTG A. niger CGTTTCC (SEQ ID NO: 23) Reverse
CTGAAGTACGTTTTC CCAAGCC (SEQ ID NO: 24)
TABLE-US-00030 TABLE 29 Amplification of regions of homologies for
the gsdA gene Primer Amplicon Alias position Primer sequence 5'
gsdA_ LA2 Forward CGTTATCACAAAGAA A. niger GCCAGGTCC (SEQ ID NO:
25) Reverse GCTGCTCTTCGATTT CCTTGGT (SEQ ID NO: 26) 3' gsdA_ RA2
Forward TCATCAACCTCAACA A. niger AGCACCTC (SEQ ID NO: 27) Reverse
GTGAAGACAGCGGCG GTCC (SEQ ID NO: 28)
[0461] Engineering Expression Cassettes
[0462] The promoters and terminators are identified on the basis of
GenBank data. The selected promoters are determined from the +1
transcription point and go up 1.4 kb upstream in order to cover
both the "core" sequences (TATA box) and the trans-activating
sequences allowing the optimal functionality of the promoter
concerned.
[0463] For the terminators, the cut-off is made 500 bp after the
stop codon of the gene.
[0464] The structure of each integration block of four expression
cassettes is defined as follows: the first level consists of simple
elements, namely promoters, coding sequences (CDS) and terminators.
The promoter (Table 30) and terminator (Table 31) elements, whose
sequences are provided in the sequence listing (SEQ ID NO: 59 to
62), are amplified and assembled with the engineering CDS according
to Table 32. The CDS, whose sequences are provided in the sequence
listing (SEQ ID NO: 63 to 66), are amplified according to the
protocol provided with the NEBuilder.RTM. HiFi DNA Assembly Master
Mix Kit (E2321) to obtain the functional expression cassettes
compiled in the table. Each integration block of four genes is
organized to include four different pairs (promoter/terminator) in
order to limit trans interference. Each integration block of six
genes is organized to include six different pairs
(promoter/terminator) in order to limit transcriptional
interference
[0465] Donor Fragment for Insertion into the Target Locus of the
Genome
[0466] The different multiple expression cassettes (RbcS, RbcL and
RbcX) or (GroES, GroEL and PRK) are amplified and assembled around
an antibiotic selection cassette (Table), according to the protocol
of the In-Fusion.RTM. HD Cloning Kit User Manual--Clontech, to form
donor plasmids (pEQ0602 or pEQ0603).
TABLE-US-00031 TABLE 30 Native location of Aspergillus niger
promoters used in genomic combinatorics to insert the six genes of
the CO.sub.2 fixation engineering into the Aspergillus niger
genome. Pro- Gene Reverse Forward moters Organism ID primer primer
PmbfA A. niger An02g TTTGAAGATGGA GCCATGAAATC CBS 12390 TGAGAAGTCGG
CAATCATTTCC 513-88 (SEQ ID (SEQ ID NO: 33) NO: 29) PcoxA A. niger
An07g TGTCCTGGTGGG GACGGCATTTG CBS 07390 TGGGTTG AGCAACATC 513-88
(SEQ ID (SEQ ID NO: 34) NO: 30) PsrpB A. niger An16g CTCGAACGAGAA
TTGGCAGGGTC CBS 08910 TGGGAACC ACGTAGCC 513-88 (SEQ ID (SEQ ID NO:
35) NO: 31) PtvdA A. niger An04g GGCGGAATGAGA TTAGTCCATTC CBS 01530
TGCGACAG AGCAAGCTGCC 513-88 (SEQ ID (SEQ ID NO: 36) NO: 32)
TABLE-US-00032 TABLE 31 Native location of Aspergillus Niger
terminators used in genomic combinatorics to insert the six genes
of the CO.sub.2 fixation engineering into the Aspergillus niger
genome. Ter- Gene Forward Reverse minators Organism ID primer
primer TtrpC A. AN0648 TGATTTAATA GGGTAAACG nidulans GCTCCATGTC
ACTCATAGG FGSC A4 AACAAG AGA (SEQ ID (SEQ ID NO: 37) NO: 41) TniaD
A. AN1006 ACGGGTTCGC GGGATATTT nidulans ATAGGTTTGG GACACGATT FGSC
A4 (SEQ ID CTGAGG NO: 38) (SEQ ID NO: 42) TgiaA A. niger An03g
CGACCGCGAC CCGGAGATC CBS 513- 06550 GGTGACTGAC CTGATCATC 88 (SEQ ID
CG NO: 39) (SEQ ID NO: 43) TgpdA A. niger An16g GAATCAGGAC
CGTGGTCTA CBS 513- 01830 GGCAAACTGA GCTGCCCTC 88 AT C (SEQ ID (SEQ
ID NO: 40) NO: 44)
TABLE-US-00033 TABLE 32 Assembly of expression cassettes Codon
Expression optimi- Termi- cassette Gene GenBank zation Promoter
nator CAS 1 RbcL BAD78320.1 Yes PmbfA.sub.p trpct CAS 2 RbcS
BAD78319.1 Yes PcoxA.sub.p TniaD CAS 3 RbcX BAD80711.1 Yes
PsrpB.sub.p glaAt CAS 4 Hph pUG75(P30671) No picdA.sub.p TgpdA CAS
5 GroES U00096 No PmbfA.sub.p trpct CAS 6 GroEL AP009048 No
PcoxA.sub.p TniaD CAS 7 PRK BAD78757.1 Yes PsrpB.sub.p glaAt CAS 8
Ble pUG66(P30116) No picdA.sub.p TgpdA
TABLE-US-00034 TABLE 33 Plasmid assembly Genomic Genomic Selection
Plasmid sequence Promoter Gene Terminator sequence ori marker
pEQ0600 LA1 RA1 coli Ampicillin pEQ0601 LA2 RA2 coli Ampicillin
pEQ0602 LA2 PmbfA.sub.p RbcL trpct RA2 coli Ampicillin and
PcoxA.sub.p RbcS TniaD coli hydromycin B PsrpB.sub.p RbcX glaAt
coli picdA.sub.p Hph TgpdA coli pEQ0603 LA1 PmbfA.sub.p GroES Trpct
RA1 coli Ampicillin and PcoxA.sub.p GroEL TniaD coli bleomycin
PsrpBp PRK glaAt coli picdAp Blue TgpdA coli
[0467] c) Transformation of Aspergillus niger
[0468] The transformation of DNA in Aspergillus niger is
constrained by the presence of the fungal cell wall, and is
extremely ineffective compared with yeast or Escherichia coli.
Nevertheless, the transformation of protoplasts prepared from
fungal hyphae or conidiospores to germination by treatment with
cell wall degrading enzymes such as the cocktail consisting of
Lysing Enzyme.RTM. from Trichoderma harzianum, chitinase from
Streptomyces griseus and .beta.-glucuronidase from Helix pomatia
(de Bekker et al., J Microbiol Methods. 2009 March; 76(3):305-6)
allows transformants to be produced.
[0469] The A. niger strain CBS 513-88 is grown at 30.degree. C. in
a 1 L Erlenmeyer flask with 250 mL of transformation medium
(Kusters-van Someren et al., Curr Genet. 1991 September;
20(4):293-9). After growth for 16 h at 250 rpm, the mycelium is
collected by filtration on Miracloth (Calbiochem) and washed with
deionized water. Protoplasts are prepared in the presence of 5 g/L
lysis enzymes from Trichoderma harzianum (Sigma Saint Louis, Mo.,
USA), 0.075 Uml-1 chitinase from Streptomyces griseus (Sigma) and
460 Uml-1 glucuronidase from Helix pomatia (Sigma) in KMC (0.7 M
KCl, 50 mM CaCl.sub.2, 20 mM Mes/NaOH, pH 5.8) for 2 hours at
37.degree. C. and 120 rpm. Protoplasting is monitored every 30
minutes with a microscope. The protoplasts are filtered through a
Miracloth filter and collected by centrifugation at 2000.times.g
and 4.degree. C. for 10 minutes. The protoplasts are washed with
cold STC (1.2 M sorbitol, 10 mM Tris/HCl, 50 mM CaCl.sub.2, pH 7.5)
and then resuspended in 100 pi of STC and used directly for the
transformation.
[0470] In order to integrate a metabolic pathway into the A. niger
genome, co-transformation of a plasmid and a linear fragment is
required. Plasmid pEQ0610 is co-transformed with a donor fragment
to integrate part of the engineering into the genome while
inactivating the pgkA gene. Similarly, plasmid pEQ0611 is
co-transformed with a donor fragment to integrate the other part of
the engineering into the genome while inactivating the gsdA gene.
These sequences serve both as matrices for homologous recombination
and as selection markers: during integration with functional
expression of the antibiotic resistance genes Hph or Ble. The
strains are directly selected on minimal medium plates with an
addition of hygromycin B or bleomycin allowing direct selection on
the integration event. Due to the presence of the origin of
replication AMA1_2.8, plasmid pCAS_pyrG2 is easily lost causing
only transient expression of the Cas9 protein, thus reducing the
risk of non-targeted adverse effects.
[0471] Linear cassettes (10 .mu.g) and plasmid (5 .mu.g) are mixed
with 100 .mu.L of STC solution containing at least 10.sup.7
protoplasts and 330 .mu.L of freshly prepared polyethylene glycol
(PEG) solution (25% PEG 6000, 50 mM CaCl.sub.2, 10 mM Tris/HCl, pH
7.5) and kept on ice for 20 minutes. After mixing with an
additional 2 mL PEG solution and incubating at room temperature for
10 minutes, the protoplast mixture is diluted with 4 mL of STC.
[0472] The selection of transformants is carried out on MM plates
with 150 .mu.g/mL hygromycin B added or MM plates with 50 .mu.g/mL
bleomycin added. All transformants are purified by isolating single
colonies from the selection medium at least twice. The insertion of
the fragments is verified by sequencing the target locus with the
appropriate control primers. Genomic DNA from fungal cells is
isolated with a modified protocol, using the Wizard.RTM. Genomic
DNA Purification Kit (Promega, Wisconsin, USA). The mycelium is
cultured overnight in CM (30.degree. C., 150 rpm) in 290 pi of 50
mM EDTA solution and 10 pi of lyticase (10 mg/mL) to remove the
cell wall. After 90 minutes of incubation at 37.degree. C., the
suspension is centrifuged and the supernatant is discarded. The
mycelium pellet is resuspended in 300 .mu.L of nuclei lysis
solution and 100 .mu.L of protein precipitation solution. The
samples are incubated on ice for 5 minutes and centrifuged. The DNA
is precipitated with isopropanol and washed with 70% ethanol. The
DNA pellet is rehydrated with a DNA rehydration solution containing
RNase (100 .mu.g/mL). The successful transformation and integration
of the expression cassettes was verified by PCR.
TABLE-US-00035 TABLE 34 Strains used for the yield study Strains
Genome Genetic modification EQ1500 A. niger CBS 513-88 EQ1501 A.
niger gsdA :: PmbfA.sub.p-RbcL-trpc; PcoxA.sub.p-RbcS-TniaD; CBS
picdA.sub.p-Hph-TgpdA; PsrpB.sub.p-RbcX-glaAt 513-88 EQ1502 A.
niger gsdA :: PmbfA.sub.p-RbcL-trpc; PcoxA.sub.p-RbcS-TniaD; CBS
picdA.sub.p-Hph-TgpdA; PsrpB.sub.p-RbcX-glaAt 513-88 pgkA ::
PmbfA.sub.p-GrES-trpc; PcoxA.sub.p-GroEL-TniaD;
picdA.sub.p-Ble-TgpdA; PsrpB.sub.p-PRK-glaAt
[0473] Conidia (10.sup.8/L) from strains EQ1500 and EQ1502 are
inoculated and cultured at 30.degree. C. on a rotary shaker (180
rpm) in shaker flasks containing Vogel medium without MnSO.sub.4
with a total glucose content of 15% and a total nitrogen content of
0.2% and 10% CO.sub.2. The determination of glucose and organic
acids was performed as described above (Blumhoff et al., 2013;
Steiger et al., 2016) on an HPLC (Shimadzu, Kyoto; Japan) equipped
with an Aminex HPX-87 H column (300.times.7.8 mm, Bio-Rad,
Hercules, Calif.). A refractive index detector (RID-10 A, Shimadzu)
is used for the detection of glucose and citric acid, while a PDA
detector (SPD-M20A, Shimadzu) at 300 nm is used to detect
cis-aconitic and trans-aconitic acid. The column is used at
60.degree. C. at a flow rate of 0.6 mL/min and with a 0.004 M
H.sub.2SO.sub.4 aqueous solution as mobile phase. The culture was
carried out in three biological replicates.
[0474] d) Analytical Method
[0475] For the quantification of extracellular metabolites, a
culture sample is centrifuged at 14,000.times.g for 5 min. The
supernatant is filtered through a filter with a 0.45 pm pore size.
The filtrate is maintained at -20.degree. C. until analysis. The
concentration of citrate and of oxalate is detected and quantified
with ultraviolet light at 210 nm using an Amethyst C18-H column
(250.times.4.6 mm, Sepax Technologies, Newark, Del., USA). Elution
is carried out at 30.degree. C. with 0.03% H.sub.3P0.sub.4 at a
flow rate of 0.8 mL/min. Reducing sugar is detected with the
3,5-dinitrosalicylic acid method. Biomass determination: 5 mL of
sample is filtered through Miracloth (Calbiochem, San Diego,
Calif., USA) to collect hyphae and washed with distilled water. The
hyphae are heated to 105.degree. C. in a "Miracloth". For the
calculation of the dry cell weight (DCW), the weight of Miracloth
is measured beforehand and subtracted from the total weight to give
the net weight, then the net weight per unit volume is calculated
as DCW.
[0476] After complete analysis, the comparison of citric acid
production yield as a function of glucose consumption is 18% higher
in the engineered strain EQ1502 than in the wild-type strain
EQ1500.
Example 9: Improvement of Itaconate Production in Aspergillus
terreus
[0477] a) Strategy
[0478] Inactivation of the pgkA gene (Locus tag (ATEG_00224),
leading to the non-functionality of the glycolysis pathway, and
that of the gsdA gene (Locus tag ATEG_01623), inhibiting the
oxidative part of the phosphate pentose pathway, are used to
integrate the six genes allowing the functional expression of the
PRK and RuBisCO enzymes, namely rbcS, rbcL, rbcX, groES, groEL and
prk allowing CO.sub.2 fixation.
[0479] b) DNA Constructs
[0480] i) RNA Guide Sequences to Target the Gene to be
Inactivated
[0481] In each of these two genes, a sequence of 20 nucleotides
punctuated by an NGG motif (CRISPR target sequence underlined) was
determined (Table 35). In both cases, this sequence is specific to
the targeted gene but also unique in the Aspergillus terreus
genome. These sequences are used to express a guide RNA (gRNA)
which, by forming a heteroduplex with the homologous region of the
Aspergillus terreus genome, directs the action of the CAS9
endonuclesae to induce a double-stranded break specifically on the
selected locus. For pgkA, the sequence identified in the second
intron, the first 20 nucleotides have a unique pattern in the
genome, even allowing two mismatches. For gsdA, the sequence
identified in the fourth intron, the first 20 nucleotides have a
unique pattern in the genome, even allowing two mismatches.
TABLE-US-00036 TABLE 35 Guide RNA target sequence Reference Locus
Locus Gene genome tag CRISPR sequences 3 pgkA A. (ATEG_
CTGCGTCGGCAA terreus 00224) GGAAGTTGAGG NIH262 (SEQ ID NO: 45) 4
gsdA A. (ATEG_ CATCAGCGGCCA terreus 01623) ATATGACAAGG NIH2624 (SEQ
ID NO: 46)
[0482] Plasmid pFC332 (Addgene #87845) described in Sakari et al.
(Bioresour technol. 2017; 245(Pt B):1327-1333) contains a gRNA
expression cassette, a cassette for the functional expression of
the Cas9 endonuclease and an Hph cassette for the selection of this
plasmid. The plasmid also contains the fragment AMA1_2.8 which
allows transient propagation of the plasmid. Finally, an origin of
replication for E. coli is also present.
[0483] In order to target another gene, the gRNA cassette between
FS A and FS B can be easily exchanged. Thus, this plasmid is
modified by amplifying the different parts of this plasmid in order
to eliminate the antibiotic selection cassette and to modify the 20
nucleotides allowing the specificity of gRNA in favor of the
sequences described in Table 35 to form plasmids pEQ0615 to target
pgkA and pEQ0616 to target gsdA in the Aspergillus terreus
genome.
[0484] ii) Donor Plasmid
[0485] Regions of Homology with the Genome
[0486] The donor plasmid consists of an In-Fusion.RTM. HD Cloning
Kit User Manual--Clontech assembly between plasmid pUC19 (GenBank:
M77789.2) and genomic targeting sequences (LA and RA) of
approximately 1500 bp each homologous to the locus chosen for
integration. The LA and RA sequences are adjacent at 5' and 3'
respectively to the locus sequence targeted by the guide RNA. The
genomic DNA/guide RNA heterodimer is recognized by the Cas9
endonuclease for double-stranded cleavage (locus 1: pgkA; locus 2:
gsdA) (Table 35). The RA and LA fragments are amplified with the
primers described in Table 36, for the pgkA gene, and Table 37, for
the gsdA gene. The amplicon sequences are in the sequence listing
(SEQ ID NO: 67 to 70).
[0487] An extension of 18 nucleotides on all forward primers of the
three fragments is added according to the protocol of the
In-Fusion.RTM. HD Cloning Kit User Manual--Clontech to allow a
functional assembly of the plasmids (pEQ0604 or pEQ0605) (33) and
the introduction of two restriction sites for type II restriction
endonucleases (restriction enzymes I-CeuI and I-SceI) which have
large asymmetric recognition sites (12 to 40 base pairs). These are
recognition sequences of 18 base pairs, therefore rare and not
present in the described assembly. The fact that the cleavage is
asymmetric at the reconnaissance site allows a fragment devoid of
sequences to be released from the bacterial vector pUC19. These two
enzymes allow the integration block to be extracted by restriction
after amplification by cloning in E. coli.
TABLE-US-00037 TABLE 36 Amplification of regions of homologies for
the pgkA gene Primer Amplicon position Primer sequence 5' pgkA_
Forward CTTGGGGAATTGG Aterreus GACACG (SEQ ID NO: 47) Reverse
TCTTGCCGATGAG CTTCTCC (SEQ ID NO: 48) 3' pgkA_ Forward
CAGATCATCCTCC Aterreus TGGAGAACC (SEQ ID NO: 49) Reverse
ACGGCACGAATGT TCACCTG (SEQ ID NO: 50)
TABLE-US-00038 TABLE 37 Amplification of regions of homologies for
the gsdA gene Primer Amplicon position Primer sequence 5' gsdA_
Forward ATTGGAAGCTGGCTCT Attereus ATCTCACC (SEQ ID NO: 51) Reverse
GCTGTTCTTCGATTTC CTTGGTG (SEQ ID NO: 52) 3' gsdA_ Forward
TCAACCTCACCAAGCA Aterreus CCTCG (SEQ ID NO: 53) Reverse
CAAACAGCCCGTCGCA ACTG (SEQ ID NO: 54)
[0488] Engineering Expression Cassettes
[0489] Promoters and terminators are identified on the basis of
GenBank data. The selected promoters are determined from the +1
transcription point and go up 1.4 kb upstream in order to cover
both the "core" sequences (TATA box) and the trans-activating
sequences allowing the optimal functionality of the promoter
concerned.
[0490] For the terminators, the cut-off is made 500 bp after the
stop codon of the gene.
[0491] The structure of each integration block of four expression
cassettes is defined as follows: the first level consists of simple
elements, namely promoters, coding sequences (CDS) and terminators.
The promoter (Table 30) and terminator (Table 31) elements are
amplified and assembled with the engineering CDS according to Table
32. The CDS are amplified according to the protocol provided with
the NEBuilder.RTM. HiFi DNA Assembly Master Mix Kit (E2321) in
order to obtain the functional expression cassettes compiled in the
table. Each integration block of four genes is organized to include
four different terminator promoter pairs in order to limit trans
interference Each integration block of six genes is organized to
include six different terminator promoter pairs in order to limit
transcriptional interference.
[0492] Donor Fragment for Insertion into the Target Locus of the
Genome
[0493] The different multiple expression cassettes (RbcS, RbcL and
RbcX or GroES, GroEL and PRK are amplified and assembled around an
antibiotic selection cassette (Table 38), according to the protocol
of the In-Fusion.RTM. HD Cloning Kit User Manual--Clontech, to form
donor plasmids (pEQ0606 or pEQ0607).
TABLE-US-00039 TABLE 38 Plasmid assembly Genomic Genomic Selection
Plasmids sequence Promoter Gene Terminator sequence ori marker
pEQ0604 LA4 RA4 coli Ampicillin pEQ0605 LA3 RA3 coli Ampicillin
pEQ0606 LA4 PmbfA.sub.p rbcL trpct RA4 coli Ampicillin and
PcoxA.sub.p rbcS TniaD coli hydromycin B PsrpB.sub.p rbcX glaAt
coli picdA.sub.p Hph TgpdA coli pEQ0607 LA3 PmbfA.sub.p groES trpct
RA3 coli Ampicillin and PcoxA.sub.p groEL TniaD coli bleomycin
PsrpB.sub.p prk glaAt coli picdA.sub.p Ble TgpdA coli
[0494] c) Transformation of Aspergillus terreus
[0495] The transformation of Aspergillus terreus DNA is carried out
in accordance with the strategy applied for Aspergillus niger
(Example 8) using A. terreus strain NIH262.
TABLE-US-00040 TABLE 39 Strains used for the yield study Strains
Genome Genetic modification EQ1600 A. terreus NIH262 EQ1601 A.
terreus gsdA :: PmbfA.sub.p-RbcL-trpc; PcoxA.sub.p-RbcS-TniaD;
NIH262 picdA.sub.p-Hph-TgpdA; PsrpB.sub.p-RbcX-glaAt EQ1602 A.
terreus gsdA :: PmbfA.sub.p-RbcL-trpc; PcoxA.sub.p-RbcS-TniaD;
NIH262 picdA.sub.p-Hph-TgpdA; PsrpB.sub.p-RbcX-glaAt pgkA ::
PmbfA.sub.p-GrES-trpc; PcoxA.sub.p-GroEL-TniaD;
picdA.sub.p-Ble-TgpdA; PsrpB.sub.p-PRK-glaAt
[0496] Culture of A. terreus strains EQ1600 and EQ1602 on 3%
glucose.
[0497] The optimized media composition described by Hevekerl et al.
(Appl Microbiol Biotechnol. 2014; 98:6983-6989) is used. It
contains 0.8 g KH.sub.2P0.sub.4, 3 g NH.sub.4N0.sub.3, 1 g
MgSO.sub.4.7H20, 5 g CaCl.sub.2.2 H.sub.20, 1.67 mg
FeCl.sub.3.6H.sub.2O, 8 mg ZnSO.sub.4.7H.sub.2O and 15 mg
CuSO.sub.4.7H2O per liter. To mimic the typical sugar concentration
obtained from wheat straw hydrolysate (150 g/L) pretreated with
dilute acid (0.75% v/v, 160.degree. C., 10 min) and enzymatically
saccharified (pH 5.0, 45.degree. C., 72 h), an adequate amount of
glucose up to 30 g/L is used. Sugars and all other components are
added from sterile stock solutions. The pH of the medium without
CaCl.sub.2 is adjusted to 3.1 with 0.5 M H.sub.2SO.sub.4 before
inoculating the spore preparation for strains EQ1600 and EQ1602.
The culture is carried out under shaking with 25 mL of medium in
125 mL Erlenmeyer flasks at 33.degree. C. in a rotary shaker at 200
rpm for 7-10 days in an environment of 10% CO.sub.2. The pH is not
checked during fermentation. Shaking of the flasks is maintained
during sampling for time studies to ensure a continuous supply of
oxygen. All experiments are carried out in triplicate. All media
components are obtained from Sigma Chemical, St. Louis, Mo. For
these experiments, each sugar was dissolved in deionized water and
passed through a column (440.times.45 mm) of Dowex 50-X8 (100/200
mesh) cation-exchange resin (Bio-Rad Laboratories, Hercules,
Calif.) to remove manganese, if necessary.
[0498] d) Analytical Procedures
[0499] The concentration of the cell mass is determined from the
dry cell weight. The cell mass present in the fermentation broth is
collected by centrifugation at 10,000 g for 10 minutes and
carefully rinsed three times with deionized water. The rinsed cell
mass was completely dried at 80.degree. C. until a constant weight
was obtained. The fermentation broth after centrifugation (10,000
g, 10 min) is stored at -20.degree. C. before analysis of glucose,
itaconic acid and by-products (succinic acid, .alpha.-ketoglutaric
acid, malic acid, cis-aconitic acid, and trans-aconitic acid) using
high-performance liquid chromatography (HPLC). A Shimadzu
Prominence HPLC system (Shimadzu America, Inc., Columbia, Md.) is
used. Two columns (Aminex HPX-87P column, 300.times.7.8 mm with ash
removal cartridge and Carbo-P protection cartridge, and one Aminex
HPX 87H column, 300.times.7.8 mm with Microguard Cation H cartridge
(Bio-Rad)) are used for the analysis of sugars and organic acids,
respectively. The Aminex HPX 87P column is maintained at 85.degree.
C. and glucose is eluted with Milli-Q acidified deionized water
(Millipore, Bedford, Mass.) at a flow rate of 0.6 mL/min.
[0500] The Aminex HPX 87H column is maintained at 65.degree. C. and
sugars and organic acids are eluted with 5 mM H.sub.2SO.sub.4
prepared using Milli-Q deionized filtered water at a rate of 0.5
mL/min. Detection is carried out using a refractive index detector
for sugars and a 210 nm UV detector for organic acids. Propionic
acid (1%, weight/volume) is used as internal standard to estimate
the liquid lost during aerobic fermentation for 7-10 days at
33.degree. C. under 10% CO.sub.2. All HPLC standards, including
organic acids, are purchased from Sigma. The manganese
concentration (ppb level) is determined using an Optima 7000DV
(Perkin-Elmer, Waltham, Mass.) inductively coupled plasma optical
emission spectrometer (ICP-OES) by the procedure described by
Bakota et al. (Eur J Lipid Sci Technol. 2015; 117:1452-1462.
[0501] Based on the results of the production of itaconic acid from
glucose, a mass yield increment of itaconic acid from glucose of
15% is observed for the engineered strain EQ1602 compared with the
reference strain EQ1600.
Sequence CWU 1
1
71176DNAartificial sequenceoligonucleotide CB101 (forward)
1acagatcatc aaggaagtaa ttatctactt tttacaacaa atataaaaca atgggtaagg
60aaaagactca cgtttc 76281DNAartificial sequenceoligonucleotide
CB102 (reverse) 2gggaaagaga aaagaaaaaa attgatctat cgatttcaat
tcaattcaat ttagaaaaac 60tcatcgagca tcaaatgaaa c 81365DNAartificial
sequencesynthetic oligonucleotide 3aagagtaaat ccaatagaat agaaaaccac
ataaggcaag atgggtaaaa agcctgaact 60caccg 65463DNAartificial
sequencesynthetic oligonucleotide 4atttcagtga cttagccgat aaatgaatgt
gcttgcattt ttttattcct ttgccctcgg 60acg 63576DNAartificial
sequencesynthetic oligonucleotide 5acagatcatc aaggaagtaa ttatctactt
tttacaacaa atataaaaca atgggtaagg 60aaaagactca cgtttc
76681DNAartificial sequencesynthetic oligonucleotide 6gggaaagaga
aaagaaaaaa attgatctat cgatttcaat tcaattcaat ttagaaaaac 60tcatcgagca
tcaaatgaaa c 81775DNAartificial sequencesynthetic oligonucleotide
7tctccctatc ctcattcttc tcccttttcc tccataattg taagagaaaa atgggtacca
60ctcttgacga cacgg 75878DNAartificial sequencesynthetic
Oligonucleotide 8aatttgaaca cacttaagtt gcagaacaaa aaaaagggga
attgttttca ttaggggcag 60ggcatgctca tgtagagc 78912DNAartificial
sequenceribosome binding sequence 9aggaggtttg ga
121022DNAartificial sequenceribosome binding sequence 10aacaaaatga
ggaggtactg ag 221116DNAartificial sequenceribosome binding sequence
11aagttaagag gcaaga 161214DNAartificial sequenceribosome binding
sequence 12ttcgcagggg gaag 141318DNAartificial sequenceribosome
binding sequence 13taagcaggac cggcggcg 181412DNAartificial
sequenceribosome binding sequence 14caccatacac tg
121518DNAartificial sequenceoligonucleotide POXB1-S 15tcgttgcgtt
acacacac 181619DNAartificial sequenceoligonucleotide POXB1-R
16tgtgtcgagt ggatggtag 191711DNAartificial sequenceoligonucleotide
Spacer S 17gcatgaattc g 111811DNAartificial sequenceoligonucleotide
Spacer R 18cgaattcatg c 111923DNAartificial sequencegRNA target
sequence for CRISPR pgkA 19caacaaggcc actggtggcc agg
232023DNAartificial sequencegRNA target sequence for CRISPR gsdA
20catttccggt caatatgaca agg 232119DNAartificial sequenceprimer LA1
forward 21ggatcgcaga tacggtcgc 192220DNAartificial sequenceprimer
LA1 reverse 22cctcggtgaa gacaacgctg 202322DNAartificial
sequenceprimer RA1 forward 23ctccttgaga acctgcgttt cc
222422DNAartificial sequenceprimer RA1 reverse 24ctgaagtacg
ttttcccaag cc 222524DNAartificial sequenceprimer LA2 forward
25cgttatcaca aagaagccag gtcc 242622DNAartificial sequenceprimer LA2
reverse 26gctgctcttc gatttccttg gt 222723DNAartificial
sequenceprimer RA2 forward 27tcatcaacct caacaagcac ctc
232819DNAartificial sequenceprimer RA2 reverse 28gtgaagacag
cggcggtcc 192922DNAartificial sequenceprimer 29gccatgaaat
ccaatcattt cc 223020DNAartificial sequenceprimer 30gacggcattt
gagcaacatc 203122DNAartificial sequenceprimer 31ttagtccatt
cagcaagctg cc 223222DNAartificial sequenceprimer 32ttagtccatt
cagcaagctg cc 223323DNAartificial sequenceprimer 33tttgaagatg
gatgagaagt cgg 233419DNAartificial sequenceprimer 34tgtcctggtg
ggtgggttg 193520DNAartificial sequenceprimer 35ctcgaacgag
aatgggaacc 203620DNAartificial sequenceprimer 36ggcggaatga
gatgcgacag 203726DNAartificial sequenceprimer 37tgatttaata
gctccatgtc aacaag 263820DNAartificial sequenceprimer 38acgggttcgc
ataggtttgg 203920DNAartificial sequenceprimer 39cgaccgcgac
ggtgactgac 204022DNAartificial sequenceprimer 40gaatcaggac
ggcaaactga at 224125DNAartificial sequenceprimer 41gggtaaacga
ctcataggag agttg 254224DNAartificial sequenceprimer 42gggatatttg
acacgattct gagg 244320DNAartificial sequenceprimer 43ccggagatcc
tgatcatccg 204419DNAartificial sequenceprimer 44cgtggtctag
ctgccctcc 194523DNAartificial sequencesequence for CRISPR pgkA
45ctgcgtcggc aaggaagttg agg 234623DNAartificial sequencesequence
for CRISPR gsdA 46catcagcggc caatatgaca agg 234719DNAartificial
sequenceprimer 47cttggggaat tgggacacg 194820DNAartificial
sequenceprimer 48tcttgccgat gagcttctcc 204922DNAartificial
sequenceprimer 49cagatcatcc tcctggagaa cc 225020DNAartificial
sequenceprimer 50acggcacgaa tgttcacctg 205124DNAartificial
sequenceprimer 51attggaagct ggctctatct cacc 245223DNAartificial
sequenceprimer 52gctgttcttc gatttccttg gtg 235321DNAartificial
sequenceprimer 53tcaacctcac caagcacctc g 215420DNAartificial
sequenceprimer 54caaacagccc gtcgcaactg 20551881DNAartificial
sequenceamplicon 5'pgkA A. niger 55ggatcgcaga tacggtcgca cagttaatca
cggctttcaa ggctcgtgga ggacgcaggc 60cctctgacag taacgatctt atttcaattg
agatccatga cctcgataaa gagaagccgc 120ctgctcttgg agagctggga
catgctagac atatgccgcc gcccttcgac ttcgagcgcc 180tgactcgctt
tatgtcgtac ggtttcttca tggccccggt tcagttccat tggttcggtt
240tcttgtccag ggcgttcccc cttaccaaga ggaacccgtc gattcccgcg
ctgaagagag 300tgtgcgtgga tcagctgatg ttcgctcctt ttggtatgaa
ctgtctccga aggaagaaga 360aagctctttt ctcttagcta atattattac
caggtctggc gtgcttcttc tccttcatga 420cggttgcaga gggaggagga
aggagagcct tgacgcgcaa gttccaggac gtctatctgc 480caaccctcaa
ggccaacttt gtcctttggc ccgctgttca gattctgaac ttccgtgtcg
540tacctatcca gttccagatt gtgagtacta ttgtgataaa actcttgtgc
actgttatac 600tgatatttct tttttcttcc agcccttcgt gtcttccgtc
ggaatcgcct ggactgcgta 660tctgtcgctg accaactctt cggaggagga
gtaatggtag tagcgggctc atattttggc 720tcccacaagg ttcccaatcg
tttcttctgt caattgtctg tcattcttcc ttcccctgcg 780tcgtttcgtg
cttactgggc gctgtaaatg aacttcgggg gttctgttat tcttcctctc
840atgggtggtg tataggtctt cgtccagcag tgtgggtaca ccggagtcaa
ttgcattgat 900cgataaacca tgtcgacaaa atgaattata caccattgtt
tttcgggttt gaaccaggca 960cgaatgatgg aatgtctcct gtaggcgggg
ttgtccccac gagcgagccg gcatccatag 1020acgagaaata tcggaacgat
tgcttgatag atccaccccc ggacgcagca gaagctccca 1080tcgcagcaat
gatccgaggc taaggggctc cgaacggggc ataacaggca taatgttcac
1140ccctgaggcc ccggaccctt ccgtcatcga ttcgcgggcg ctgacatcag
tcccgcatca 1200gcccgaggcg cccgcgattt caacttctct caccggctgc
cccaccacca gcccatacca 1260cttttacccc gccgccgaac cgaatgaagt
cgtagcttcc agtgaccaga ctcgctcacc 1320gcggacctat taagtaggca
tttttcccaa tctcctcatc ccccgtggtg ctactaatac 1380tacgtctctc
cccctcccaa tttctccttt ctctcttttt ttgtcacccc acttccctat
1440cttcccctca catcctctaa ccccgtccga ctgtcgtaga accgtcgttc
atcatgtctc 1500ttaccaacaa gctcgctatc accgatgtcg acctcaagga
caagcgtgtc ctgatccggg 1560tatgttgttg ccccggaaac ccccaccttt
tcatcagtca ccgtcgtggg gtttaagatg 1620agccttcaat gctaactagt
ctgctcactg gacaggtcga cttcaacgtc cccctcaatg 1680acaagaagga
gatcaccaac aaccagcgta tcgtcggtgc tctgcccacc atcaagtacg
1740ctatcgagaa tggtgccaag gccgttgtcc tcatgtccca cctgggccgc
cccgacggca 1800agaagaacga caagtacagc ctgaagcccg ttgttgccga
gctggagaag ctgcttggcc 1860gcagcgttgt cttcaccgag g
1881561883DNAartificial sequenceamplicon 3'pgkA A. niger
56ctccttgaga acctgcgttt ccacgctgag gaggagggca gctccaagga tgccgagggc
60aagaaggtca aggccgacaa ggagaaggtc gctgagttcc gcaagggtct gactgctctt
120ggtgatgtct acatcagtaa gtcatccttt tctcacacct tccatcttgg
gaggccacta 180gtttatgagc tgtgtactaa tattccacac cacagacgac
gctttcggca ctgcccaccg 240tgctcactct tccatggtcg gtgttgacct
tcctcagaag gcttccggtt tcctcgtgaa 300gaaggagctc gagtacttcg
ccaaggctct cgagagcccc cagcgcccct tccttgccat 360cctgggtggt
gccaaggtct ctgacaagat ccagctgatc gacaacctgc tgcccaaggt
420caacagcctg atcatcaccg gtgccatggc tttcactttc aagaagaccc
tcgagggtgt 480caagatcgga aacagtctct tcgacgaggc tggcagcaag
atcgttggcg aggtcgtcga 540gaaggccaag aagcacgacg tcaagatcgt
tctgcccgtc gactacgtca ctgccgacaa 600gttcgctgct gatgccaaga
ccggcactgc taccgacgct gagggtattc ccgacggcta 660catgggtctg
gatgttggcg agaagagtgt tgagctctac aagcagacca ttgctgaggc
720caagaccatc ctctggaacg gtccccccgg tgtcttcgag ttggagccct
tcgccaacgg 780caccaagaag accctcgatg ccgtcgtctc cgctgctcag
tccggctcca tcgtcatcat 840cggaggtggt gacactgcca ccgttgccgc
caagtacggt gtcgaagaca agcttagcca 900cgtctccacc ggtggtggtg
cctctctgga gctcctggag ggcaaggagc tgcccggtgt 960tgctgccctg
tcgagtaagt aaatttgaac aaacatatta ccactctgga tatgcggaga
1020tgctgcaaga caaaatccgt ccatgtttct ttggaggagg atgagctgtg
gttgagcttc 1080catgctcggg actagtggac aggcggcttg tgtagtacct
gtcagccttc ccggcgcccc 1140ttcaagacag ggaacaattt tacgaatgta
atgtacaaag aatgataatt aatctcaaca 1200aaatacgcgt ttaccttcat
tatcaagatg atgcaatctc atgactagtg acgggtccga 1260agctgtgagt
ctagttttat caaatgcgag ctacgaagag ggggccacaa gttgatgggc
1320ggtggacttg atcctttcag taatgggtgt gtaaataatc gtagaaagta
cataatgtgc 1380tcatgcagca catacaccgc ttccagcgaa gtgctagcct
gtaccagatc tcccaccata 1440gacgacttat cctctgcaga cgaatcctcc
acaaccacgc agctgggcta gccaccggtc 1500cggcaccgcc aaagcagacg
aatctcttac tcaaacaagt ctatctagct ccaacattgt 1560tcatcgtctc
gctaccgagc cgcgtgaggg taaagctgca cgtgtaatca agtgattaat
1620gcttcgtgga atttgcgtgt gttcatctca attaaaccga taacccgtca
tctaacataa 1680tctattgatt agacgccccg accttcttca gctcctctct
gtagtttgaa gcaaacatgt 1740tagtccaatt tgagctttag atgaggtgta
gatcaatggt aacatattgc gctcatagca 1800ttgaccgatg aggtttggtt
tggttcggtt tggttcggtt tggtttggtt cggtttggct 1860tggcttggga
aaacgtactt cag 1883571814DNAartificial sequenceamplicon 5'gsdA A.
niger 57cgttatcaca aagaagccag gtcctgagct gacctacctg catgaatggg
ctgggggctg 60ctccacaatt gccagtaaac tcgaggtgcg cgtgccccgc gcatataacc
aatgtagtac 120agcgtcagac cgcaagaaac tcggcacctc tgcatttgcg
gctttccttt gttttaattc 180cagaggataa aactgtcaga tcagggtcgg
agggttaata ttactgggat aagttgacgc 240ggggggttcc gcatgcaaca
gtaaggtgta ccttaagatg ggcatcatcc gttccatgtg 300tggttctcag
tggagctggg aggagattta cagcggacct ggctcggata aatcagtccg
360tctagaaaag aaagggctgt tagttcaaac gatcatgctt ctgaaagaca
gatagagtaa 420gtcgagtgga ggatgcttca tcgtaagcac tgatttagag
atatctagat tgtctcaagt 480ggtagatagt agagtaagac tcatcgcgtt
acctagcgat gatataagag atgggttgcc 540acaacgggct ccgaaagaga
gaaggagtac tacagtatga gtgggaacgg aggacctgac 600aatttagggg
atgaatgcta gggatgaaaa aggaagcatt tcccggagta atcataccag
660ggaaatactg gataagttga ggtaaactag caggcagtgt gtcttgagtg
atgtaaaata 720accccgaata atagaattgg ataacaacta ctactcactc
ctcacggggt cccgcggcag 780caatcgacgt agtggaagaa cccaagccgg
gcttcccagt aacaaagtag taacaaagct 840gccccacccg ggctcactca
cttttgccca ccctgcagcc agcagctcct ctcctcgacg 900agaggccctc
cggtcttaaa aagtacttgc tccgccggaa ctgttgggat ttttccaaca
960aacctctctg tccttgctgt ctccctgtat cctctttatt tcctcctctt
ccctcctcca 1020ccgaatctct cacctttcct tcccatctcg tggttgttca
cacatcagta aaacatggcc 1080agcacaatag cacgcactga ggaacgccag
aatgctgggt gagttttgcg gtctccctct 1140ctgacatcac acccctcctc
ccactcccgt ccctcctgcc cgccgcccag acgtgaggat 1200tcaccaccca
cgactctcca taacaagccc cgtcgcccaa acattcactg gcaggcttcc
1260cgctttccat tattcttcaa ttcgtcacca ggattactcc ttcgggctta
acgaaaggac 1320tatccttctg actcaccacc aaccctcact gcccctcctg
catgctgtag cggactgcgg 1380gcaccgacct gcatcatcga tctacacccg
atccctgtga cattatattc gtcaagctat 1440agcctagcta acatggatgt
tttacgtagc accatggagc tcaaagatga cactgtcatc 1500atagtactgg
gtgcctccgg agatcttgca aagaagaaga ccgtcagtga cgaccccctg
1560attcatgttg acctgacaga aagctaacct tttacagttc ccggcccttt
tcggccttgt 1620atgtcctctc ccagatccaa ttgcagtttg actcaccagt
atggttgctg atttgcgctt 1680ccagtatcgc aacaagttcc tccccaaggg
aatcaagatc gtcggatatg cccggacaaa 1740catggaccat gaggagtacc
tgaggcgtgt gcgctcatac atcaagaccc ctaccaagga 1800aatcgaagag cagc
1814581837DNAartificial sequenceamplicon 3'gsdA A. niger
58tcatcaacct caacaagcac ctcgaggaga ttgagaaggg ccagaaggag cagaacagaa
60tctactacat ggccctcccc cccagcgttt tcaccaccgt ttccgaccaa cttaagcgca
120actgctaccc caagaacggc gttgcccgta tcatcgtgag tcaatcctgg
gctggtatca 180ccctgccatt ggtcattatt cttactcgct tgttttccta
tttcacaggt agagaagcct 240ttcggcaagg accttcagag ctcgcgcgat
ctccaaaaag ccctggagcc taactggaag 300gaagaggaga tcttccgtat
cgaccactac ctgggtaagg agatggtcaa gaacatcctt 360atcatgcgct
tcggaaacga attcttcaac gccacctgga accgtcacca catcgataac
420gttcaggtac gaccttgcgc tatccaattg gcctattgat ttacttgcta
aattgtcgct 480tctatcatta gatcacattc aaggagccct tcggcactga
gggacgtggt ggttacttcg 540atgaattcgg catcatccgt gatgtcatgc
agaaccgtac gttcaaagtc acgctcgaca 600tctccgacat gatgctgata
aaaatctctc ctagaccttc tccaggtgtt gacgctgctc 660gctatggagc
gccccatttc cttctccgcc gaggacatcc gtgacgagaa ggtacagtgt
720gcgcttgact attggttgtg ctgggttact gacacttaac caggttcgtg
tcctccgtgc 780gatggacgcc attgagccca agaacgtcat tattggccag
tacggaaagt ctctggatgg 840cagcaagccc gcctacaagg aggacgagac
cgttccccag gattcccgct gccccacctt 900ctgcgctatg gtcgcctaca
tcaagaacga gaggtgggac ggtgttcctt tcatcatgaa 960ggctggcaag
ggtatgtacc tctttccaag cgatcatagc accgattggt atactaataa
1020ttcgcagcct tgaacgagca gaagaccgag atccgtatcc agttccgtga
cgttacctcc 1080ggaattttca aggacatccc tcgcaacgag ctcgttatcc
gcgtccagcc caacgagtcc 1140gtgtacatca agatgaactc caagctgcct
ggcctgtcca tgcagacggt tgtgactgag 1200ctcgacctca cctaccgccg
ccgcttctcc gacctcaaga tccccgaagc ctacgagtct 1260ctgatcctgg
atgctctgaa gggcgaccac tccaacttcg tccgtgacga tgagctggat
1320gccagctgga ggatcttcac ccctctcctg cactacctgg atgacaacaa
ggagatcatc 1380cccatggaat acccctacgg tacgtgcact tcttgcaatt
tgtctaaatc gcttacatac 1440tgaccaacgc gcaggctccc gcggacccgc
cgtccttgat gacttcaccg cgtccttcgg 1500ctacaagttc agcgatgctg
ctggctacca gtggcccttg acttccaccc ccaaccgtct 1560gtaaataagg
gcggtcggca ggttatgacg gatgaggatg aaaaaaaaat tattgccaaa
1620aaaggctaaa aaaaagatgt taatgcgatt gattttcggt cgagaatcat
ggtatgacgg 1680ggcatctggg atgatatgac agaaatgaag cactcgggac
tatttatcgg tcggctgggc 1740aataactgga gttatctatt cgcaacccct
ttttagaaac gaatgcagag aacgtaacga 1800accacccccg gtcggttggg
accgccgctg tcttcac 1837591494DNAartificial sequencepromoter PmbfA
59gccatgaaat ccaatcattt ccttctggcc gccctcgggc aagagatagt gccgcagagg
60tctctcacag catctacatc tgcgaccgca acagccacca agcgaggcgc acatgagctt
120gtcctcctcc catgccaaag tttggccctc ttcgtttctg tgatgctgaa
ggaagtcaaa 180ctcgtcgatg ataggaccag atggtttgtc aagggtcaac
gctttccatg ccttctggca 240ccggtagtaa tgctcttctg caagggagac
ttgacgtttc ggatccgcgg gccccgggac 300atgctggaag ggattttctg
gctcaatacc acgtctgtat ttgacccttt ccagacagtt 360aatccgctgc
aggagggcga actgtagctc ctcgttctcc ttgtagcgct tgatccagtc
420tttttggatg ttgcacttgc ttggcctatg cttctcatat aatcttgccc
tgtcatagag 480acgacgtctg agattgtagc gttcgtcttt gatcacccgg
agccagatag gcctgagtat 540atctgacatt agatcaaagg gtctgtggat
agtctccttc agcatcagcg acgcatgtga 600ctcgcaagtc ggagagagct
tgtgggtggt catctttgat ggcgtcctct gctttccctt 660gattttcgtt
gattgttttt cgaaagttaa gtctggcagt caagagaatc cttctgccag
720acattatatt tacgtatact gacgtagtag aaacagcgtc aggatgagga
catggtgtgt 780gctggaccac ggaatcatag ttcatcagta tattgggttg
gacaaataac gctgagcatg 840tatatgtctt tacacactat aaaagccagc
gaacgccaat aaaatagggc atattgatgt 900gaaaatatga caccagttaa
aagcagtgta ttgattttat ctctcttcac ctcggaccta 960tactaccgta
tacaagactc aacttacttc cagatatagt aatatacacc ctatggacga
1020accagcacaa taattacagc caaacaacac cacccaaatg gcatattcct
aatcagcact 1080aagcacaaat accactgtca tcacagcata atcaataaga
atcccagaca accgactcac 1140tctgactcac cttacacaaa cccccaagca
aagcgcagcc cagaacctca gccaacaatc 1200gggcaacgta cggggaaaga
ttggccgatc catgatgtca gcagccctaa cccaaagcgg 1260actagcgcat
accgcccctc
tgactccgcc atcccagggc tcgagaagct tccgtggcgt 1320cgatataaat
tcagcgggcc ttgaacatcc ctccttacga cacacctcac gcgatcgatt
1380ttgacactca cgcaccgcca ccctcacatc ctccacccac accacacccc
ttaatcaacc 1440caccatcacc gctagaacgt ctatctcatc accgacttct
catccatctt caaa 1494601498DNAartificial sequencepromoter PcoxA
60gacggcattt gagcaacatc atgcgaacgc gaccgtgtta tcagcagcca ctcagcaacc
60gtcagttcat gatatgtcgc agagcgttgt cctcggcccg ccccagatgc tcccacgaca
120ccttccagtg cagtatccac ctgccagctt cgaaatcccc cctatccagc
gcgagaaaaa 180acgccatcac tcggagaccg aagaggatgg gaaccccgac
catggcctgc ggccgcagct 240atcagtcctc tcagctgacg cccctcacga
accctcgcac tctcccgaaa tgctcttcgg 300tgtccatggc gcatcatctc
agcagcatcc catgtcaaac catggctttg ggcccacgga 360ctctgtggcc
ctgccgcaac atcaccatca ccatcgactc ccgccccatg cagcgctgcg
420cgccccaggg cgtcatggag tgaatgtgga atctcctcct ttgccctcgg
gcccgccgag 480tgtggtgggc cagcctggaa tgcctgatcc agcccccagg
cctcgaggac caaaactgaa 540gtttactccc gaagaggacg ctctactggt
gtagttgaag gaaaacaaga acttgacgtg 600gaagcaaatt gcagacttct
tcccgggccg aacgagcggt accttgcaag tccgatactg 660caccaagctg
aaggctaagg atgtagcttg gagtgacgaa atggttcgat ttgctcctga
720tgtatttcta cgcctgtctc acacatgcta atgaagggaa taggtacaaa
ggctgcagcg 780ggcaatgcac gagtacgaga acgatcggtg gcgcatcatt
gcagggaagg ttggaaatgg 840cttcacccca gctgcttgcc gcgagaaagc
catgcagctc catgagtaaa agcgttgggg 900aattttcata tttatatcta
ctgtcgccag attcggccct gcttggaccc tctgatctcc 960ttactctcca
tattggttca aatgtcgggt ctccgatagg gctggtggtg caggcttgtt
1020gtaggcacgg gaggatgatc agcataactc tgagtcacta tagggacggg
ttgatgtaag 1080gtattaagtg atgtatgata attcatttta gcccggggga
acatatggcg ccggcatttg 1140ttcgttcgca atgaaccgac actagcgtcc
gctctcgcag tttagcaccg gctgatcccg 1200ggctgaacgc ggccattgct
cggccggggc atgtgttcct tatctacggc agaccgcaga 1260agaccactgg
agcagattat agaccctaag ccctaagccg gacacccaat cgagtaggtc
1320tgcggaccag gtcactgcgg gcagccggag aagctccgca accaatcaat
ccccggcgct 1380gactaagggc aggcgaccac gggccgaagc ggcttcaaac
tcacctcaac ctccaaactc 1440cctcatctcc aaacgtcctt gccttgtctg
ccgtcattgc aacccaccca ccaggaca 1498611490DNAartificial
sequencepromoter PsrpB 61ttggcagggt cacgtagccg taattatttt
cggggaaggt tggaatgcaa tggaaggaga 60tttccgtagc tagggctttg atcgatgcgg
ggagcactgc cggtaggagg tctggggtga 120atggggtgat atgcaggcgc
ttcgtatcgg acggtgtggt cgtcatttgc ccaatagata 180gttagataga
tacctgagta cggtagcagt gcaggtgacg gctaagaagt cggagggaaa
240aaggtgcagt cacaagcgca ttcagcctaa caagtgtctt tgatactcgg
tgagaaacaa 300acttgagtag aataagacag aaagttcttg tgaatggtca
caatgggctt ccaacgaagc 360atcaagcaga ccctgttgca atagatattc
caagaccgaa aaattaatga taggatcagt 420tattggccga gggattttcc
gggccgccaa gaccgggtta tggagatgtg gcgcaggcat 480gccatcctca
gccacaggtt tctgtgacat cccaaaagca ttgatcgaag ttggtataag
540tttcattcta tctaccatgg tgacaaggaa gtacgggtgt agaaaagaaa
aatctggtag 600gaatagctca gcaacaaatg gcggaatgat tgatgtaaga
ctcgatgtat ccactggaac 660gagatgcaag ttgcaacagc aataaatgga
tttcagcctc cattacaatg taacagtcgg 720gccgatactc agccggagca
ggatttggcg ggtgaatagt ggatccggag agaaacgacc 780aggtaatctt
tcgtacggga ccagacccga cccggcctgc tttttagtta ccagctgtta
840cttgtgtaat ccccgtaaaa cgatcagtaa ctgccattga tcttcctgct
cttttccctt 900attccctttt ccccctttga aacttatttt cttcttcctc
ttcatcgctt aactacttaa 960gtactaggat tctcactcgc cactcttccc
caatatctaa aagtagtctt gctacgaaga 1020tcccttcccc ctacattact
cctcctcctt caacacaccc acccccccct gatccggccc 1080cataccagtc
ttcccgcggc taactaaagc ccgcacgtct gatctcatcg ccgcttccag
1140cttcgacctc agtcgctcac atggccactc ggattcctta gcatcatctc
tttttttccc 1200atcccctccc cgccctacca actgagggtc ctctgaagtg
tgctccacat ttccttccct 1260tcacttattt tggatcctca ttttctttct
tcctctgttt cggggcgttc ttcaacatcg 1320ctacttagtc acttctctcc
tctcattacc ggacgggaac ttcgctccct tctccgcttt 1380cttatccgga
ccgcctcttg ccaatctcac catcgatcct aacccgtcat aatccagtca
1440ctcaacccta ctattgtcga catacacgtc ggttcccatt ctcgttcgag
1490621500DNAartificial sequencePpromoter PtvdA 62ttagtccatt
cagcaagctg ccgttgggat ccttggcttc agccgtcaag ggctggcctc 60gcttgagcgg
ctctttgctg aggaacacgg agaaaaagag gttagctgtc tgccagcaga
120gaaccaggag gcctcctgaa atcaaggttc gcacgataac tccgaggatt
ggcgggataa 180tgccgggagg ggatgcagcg gatctcggga aatcccagaa
tagctttgca aagtacagtg 240tagtgctcca tgccgggcgc cggaggacga
aggcgtatgc gaatgggcaa agaatggaaa 300ccaagatact ccgtttcatc
ccatctttga tgagctgcgg caatgctgac tggaggcgtt 360tagagatcga
ttgctcctgc cggctatctt catcagcgga gccagcgacc ctcctggcaa
420cgggaagagg gacgcgatcg tagtcgtagt aaagatgaac cactgactgc
gcgactgcca 480ggagaaagtg gtaggtataa aggtagattg ctctttcgtt
taagcttgct cgttcgtgag 540gtctagcata actagttagg cgagttcaag
agaaccgctt gagctcgtcg tcgcaggaaa 600catacctagc tcggttcacc
aattccaggt gtgcgctact tgaagaagac cacctgtaga 660tttcagtgaa
ccaccaggcg gagaacaagt accagccaaa agtctgtata acgtcgaggg
720gaacgaggta tttgaaggtg ctaagcgggg aggaggttgt cctggcaccg
atgtgcatct 780gaccaacacg gaggacgaag acaacgagac tgcagaggaa
gagaagaact gtgcgaactc 840cacatcctcc aatggggaac caagcccaca
agactatcga gatatcacag ctggttagcg 900atcacagctt gtcaaacgcc
gctcggtgtt ggtgtaaact tacaagatga cttatcgcca 960atagcaaatg
ccactacata gcagaccaga agcgccagtg ccgacgcatg aacgaatcgt
1020ctgtgcagcg cagaggtcaa gatgcgccga tacgggcgag gctgtgctgc
agccatggtg 1080caaggtggaa gagggactgt gagatctcta gggagagaag
agacaaagca atttcactgc 1140atgatcagat gacaggagga attgaggtat
ccggtcagcc tgtcagaacg gaaagctccg 1200aaggggggca agtggagctt
caaggaggag tgtcggcgtc ggatgcgaca ataaagtgaa 1260gcttttcggg
caaagcatca aaacacgcac cagccacaaa cggcatgtca tgtgacaccc
1320caccagccat cgatggcgtc aggtgagtgg cagcctgcga atcatggcat
ctgtgcggcc 1380aggcaaccgt cgacacctga cagcgataac gtactactac
tttagcaggg agagagccgg 1440ccggttgcat cggccgaatg atcccacctt
catccatcca ctgtcgcatc tcattccgcc 1500631064DNAartificial
sequenceterminator TglaA 63cgaccgcgac ggtgactgac acctggcggt
agacaatcaa tccatttcgc tatagttaaa 60ggatggggat gagggcaatt ggttatatga
tcatgtatgt agtgggtgtg cataatagta 120gtgaaatgga agccaagtca
tgtgattgta atcgaccgac ggaattgagg atatccggaa 180atacagacac
cgtgaaagcc atggtctttc cttcgtgtag aagaccagac agacagtccc
240tgatttaccc ttgcacaaag cactagaaaa ttagcattcc atccttctct
gcttgctctg 300ctgatatcac tgtcattcaa tgcatagcca tgagctcatc
ttagatccaa gcacgtaatt 360ccatagccga ggtccacagt ggagcagcaa
cattccccat cattgctttc cccaggggcc 420tcccaacgac taaatcaaga
gtatatctct accgtccaat agatcgtctt cgcttcaaaa 480tctttgacaa
ttccaagagg gtccccatcc atcaaaccca gttcaataat agccgagatg
540catggtggag tcaattaggc agtattgctg gaatgtcggg gccagttggc
ccggtggtca 600ttggccgcct gtgatgccat ctgccactaa atccgatcat
tgatccaccg cccacgaggc 660gcgtctttgc tttttgcgcg gcgtccaggt
tcaactctct ctgcagctcc agtccaacgc 720tgactgacta gtttacctac
tggtctgatc ggctccatca gagctatggc gttatcccgt 780gccgttgctg
cgcaatcgct atcttgatcg caaccttgaa ctcactcttg ttttaatagt
840gatcttggtg acggagtgtc ggtgagtgac aaccaacatc gtgcaaggga
gattgatacg 900gaattgtcgc tcccatcatg atgttcttgc cggctttgtt
ggccctattc gtgggatgcg 960atgccctcgc tgtgcagcag caggtactgc
tggatgagga gccatcggtc tctgcacgca 1020aacccaactt cctcttcatt
ctcacggatg atcaggatct ccgg 106464549DNAartificial
sequenceterminator TniaD 64acgggttcgc ataggtttgg ggttgtatct
tggcgttggg acggactggg tatggtgttt 60cttttggata tatgacatga tatgtacacg
gccgtgaatc tttaacttta tatcattata 120gaaatgcact tgcacatttc
aacacgctgc gagcagaatc tcgaagattg ttccgcaagt 180attagatcat
gagagcattt tcatttcctt tcaggcagtg ggagtaggcc atcctgaaaa
240caaggcggcc actgtagact agtaatacct cttcatatcc aaccttacca
gaagatgatc 300aaacacattc gcagatccac ctctcgccgc gaaagccatc
ccggcccttc cggtacccaa 360tgcctttgat gacgatgcca ccgcccccct
ggcaccatct aggctacgca aatacccaac 420aaaagcggcc atttgcttcc
taaacactgc atacaaccgc ttgaccatgg cttcactctc 480gtgcctcacg
ccatgtgtcc catccttgcg cgacagaggc gcaaacctca gaatcgtgtc 540aaatatccc
54965580DNAartificial sequenceterminator TgpdA 65gaatcaggac
ggcaaactga attcagaagt gtgctgtgag tgagactgat tgccgagcgc 60agacgactct
cgtggaaccc ggcttgtgga gaagcttgag aaggtcttaa ctcctagcgt
120aaaagctcat gatgacgtac aatttaatga aatgatacaa tgttcatatt
tcccgttcaa 180atttccggcc ttggtcagtg cgtaagatgt ccacgattga
atactaactc agtatgggtt 240tggtagcatt ggcaatgtag ttataagcat
gcaccggttg aagacgtcgg ccccagatgc 300aatgctgcgg tggtgactaa
gctctgcagt gaatggaatg cgtttctttg atcgacttcg 360gcgtgccgcg
ggattttctc ggcgcttcta ctggtgcaga aaggacgata ccactggctt
420tcggtccatg ccacatccca gtctcccggg aaattcattg catactttaa
gaaacaaact 480gatctccata atttccgtct ttagagttca cttggtactt
ttgggtggat cgaggggtgt 540ccgcggccat ccaagtcacg tggagggcag
ctagaccacg 58066528DNAartificial sequenceterminator TtrpC
66tgatttaata gctccatgtc aacaagaata aaacgcgttt cgggtttacc tcttccagat
60acagctcatc tgcaatgcat taatgcattg gacctcgcaa ccctagtacg cccttcaggc
120tccggcgaag cagaagaata gcttagcaga gtctattttc attttcggga
gacgagatca 180agcagatcaa cggtcgtcaa gagacctacg agactgagga
atccgctctt ggctccacgc 240gactatatat ttgtctctaa ttgtactttg
acatgctcct cttctttact ctgatagctt 300gactatgaaa attccgtcac
cagcccctgg gttcgcaaag ataattgcac tgtttcttcc 360ttgaactctc
aagcctacag gacacacatt catcgtaggt ataaacctcg aaaatcattc
420ctactaagat gggtatacaa tagtaaccat ggttgcctag tgaatgctcc
gtaacaccca 480atacgccggc cgaaactttt ttacaactct cctatgagtc gtttaccc
528671713DNAartificial sequenceamplicon 5'pgkA A. terreus
67cttggggaat tgggacacgc caggaaccta ccgcccccgt ttgattttga gcggttgacc
60cgtttcatgt cgtacggttt cttcatggcc ccggtgcagt tccagtggtt cgggttccta
120tcgaggacct tccctctcac caagaagaac ccgaccatcc cggctctgaa
gcgggtggcg 180gttgatcagc ttatgttcgc tccgttcggt atggacctga
tgttgtgcca cgagaaaaag 240gatatcccgc taatagaaat gaatataggt
ctggtctgtt tcttcacctt catgacaatt 300gctgagggtg gcggacggag
agccttgact cgcaagttcc aggatgtgta cctgccgaca 360ctcaaggcga
actttgtgct ctggcctgcg gtgcaaatcc tgaacttccg ggtggttccc
420atccaattcc agattgtgag tttgctcttc tcccgtgacc cgacgcgttt
tcattagtta 480ttgtatactg attgcttttt ctttcacagc catttgtgtc
gtcggtgggt atcgcatgga 540ccgcatacct gtctctgacc aactcttccg
aggaggagta aggtaaggta cgggttttct 600cgttgcattg gatggttatc
acttgatacc tatgtttacc tggtcggccc ttggctttgg 660aaatcttctt
tgtggattct ttcttctttc cttgtgttgc gtggggtatg tttacggcgt
720tttcaatgct gttttggggg gttctgtttc tcattggtgg tgtccggtct
gtcacagggt 780actctcaaag gtttcttcgt taggtattca aaaggcgcac
aaatgctgga tttagatcat 840caacccaagc ggaagagact attcaaagga
gtctccattc gcagggatat ggaactgcca 900ttctatgacg ctttcgggag
aaatttccag gattttcgta ggtcgagaca cccacagagg 960cacatgtagg
gaccgcgggg gacgatgatc ctatgaatgc ccgtacgacg agaattccga
1020agcggctgtt tccaattccc gcgagagatc cgaggctatc gagaacgcat
agggacaatg 1080ttcacccctg agagcccgga cccttccgtc atcgatcgcg
gtggactgac atcagtcccg 1140catcagcccg atgcgtcagc gaatctctca
ccggacgccc caccaaacac tgctgctacc 1200ccgccgctgg gccgaagtta
tcatatgggc tcaccgtgaa cggattgagc atttttccct 1260ccttcttcca
attcacctca ccatctctcc tgcgaggtac tgctccctat ttctatccct
1320ctagacccct gtggtatcgc tgacccgacg ccagctcctc cctctccaac
ttcttcacca 1380tgtctcttag caacaagctt gccatcactg acgtcgacct
caaggacaag cgtgtcttga 1440tccgggtatg tcacctccaa tggctgtggt
atgatcggtc aatgctaacc acgctcacct 1500cccaggtcga cttcaacgtc
cctctcgatg acaacaagaa cgtcaccaac ccccagcgta 1560tcgttggtgc
tctccccacc atcaagtacg ctgtcgagaa tggcgccaag gccgttgtcc
1620tcatgtccca cctcggtcgt cctgacggca agaagaaccc caagtacagc
ctgaagcccg 1680tcgtgcccgt cctggagaag ctcatcggca aga
1713681820DNAartificial sequenceamplicon 3'pgkA A. terreus
68cagatcatcc tcctggagaa cctgcgtttc cacgccgagg aggagggcag ctccaaggac
60gccgagggca agaaggtcaa ggccgacaag gccgccgtcg aggagttccg caagggactg
120accgctcttg gtgacatcta catcagtaag tctatttccc ctttggccca
tggaccgtaa 180ttgggtttgt ccatactaac gataccatcc agacgatgcc
tttggaaccg cccaccgtgc 240ccacagctcc atggtcggcg tcgacctccc
tcagaaggct tccggcttcc tggtgaagaa 300ggagcttgac tacttcgcca
aggccctcga gaacccctct cgtcccttcc tggccatcct 360cggtggcgct
aaggtctccg acaagatcca gctgattgat aacctcctcc ccaaggtcaa
420cagtctgatc atcaccggag ccatggcctt taccttcaag aagaccctgg
agaacgtcaa 480gatcggcaag agtcttttcg acgaggccgg cagcaagatc
gtccccgaga tcgtcgagaa 540ggctaagaag aacaacgtga agatcgtcct
tcctgtcgac tacgtcactg ccgacaattt 600cgctgccgac gccaagaccg
gctacgctac cgatgccgac ggcatccctg acggcttcat 660gggtctggat
gtcggcgaga agagtgtcga gctgtacaag cagactatcg ccgaggccaa
720gacgatcctc tggaacggcc cctgcggtgt cttcgagatg gagcccttcg
ccaacggcac 780caagaagacc ctcgacaacg tcgttgccgc cgctcagtcc
ggctccattg tcatcatcgg 840tggtggtgac actgctaccg tggccgccaa
gtacaacgcc gaggacaagc tcagccacgt 900ctccactggc ggtggtgcct
ctctggagct tctggagggc aaggagctgc ctggtgtcac 960tgctctgtca
agtaagtaaa cttttacgac catgtaatgt gttggaggga cgagttgcag
1020aatgagatcg tgcttgtcca tgtgtattgg gcgagccatg gctgcatcag
gccgtgtttt 1080tttagcgtcc ctctccatcc cgtcgaggga tggccttttc
tatgatgtaa tgtacaggca 1140ttaaaattaa tcaaaataag cgaaatgatt
ttgtttctcg attcaagaag ggttctgatg 1200aagtaatggc tactagtgac
gggatctaaa ctgtgagatc agacgcttgt cgttcccatt 1260gaaatggata
ttcttattgc gtagagcttc tcttatcttt tctatcaaac aattgttttc
1320ataggatgtc cgggagccat acaccgccag cgtccgtcac gatcatatat
gcctggtaga 1380tctgggccaa ggaccccggt cgcttctcca gtgggctggg
cgccgttccc cttgacgaac 1440gaacggccat gacgatccca ggtgaacgca
aggccgggcg aactaccacc atagaacgga 1500catgatgtcc taataaagaa
gaatgtagca tcttgatgat atagcttgtg ttccatcatg 1560gaaaaagagg
gcaaaaatag ataattctta tcgttcgttc attcgcgttc gggatattca
1620gagtaccaca tgtccatccg tccattagtg agatgcctcg accttttcca
gttcctctct 1680gtagcacgaa gagaaatacg ttagtgttgc gtaggcgtca
gaggaagaag gggagcaacc 1740gcactttagc tgtttcgaaa agtcctccgc
cgcatcgtcg tcgtcccagc tctcctccca 1800caggtgaaca ttcgtgccgt
1820691817DNAartificial sequenceamplicon 5'gsdA A. terreus
69attggaagct ggctctatct cacccctcct gacgaagacc tcagcagtgt acggtacact
60ggagttaagc tgtccgtctc cgcggacacc tgacgagctt agatagaggg tgggttggat
120tatggaccac accccggccg cctttatatt tctttttctc cttttttgat
gtcctggcct 180tcgcctatca gaggagaatc ccactagatc ctaaactgac
tgggcgtaag attactagta 240ccatgtagca tttggcgcgg ggctaggagg
tcagcatatc caagatgtgc ctctagagat 300gcgtctccgg tccatgtacg
gttcccggtg gagctcactg ggttgaaatt tccagcggag 360taggctcgga
taaaactagt gttaagaagc agttgagcag aagggttcgg atgattgggg
420acggtagtaa tacaaggtac aagcaccggc atcgggaagg atttccttcg
tgtcctctat 480atccgagtgg gagggagtat gaacgggctg actgagtacc
taggcaggcg tgagagggat 540gatataatac cagtagctgt cgccacggcg
gtggattcta gggagtaact actacgtaga 600tgatgaaaag gaaaaagaac
tgataaaaga tgacagatta tctatctccg gaaaaagggc 660gggcacccga
ggctatagtt atactacgaa gcataaataa aataataaaa acacctaatt
720aaatccaaca cgaagatatc ctaggttccc aaagcccagt tgtatgtaat
ttctctccag 780ttaggttttt tcttacccag gccaccggac ggggctcgcg
gcaacaatcg acgccccacc 840gtgtactgta atcgagagtc accctgcagc
aactgcagct cctcgactgc tgctacgact 900aagcagagtc cctctcacgg
cgttaaaaag tacttgctcc gccggaactg ttggggattt 960ttccaacaaa
cctcttctct ttcctcctct actccctcgt ctctccttca ttccaagctt
1020catttccctt ccttaacagt ccgttgttca tttttggtgc ctgcacaaac
tcccgtccgt 1080caccatgacc agcacaatag cccgcactga ggaacgccag
aacgctgggt gagtcttgac 1140tgccgccgcc gcctccctct ctgacatcac
acccctcctc cgtccccctc tacgtctttc 1200ttttcttccc acccgtctgc
cacctgctcg atcgccttcc tcaggacagt caatatcagt 1260caattcgacc
ccagattttc cacttccctt cgttgaatgc cccgagctct tccaatttgc
1320tttttagaaa ttgtcgagca gctctagttt tcaattcccc cttcttccga
tcgcgctggc 1380aaatccctgt gatcgacatc atacagcttc ccctgctcag
ccagtaacct tcgattcgct 1440actaacatgg atgtctcgcg tagcaccatt
gaactgaaag atgacacggt catcgtggtc 1500ctcggtgcct ccggagatct
cgcaaagaag aagacggtag gtgttctacc ctaaaaaggc 1560ttggccggtg
aagccgatcg gagactgact aggttccata gttccctgca ctgttcggtc
1620ttgtaagtat acgatgacgg tccgagtaaa gtatcgtcgc gtcggttggc
attgaccatg 1680catttagtac cgtaacaaat tcctccccaa ggggatcaag
atcgtcggat atgctcggac 1740gaacatggac cacgaagaat atctgagacg
ggtgcgctcg tacatcaaga cccccaccaa 1800ggaaatcgaa gaacagc
1817701825DNAartificial sequencesynthetic oligonucleotide
70tcaacctcac caagcacctc gaggacgtcg agaagggcca taaggaacag aacagagtct
60tctacatggc gctgcctcct agcgtcttca ttaccgtgtc ggatcaattg aagagaaact
120gctaccccaa gaacggcatt gcccgtatta ttgtgagtcg ccaacacaaa
agctttgttt 180ctaccgaggc atatgcttac gcgtgttttc tttgtgtcta
caggtcgaga agcccttcgg 240caaggatctc cagagttctc gtgacctcca
gaaggccctt gagcccaact ggaaggagga 300ggagatcttc cgtattgacc
actacctggg taaggagatg gtcaagaaca ttctcatcat 360gcgcttcgga
aacgagttct tcaacgctac ctggaaccgt caccacattg ataacgtgca
420ggtatgagtt gaatgttttc aggacgaccg gtgcagatgc taagctcttg
tcgcagatca 480cattcaagga gccgttcggc acggagggcc gtggaggtta
ctttgatgag ttcggcatca 540ttcgtgatgt catgcagaac cgtatgtcca
acaaaaaaat gaccttgacg gctaatgatg 600gcaagtgcta atgtccttat
ctagaccttc tgcaggtgtt gacgcttctt gccatggagc 660gtcccatctc
tttctctgct gaagacattc gtgatgagaa ggtatttttg ccgatccctt
720atcccaccgg cggcaactaa cgtaagtgac aggtgcgtgt tctgcgcgcg
atggacccca 780ttgagccaaa gaacgtcatc atcggccagt acggaaagtc
gctcgacggt agcaagcccg 840cctacaagga ggatgatact gtccctcaag
actcgcgctg cccgactttc tgcgccatgg 900ttgcgtacat caagaacgag
agatgggatg gcgttccctt catcatgaag gccggtaaag 960gtatgtatcc
tgttctctat ggcagcacgc cctggacttg gtgtactcac atcttcgaca
1020gccctgaacg agcagaagac cgagatccgt atccagttcc gtgacgtcac
ttccggcatc 1080ttcaaggaca tcccccgcaa cgaacttgtt attcgcgtcc
agcccaacga gtcggtgtac 1140attaagatga actccaagct gccgggtctc
tccatgcaga cggtcgttac cgagcttgac 1200cttacctacc gccgccgttt
ctccgacctc aagatcccgg aggcttacga gtctctgatt 1260ctggatgctc
tgaagggtga ccactcgaac tttgtccgtg acgatgaact tgactcgagc
1320tggaagatct tcacccctct gctgcactac ctggacgaca acaaggagat
catccccatg 1380gaatacccct acggtaagcg gcgaatgcgc catctgcgaa
acaaaatatt tcttttgagt 1440tccagtactg acaatgttat caggctctcg
cggacctgct gtgctcgacg acttcaccgc 1500atcgttcggg tacaagttca
gtgatgctgc tggctaccag tggcccctga cttcggcccc 1560caacagactg
taaatgaaaa atattatgat cgtttaagca atgaaaaggg aaagaaggaa
1620aatgggttaa tgtgagcact accgggtttc atagcatgat cggatggtcc
tcgaggttgg 1680gatggcacga tatttggaga cgggttttcc agatcggcca
tggtggacca gacgctcccc 1740tgggtcccta gaaacgaatg aagtgactgt
tacgaatcaa acacgatgat attgattccc 1800tcttgcagtt gcgacgggct gtttg
1825711731DNAartificial sequencesynthetic oligonucleotide
71atggaattca gagtccactt acaagccgat aacgaacaaa agatattcca aaaccaaatg
60aaaccagaac cagaagcctc ctacttaatt aatcaaagaa gatcagctaa ctacaagcca
120aacatctgga agaacgattt cttggatcaa tcattgatct ctaagtacga
tggtgacgaa 180tacagaaagt tatcagaaaa gttgatcgaa gaagttaaga
tctatatttc tgctgaaact 240atggatttgg ttgcaaagtt ggaattgatc
gattctgtta gaaagttggg tttagctaat 300ttgttcgaaa aggaaattaa
agaagcattg gattcaatcg ctgcaatcga atctgataat 360ttgggtacta
gagatgattt gtacggtaca gctttgcatt tcaagatttt gagacaacat
420ggttacaaag tttcacaaga tatcttcggt agattcatgg atgaaaaggg
tactttggaa 480aaccatcatt tcgctcattt gaagggcatg ttggaattgt
tcgaagcatc taatttgggt 540ttcgaaggtg aagatatctt ggatgaagct
aaagcatcat tgacattagc tttgagagat 600tctggtcata tctgttaccc
agattcaaat ttgtctagag atgttgttca ttcattagaa 660ttgccatctc
atagaagagt tcaatggttc gatgttaagt ggcaaattaa tgcttacgaa
720aaggatatct gtagagttaa cgctactttg ttggaattgg caaagttgaa
cttcaatgtt 780gttcaagcac aattgcaaaa gaatttgaga gaagcttcta
gatggtgggc aaatttgggt 840atcgctgata atttgaagtt cgctagagat
agattggttg aatgttttgc ttgtgcagtt 900ggtgttgcat tcgaaccaga
acattcttct tttagaatct gtttgacaaa agttattaat 960ttggttttga
ttattgatga tgtttatgat atctatggtt cagaagaaga attgaagcat
1020ttcactaatg ctgttgatag atgggattct agagaaacag aacaattgcc
agaatgtatg 1080aagatgtgtt tccaagtttt gtacaacact acatgtgaaa
tcgcaagaga aatcgaagaa 1140gaaaatggtt ggaaccaagt tttgccacaa
ttgactaagg tttgggcaga tttttgtaaa 1200gctttgttgg ttgaagcaga
atggtacaat aagtcacata tcccaacatt ggaagaatac 1260ttgagaaacg
gttgtatctc ttcatctgtt tctgttttgt tggttcattc tttcttttct
1320atcactcatg aaggtacaaa ggaaatggct gatttcttgc ataagaacga
agatttgttg 1380tacaacatct cattaattgt tagattgaat aatgatttgg
gtacttcagc tgcagaacaa 1440gaaagaggtg actctccatc atctatcgtt
tgttacatga gagaagttaa tgcttctgaa 1500gaaacagcaa gaaagaatat
caagggtatg atcgataacg cttggaagaa agttaacggt 1560aaatgtttca
ctacaaacca agttccattt ttatcatctt ttatgaataa tgcaacaaat
1620atggctagag ttgcacattc tttgtacaaa gatggtgacg gttttggtga
ccaagaaaaa 1680ggtccaagaa cccacatatt atcattatta ttccaaccat
tagtaaactg a 1731
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