U.S. patent application number 10/459315 was filed with the patent office on 2004-12-16 for fermentation processes and compositions.
This patent application is currently assigned to Novozymes North America, Inc.. Invention is credited to Grichko, Varvara.
Application Number | 20040253696 10/459315 |
Document ID | / |
Family ID | 33510794 |
Filed Date | 2004-12-16 |
United States Patent
Application |
20040253696 |
Kind Code |
A1 |
Grichko, Varvara |
December 16, 2004 |
Fermentation processes and compositions
Abstract
The present invention provides improved fermentation processes,
including for use in an ethanol production process. The improved
fermentation processes include applying at least one fatty acid
oxidizing enzyme (such as a lipoxygenase) in a fermentation
process. The improved fermentation process may also involve the
addition of various additional enzymes and growth stimulators for
the fermenting microorganisms, including vitamins and mineral.
Inventors: |
Grichko, Varvara; (Raleigh,
NC) |
Correspondence
Address: |
NOVOZYMES NORTH AMERICA, INC.
500 FIFTH AVENUE
SUITE 1600
NEW YORK
NY
10110
US
|
Assignee: |
Novozymes North America,
Inc.
Franklinton
NC
|
Family ID: |
33510794 |
Appl. No.: |
10/459315 |
Filed: |
June 10, 2003 |
Current U.S.
Class: |
435/161 |
Current CPC
Class: |
Y02E 50/10 20130101;
Y02E 50/16 20130101; C12P 7/10 20130101; Y02E 50/17 20130101; C12P
7/06 20130101; C12P 7/08 20130101 |
Class at
Publication: |
435/161 |
International
Class: |
C12P 007/06 |
Claims
1. A process for producing a fermentation product in a fermentation
medium which process comprises a fermentation step, comprising
subjecting the fermentation medium to at least one fatty acid
oxidizing enzyme.
2. The process of claim 1, wherein said fatty acid oxidizing enzyme
is a lipoxygenase.
3. The process of claim 1, wherein said fermenting microorganism is
a yeast.
4. The process of claim 1, wherein said fermentation product is
ethanol.
5. The process of claim 1, wherein fermentation step which is part
of a simultaneous saccharification and fermentation process (SSF)
or a liquefaction, saccharification, and fermentation process
(LSF).
6. The process of claim 1, wherein the fermentation is carried out
in the presence of one or more enzymes selected from the group
consisting of an esterase, phytase, cellulase, xylanase, laccase,
protease, alpha-amylase, and glucoamylase.
7. The process of claim 1, wherein the fermentation is part of a
dry milling process or of a wet milling process.
8. The process of claim 7, wherein the raw material for milling
process is a starch-containing raw material, such as corn, wheat,
barley, or milo.
9. A process for producing ethanol, comprising (a) milling whole
grains; (b) liquefying the product of step (a); (c) saccharifying
the liquefied material; (d) fermenting the saccharified material
using a microorganism, wherein the fermentation process further
comprises contacting the fermentation media with at least one fatty
acid oxidizing enzyme.
10. The process of claim 9, further comprising distilling the
fermented material.
11. The process of claim 9, wherein said process is a simultaneous
liquefaction and saccharification process (SSF) or a simulataneous
liquefaction, sacchariifcation and fermentation process (LSF).
12. The process of claim 9, wherein said process comprises adding
one or more enzyme from the group of esterase, such as lipase or
cutinase, phytase, cellulase, xylanase, alpha-amylase, glucoamylase
or mixtures thereof.
13. The process of claim 9, wherein said fatty acidi oxidizing
enzyme is a lipoxygenase.
14. The process of claim 9, wherein said microorganism is a
yeast.
15. A composition comprising a fatty acid oxidizing enzyme and one
or more enzymes selected from the group consisting of an esterase,
phytase, cellulase, xylanase, laccase, protease, alpha-amylase,
glucoamylase, and mixtures thereof.
16. The composition of claim 15, wherein the fatty acid oxidizing
enzyme is a lipoxygenase.
17. The composition of claim 15, further comprising a lipase.
18. The process of claim 2, wherein said lipoxygenase is derived
from Saccharomyces cerevisiae, Thermoactinomyces vulgaris, Fusarium
oxysporum, Fusarium
Description
FIELD OF THE INVENTION
[0001] The present invention relates to enzymatic processes and
compositions for producing fermentation products, including
processes and compositions for improving yeast performance during
fermentation processes.
BACKGROUND OF THE INVENTION
[0002] Fermentation processes are used for making a vast number of
commercial products, including alcohols (e.g., ethanol, methanol,
butanol); organic acids (e.g., citric acid, acetic acid, itaconic
acid, lactic acid, gluconic acid); ketones (e.g., acetone); amino
acids (e.g., glutamic acid); gases (e.g., H.sub.2 and CO.sub.2),
and more complex compounds, including, for example, antibiotics
(e.g., penicillin and tetracycline); enzymes; vitamins (e.g.,
riboflavin, B.sub.12, beta-carotene); hormones, and other compounds
which are difficult to produce synthetically. Fermentation
processes are also commonly used in the consumable alcohol (e.g.,
beer and wine), dairy (e.g., in the production of yogurt and
cheese), leather, and tobacco industries.
[0003] There is a need for further improvement of fermentation
processes and for improved processes which include a fermentation
step.
SUMMARY OF THE INVENTION
[0004] The present invention provides processes and compositions
for producing a fermentation product. The present invention also
provides improved processes for producing ethanol using one or more
of the processes described herein. According to the invention the
percentage of (recycled) backset, as will be defined further below,
in the fermentation medium may be increased significantly leading
to a reduced need for feeding additional water to the fermentation
process. Further, the more efficient utilization of the
fermentation material reduces the cost of the fermentation process,
because more starch-containing starting material is converted into
fermentation product, such as ethanol, and carbohydrate nutrition
for the fermenting organism(s).
[0005] In the first aspect the invention relates to a process for
producing a fermentation product in a fermentation medium, which
process comprises a fermentation step, comprising subjecting the
fermentation medium to at least one fatty acid oxidizing
enzyme.
[0006] In one embodiment of the present invention at least one
fatty acid oxidizing enzyme is applied to the fermentation medium
before or during fermentation. In a preferred embodiment, the
invention comprises contacting the fermentation medium with at
least one fatty acid oxidizing enzyme. The fatty acid oxidizing
enzyme may in one embodiment be used to pre-treat the backset
before recycling it to the fermenter/fermentation container. In
another embodiment the fatty acid oxidizing enzyme treatment is
performed directly on the fermentation media with or without the
backset portion. In a preferred embodiment the fatty acid oxidizing
enzyme is added directly to the fermentation medium comprising
recycled backset. In an embodiment the fatty acid oxidizing enzyme
is added before or during fermentation process. The fatty acid
oxidizing enzyme may be added to the fermentation medium before the
addition of fermenting organism(s), such as yeast, but may also be
added together with or after addition of the fermenting
organism(s). It is preferred to add the fatty acid oxidizing enzyme
before the initiation of the fermentation. However, it is also
within the scope of the invention to add the fatty acid oxidizing
enzyme during fermentation, such as after initiation of the
fermentation. In a preferred embodiment the fermentation medium
comprising a backset portion is pre-treated with a fatty acid
oxidizing enzyme.
[0007] The fatty acid oxidizing enzyme may be applied in an
effective amount before and/or during fermentation. The fatty acid
oxidizing enzyme may be applied in an effective amount before
fermentation, such as, during propagation of the fermenting
microorganism(s) or after propagation of the fermenting
microorganism(s).
[0008] In a preferred embodiment of the present invention the fatty
acid oxidizing enzyme is a lipoxygenase. In a preferred embodiment
the fermenting microorganism is yeast.
[0009] In an embodiment, the fermentation process of the present
invention is used in combination with a saccharification step (SSF)
or both a liquefaction step and a saccharification step (LSF). In
addition to at least one fatty acid oxidizing enzyme other
enzymatic activities may be added. Such enzyme activities include
esterase activity, preferably lipase and/or cutinase activity,
laccase activity phytase activity, cellulase activity, xylanase
activity, alpha-amylase activity or glucoamylase activity.
[0010] In a preferred embodiment, the fermentation process is used
for producing an alcohol, preferably ethanol. The presence of at
least one fatty acid oxidizing enzyme may be used to raise the
ethanol yield. By using at least one fatty acid oxidizing enzyme in
accordance with the invention it is possible to increase the
percentage of (recycled) backset in the fermentation medium. The
backset may constitute up to 30% w/w, preferably up to 50% w/w,
more preferably 70% w/w, and even up to more than 90% w/w of the
liquid portion (i.e., backset and water portions) of the
fermentation medium before initiation of the fermentation. In other
words this means that for instance recycling of 50% w/w backset
corresponds to a fermentation medium (slurry) comprising 64% w/w
(ground) grain material, 32% w/w water and 32% w/w backset.
[0011] The term "backset" refers to the liquid portion obtained
from the co-product (i.e. whole stillage) coming from the
fermentation step--after dividing (separating) the fermentation
coproduct (i.e., whole stillage) into a solid portion (i.e., wet
grains) and a liquid "backset" portion. The "backset" portion is
sometimes referred to as "thin stillage". Backset comprises about
10% solids and usually contains various compounds that are
inhibitory to fermentation process and thus may lead to a decreased
ethanol yield. Therefore, the addition of backset is in general
avoided.
[0012] According to the invention this problem may be overcome by
subjecting the fermentation medium to at least one fatty acid
oxidizing enzyme. In a preferred embodiment the fermentation is
performed in the presence of one or more additional enzyme
activities. The additional enzyme(s) may be introduced prior to,
during/simultaneous with or after the fatty acid oxidizing enzyme.
The fatty acid oxidizing enzyme may be used in combination with one
or more of the following enzymes: esterase, such as lipase and/or
cutinase, phytase, laccase, protease, cellulase, xylanase, amylase
and/or glucoamylase, of mixtures thereof.
[0013] In another embodiment of the present invention stimulator(s)
for growth of the fermenting microorganism is(are) added/present in
combination with the fatty acid oxidizing enzyme and optionally an
additional enzymatic activity described herein, to further improve
the fermentation process. Preferred stimulators for growth include
vitamins and minerals.
[0014] In a final aspect the invention relates to a composition
comprising a fatty acid oxidizing enzyme and an additional enzyme
and/or a stimulator.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The present invention provides processes and compositions
for producing a fermentation product in which at least one fatty
acid oxidizing enzyme is used in the fermentation process.
[0016] Treatment of the fermentation medium with a fatty acid
oxidizing enzyme prior to or during fermentation increases the
fermentation yield. Further, treatment of the fermentation medium,
which includes a portion of backset, with a fatty acid oxidizing
enzyme increases the fermentation yield compared to the yield
obtained without addition of the fatty acid oxidizing enzyme. The
addition of one or more further enzyme activities results in
further fermentation yield improvements.
[0017] Although not limited to any one theory of operation, the use
of a fatty acid oxidizing enzyme in the fermentation processes
according to the present invention is believed to be based on the
increased starch release, due to disruption of amyloplast
membranes, from the grain material. Also, the fatty acid oxidizing
enzyme promotes the formation of S--S bridges in proteins. This is
believed to increase the slurry stability.
[0018] In the first aspect the invention relates to a process for
producing a fermentation product in a fermentation medium, which
process comprises a fermentation step, comprising subjecting the
fermentation medium to at least one fatty acid oxidizing
enzyme.
[0019] The fatty acid oxidizing enzyme treatment may be applied at
any stage in the fermentation process. In a preferred embodiment,
the fatty acid oxidizing enzyme is added, in an effective amount,
during fermentation (e.g., by contacting the fermentation medium),
such as, at the start of the fermentation process. In another
preferred embodiment, the fatty acid oxidizing enzyme is added in
an effective amount prior to fermentation, such as, during
propagation of the fermenting organism(s) or after propagation or
during a saccharification or a pre-saccharification step or
liquefaction step. The fermentation process of the invention may be
used for producing alcohol, such as ethanol, e.g., as an integral
part of a traditional ethanol process.
[0020] Fermentation Process
[0021] "Fermentation" or "fermentation process" refers to any
fermentation process or any process comprising a fermentation step.
A fermentation process of the invention includes, without
limitation, fermentation processes used to produce alcohols (e.g.,
ethanol, methanol, butanol); organic acids (e.g., citric acid,
acetic acid, itaconic acid, lactic acid, gluconic acid); ketones
(e.g., acetone); amino acids (e.g., glutamic acid); gases (e.g.,
H.sub.2 and CO.sub.2); antibiotics (e.g., penicillin and
tetracycline); enzymes; vitamins (e.g., riboflavin, B.sub.12,
beta-carotene); and hormones. Fermentation processes also include
fermentation processes used in the consumable alcohol industry
(e.g., beer and wine), dairy industry (e.g., fermented dairy
products), leather industry and tobacco industry. Preferred
fermentation processes include alcohol fermentation processes, as
are well known in the art. Preferred fermentation processes are
anaerobic fermentation processes, as are well known in the art.
[0022] In a preferred embodiment, the fermentation process of the
present invention is used in combination with a liquefaction
process and/or saccharification process, in which additional
enzymatic activities, such as esterase, such as lipase and/or
cutinase, phytase, laccase, cellulase, xylanase, alpha-amylase,
glucoamylase, or mixtures thereof, may be used in processing the
substrate, e.g., a starch substrate.
[0023] In yet another preferred embodiment, the fermentation
process is used in the production of ethanol. In a preferred
embodiment of the invention the fatty acid oxidizing enzyme is a
lipoxygenase.
[0024] Fermentation Media
[0025] "Fermentation media" or "fermentation medium" refers to the
environment in which the fermentation is carried out and which
includes the fermentation substrate, that is, the carbohydrate
source that is metabolized by the fermenting microorganism(s). The
fermentation media, including fermentation substrate and other raw
materials used in the fermentation process of the invention may be
processed, e.g., by milling, liquefaction and saccharification
processes or other desired processes prior to or simultaneously
with the fermentation process. Accordingly, the fermentation medium
can refer to the medium before the fermenting microorganism(s)
is(are) added, such as, the medium in or resulting from a
liquefaction and/or saccharification process, as well as the media
which comprises the fermenting microorganisms, such as, the media
used in a simultaneous saccharification and fermentation process
(SSF) or simultaneous liquefaction-saccharification-fermentation
(LSF) process.
[0026] Fermenting Organism
[0027] "Fermenting microorganism" refers to any microorganism
suitable for use in a desired fermentation process. Suitable
fermenting microorganisms according to the invention are able to
ferment, i.e., convert, sugars, such as glucose or maltose,
directly or indirectly into the desired fermentation product.
Examples of fermenting microorganisms include fungal organisms,
such as yeast. Preferred yeast includes strains of the Sacchromyces
spp., and in particular, Sacchromyces cerevisiae. Commercially
available yeast include, e.g., Red Star.quadrature./Lesaffre
Ethanol Red (available from Red Star/Lesaffre, USA) FALI (available
from Fleischmann's Yeast, a division of Burns Philp Food Inc.,
USA), SUPERSTART (available from Alltech), GERT STRAND (available
from Gert Strand AB, Sweden) and FERMIOL (available from DSM
Specialties).
[0028] Fermentation Substrate
[0029] Any suitable substrate or raw material may be used in a
fermentation process of the present invention. The substrate is
generally selected based on the desired fermentation product and
the process employed, as is well known in the art. Examples of
substrates suitable for use in the processes of present invention,
include starch-containing materials, such as tubers, roots, whole
grains, corns, cobs, wheat, barley, rye, milo or cereals,
sugar-containing whole grains, corns, cobs, wheat, barley, rye,
milo or cereals, sugar-containing raw materials, such as molasses,
fruit materials, sugar, cane or sugar beet, potatoes, and
cellulose-containing materials, such as wood or plant residues.
Suitable substrates also include carbohydrate sources, in
particular, low molecular sugars DP.sub.1-3 that can be metabolized
by the fermenting microorganism, and which may be supplied by
direct addition to the fermentation media.
[0030] Fatty Acid Oxidizing Enzyme
[0031] The term "a" fatty acid oxidizing enzyme means at least one
of such enzymes. The term "at least one" means one, two, three,
four, five, six or even more of such enzymes.
[0032] In the present context, a "fatty acid oxidizing enzyme" is
an enzyme which hydrolyzes the substrate linoleic acid more
efficiently than the substrate syringaldazine. "More efficiently"
means with a higher reaction rate. This can be tested using the
method described in Example 2, and calculating the difference
between (1) absorbancy increase per minute on the substrate
linoleic acid (absorbancy at 234 nm), and (2) absorbancy increase
per minute on the substrate syringaldazine (absorbancy at 530 nm),
i.e. by calculating the Reaction Rate Difference
(RRD)=(d(A.sub.234)/dt-d(A.sub.530)/dt). If the RRD is above zero,
the enzyme in question qualifies as a fatty acid oxidizing enzyme
as defined herein. If the RRD is zero, or below zero the enzyme in
question is not a fatty acid oxidizing enzyme.
[0033] In particular embodiments, the RRD is at least 0.05, 0.10,
0.15, 0.20, or at least 0.25 absorbancy units/minute.
[0034] In a particular embodiment of the method of Example 2, the
enzymes are well-defined. Still further, for the method of Example
2 the enzyme dosage is adjusted so as to obtain a maximum
absorbancy increase per minute at 234 nm, or at 530 nm. In
particular embodiments, the maximum absorbancy increase is within
the range of 0.05-0.50; 0.07-0.4; 0.08-0.3; 0.09-0.2; or 0.10-0.25
absorbancy units pr. min. The enzyme dosage may for example be in
the range of 0.01-20; 0.05-15; or 0.10-10 mg enzyme protein per
ml.
[0035] In the alternative, a "fatty acid oxidizing enzyme" may be
defined as an enzyme capable of oxidizing unsaturated fatty acids
more efficiently than syringaldazine. The activity of the enzyme
could be compared in a standard oximeter setup as described in
Example 1 of the present application at pH 6 and 30.theta.C
including either syringaldazine or linoleic acid as substrates.
[0036] In a particular embodiment, the fatty acid oxidizing enzyme
is defined as an enzyme classified as EC 1.11.1.3, or as EC
1.13.11.-. EC 1.13.11.- means any of the sub-classes thereof,
presently forty-nine: EC 1.13.11.1-EC 1.13.11.49. EC 1.11.1.3 is
designated fatty acid peroxidase, and EC 1.13.11.- is designated
oxygenases acting on single donors with incorporation of two atoms
of oxygen.
[0037] In a further particular embodiment, the EC 1.13.11.- enzyme
is classified as EC 1.13.11.12, EC 1.13.11.31, EC 1.13.11.33, EC
1.13.11.34, EC 1.13.11.40, EC 1.13.11.44 or EC 1.13.11.45,
designated lipoxygenase, arachidonate 12-lipoxygenase, arachidonate
15-lipoxygenase, arachidonate 5-lipoxygenase, arachidonate
8-lipoxygenase, linoleate diol synthase, and linoleate
11-lipoxygenase, respectively).
[0038] Examples of effective amounts of fatty acid oxidizing enzyme
are from 0.001 to 400 U/g DS (Dry Solids). Preferably, the fatty
acid oxidizing enzyme is used in an amount of 0.01 to 100 U/g DS,
more preferably 0.05 to 50 U/g DS, and even more preferably 0.1 to
20 U/g DS. Further optimization of the amount of fatty acid
oxidizing enzyme can hereafter be obtained using standard
procedures known in the art.
[0039] Lipoxygenase
[0040] In a preferred embodiment, the fatty acid oxidizing enzyme
is a lipoxygenase (LOX), classified as EC 1.13.11.12, which is an
enzyme that catalyzes the oxygenation of polyunsaturated fatty
acids, especially cis,cis-1,4-dienes, e.g. linoleic acid and
produces a hydroperoxide. But also other substrates may be
oxidized, e.g. monounsaturated fatty acids.
[0041] Microbial lipoxygenases can be derived from, e.g.,
Saccharomyces cerevisiae, Thermoactinomyces vulgaris, Fusarium
oxysporum, Fusarium proliferatum, Thermomyces lanuginosus,
Pyricularia oryzae, and strains of Geotrichum. The preparation of a
lipoxygenase derived from Gaeumannomyces graminis is described in
Examples 3-4 of WO 02/20730. The expression in Aspergillus oryzae
of a lipoxygenase derived from Magnaporthe salvinii is described in
Example 2 of WO 02/086114, and this enzyme can be purified using
standard methods, e.g. as described in Example 4 of WO
02/20730.
[0042] Lipoxygenase (LOX) may also be extracted from plant seeds,
such as soybean, pea, chickpea, and kidney bean. Alternatively,
lipoxygenase may be obtained from mammalian cells, e.g. rabbit
reticulocytes.
[0043] Lipoxygenase activity may be determined as described in the
"Materials and Methods" section.
[0044] Examples of effective amounts of lipoxygenase (LOX) are from
0.001 to 400 U/g DS (Dry Solids). Preferably, the lipoxygenase is
used in an amount of 0.01 to 100 U/g DS, more preferably 0.05 to 50
U/g DS, and even more preferably 0.1 to 20 U/g DS. Further
optimization of the amount of lipoxygenase can hereafter be
obtained using standard procedures known in the art.
[0045] Additional Enzymes
[0046] In a preferred embodiment of the invention one or more
additional enzyme activities may be used in combination with (such
as prior to, during or following) the fatty acid oxidizing enzyme
treatment of the present invention. Preferred additional enzymes
are esterases, such as lipases and/or cutinases, phytase, laccase,
proteases, cellulose, xylases, amylases, such as alpha-amylases,
maltogenic alpha-amylases, beta-amylases, or glucoamylases, or
mixtures thereof.
[0047] In another preferred embodiment of the present invention
stimulators for growth of the fermenting microorganism is(are)
added in combination with the enzymatic activities described
herein, to further improve the fermentation process. Preferred
stimulators for growth include vitamins and minerals.
[0048] Esterases
[0049] In a preferred embodiment of the invention the fatty acid
oxidizing enzyme is applied in an effective amount prior to or
during fermentation in combinations with an effective amount of
esterase. The enzymes may be added prior to or during fermentation,
including during or after the propogation of the fermenting
microorganisms. The enzymes may also be used to pre-treat the
fermentation medium (e.g., with or without addition of
backset).
[0050] As used herein, an "esterase" also referred to as a
carboxylic ester hydrolyases, refers to enzymes acting on ester
bonds, and includes enzymes classified in EC 3.1.1 Carboxylic Ester
Hydrolases according to Enzyme Nomenclature (available at
http://www.chem.qmw.ac.uk/iubmb/enzyme or from Enzyme Nomenclature
1992, Academic Press, San Diego, Calif., with Supplement 1 (1993),
Supplement 2 (1994), Supplement 3 (1995), Supplement 4 (1997) and
Supplement 5, in Eur. J. Biochem. 1994, 223, 1-5; Eur. J. Biochem.
1995, 232, 1-6; Eur. J. Biochem. 1996, 237, 1-5; Eur. J. Biochem.
1997, 250; 1-6, and Eur. J. Biochem. 1999, 264, 610-650;
respectively). Non-limiting examples of esterases include
arylesterase, triacylglycerol lipase, acetylesterase,
acetylcholinesterase, cholinesterase, tropinesterase,
pectinesterase, sterol esterase, chlorophyllase,
L-arabinonolactonase, gluconolactonase, uronolactonase, tannase,
retinyl-palmitate esterase, hydroxybutyrate-dimer hydrolase,
acylglycerol lipase, 3-oxoadipate enol-lactonase, 1,4-lactonase,
galactolipase, 4-pyridoxolactonase, acylcarnitine hydrolase,
aminoacyl-tRNA hydrolase, D-arabinonolactonase,
6-phosphogluconolactonase- , phospholipase A1,6-acetylglucose
deacetylase, lipoprotein lipase, dihydrocoumarin lipase,
limonin-D-ring-lactonase, steroid-lactonase, triacetate-lactonase,
actinomycin lactonase, orsellinate-depside hydrolase,
cephalosporin-C deacetylase, chlorogenate hydrolase,
alpha-amino-acid esterase, 4-methyloxaloacetate esterase,
carboxymethylenebutenolidase, deoxylimonate A-ring-lactonase,
2-acetyl-1-alkylglycerophosphocholine esterase, fusarinine-C
ornithinesterase, sinapine esterase, wax-ester hydrolase,
phorbol-diester hydrolase, phosphatidylinositol deacylase, sialate
O-acetylesterase, acetoxybutynylbithiophene deacetylase,
acetylsalicylate deacetylase, methylumbelliferyl-acetate
deacetylase, 2-pyrone-4,6-dicarboxylate lactonase,
N-acetylgalactosaminoglycan deacetylase, juvenile-hormone esterase,
bis(2-ethylhexyl)phthalate esterase, protein-glutamate
methylesterase, 11-cis-retinylpalmitate hydrolase,
all-trans-retinyl-palmitate hydrolase, L-rhamnono-1,4-lactonase,
5-(3,4-diacetoxybut-1-ynyl)-2,2'-bithiophene deacetylase,
fatty-acyl-ethyl-ester synthase, xylono-1,4-lactonase,
N-acetylglucosaminylphosphatidylinositol deacetylase, cetraxate
benzylesterase, acetylalkylglycerol acetylhydrolase, and
acetylxylan esterase.
[0051] Preferred esterases for use in the present invention are
lipolytic enzymes, such as, lipases (as classified by EC 3.1.1.3,
EC 3.1.1.23 and/or EC 3.1.1.26) and phospholipases (as classified
by EC 3.1.1.4 and/or EC 3.1.1.32, including lysophospholipases as
classified by EC 3.1.1.5). Other preferred esterases are cutinases
(as classified by EC 3.1.1.74).
[0052] When used in combination with processes or treatments which
employ other enzymes, beside the fatty acid oxidizing enzyme, such
as, phytase, laccase, amylases and glucoamylases used in, e.g.,
liquefaction and/or saccharification processes, esterase
compositions which do not inhibit these other enzymes are
preferred, e.g., esterases which do not contain or contain only
minor amounts of calcium-binding compounds are preferred.
Similarly, esterases which do not inhibit fermentation processes
are preferred, e.g., esterases which do not contain or which
contain only minor amounts of glycerol are preferred.
[0053] The esterase may be added in an amount effective to obtain
the desired benefit to improve the performance of the fermenting
microorganism, e.g., to change the lipid composition/concentration
inside and/or outside of the fermenting microorganism or in the
cell membrane of the fermenting microorganism, to result in an
improvement in the movement of solutes into and/or out of the
fermenting microorganisms during fermentation and/or to provide
more metabolizable energy sources (such as, e.g., by converting
components, such as, oil from the corn substrate, to components
useful the fermenting microorganism, e.g., unsaturated fatty acids
and glycerol), to increase ethanol yield. Examples of effective
amounts of esterase are from 0.01 to 400 LU/g DS (Dry Solids).
Preferably, the esterase is used in an amount of 0.1 to 100 LU/g
DS, more preferably 0.5 to 50 LU/g DS, and even more preferably 1
to 20 LU/g DS. Further optimization of the amount of esterase can
hereafter be obtained using standard procedures known in the
art.
[0054] In a preferred embodiment the esterase is a lipolytic
enzyme, more preferably, a lipase. As used herein, a "lipolytic
enzymes" refers to lipases and phospholipases (including
lysophospholipases). The lipolytic enzyme is preferably of
microbial origin, in particular of bacterial, fungal or yeast
origin. The lipolytic enzyme used may be derived from any source,
including, for example, a strain of Absidia, in particular Absidia
blakesleena and Absidia corymbifera, a strain of Achromobacter, in
particular Achromobacter iophagus, a strain of Aeromonas, a strain
of Alternaria, in particular Alternaria brassiciola, a strain of
Aspergillus, in particular Aspergillus niger and Aspergillus
flavus, a strain of Achromobacter, in particular Achromobacter
iophagus, a strain of Aureobasidium, in particular Aureobasidium
pullulans, a strain of Bacillus, in particular Bacillus pumilus,
Bacillus strearothermophilus and Bacillus subtilis, a strain of
Beauveria, a strain of Brochothrix, in particular Brochothrix
thermosohata, a strain of Candida, in particular Candida
cylindracea (Candida rugosa), Candida paralipolytica, and Candida
antarctica, a strain of Chromobacter, in particular Chromobacter
viscosum, a strain of Coprinus, in particular Coprinus cinerius, a
strain of Fusarium, in particular Fusarium oxysporum, Fusarium
solani, Fusarium solani pisi, and Fusarium roseum culmorum, a
strain of Geotricum, in particular Geotricum penicillatum, a strain
of Hansenula, in particular Hansenula anomala, a strain of
Humicola, in particular Humicola brevispora, Humicola brevis var.
thernoidea, and Humicola insolens, a strain of Hyphozyma, a strain
of Lactobacillus, in particular Lactobacillus curvatus, a strain of
Metarhizium, a strain of Mucor, a strain of Paecilomyces, a strain
of Penicillium, in particular Penicillium cyclopium, Penicillium
crustosum and Penicillium expansum, a strain of Pseudomonas in
particular Pseudomonas aeruginosa, Pseudomonas alcaligenes,
Pseudomonas cepacia (syn. Burkholderia cepacia), Pseudomonas
fluorescens, Pseudomonas fragi, Pseudomonas maltophilia,
Pseudomonas mendocina, Pseudomonas mephitica lipolytica,
Pseudomonas alcaligenes, Pseudomonas plantari, Pseudomonas
pseudoalcaligenes, Pseudomonas putida, Pseudomonas stutzeri, and
Pseudomonas wisconsinensis, a strain of Rhizoctonia, in particular
Rhizoctonia solani, a strain of Rhizomucor, in particular
Rhizomucor miehei, a strain of Rhizopus, in particular Rhizopus
japonicus, Rhizopus microsporus and Rhizopus nodosus, a strain of
Rhodosporidium, in particular Rhodosporidium toruloides, a strain
of Rhodotorula, in particular Rhodotorula glutinis, a strain of
Sporobolomyces, in particular Sporobolomyces shibatanus, a strain
of Thermomyces, in particular Thermomyces lanuginosus (formerly
Humicola lanuginosa), a strain of Thiarosporella, in particular
Thiarosporella phaseolina, a strain of Trichoderma, in particular
Trichoderma harzianum, and Trichoderma reesei, and/or a strain of
Verticillium.
[0055] In a preferred embodiment, the lipolytic enzyme is derived
from a strain of Aspergillus, a strain of Achromobacter, a strain
of Bacillus, a strain of Candida, a strain of Chromobacter, a
strain of Fusarium, a strain of Humicola, a strain of Hyphozyma, a
strain of Pseudomonas, a strain of Rhizomucor, a strain of
Rhizopus, or a strain of Thermomyces.
[0056] In more preferred embodiments, the lipolytic enzyme is a
lipase. Lipases may be applied herein for their ability to modify
the structure and composition of triglyceride oils and fats in the
fermentation media (including fermentation yeast), for example,
resulting from a corn substrate. Lipases catalyze different types
of triglyceride conversions, such as hydrolysis, esterification and
transesterification. Suitable lipases include acidic, neutral and
basic lipases, as are well-known in the art, although acidic
lipases (such as, e.g., the lipase G AMANO 50, available from
Amano) appear to be more effective at lower concentrations of
lipase as compared to either neutral or basic lipases. Preferred
lipases for use in the present invention included Candida
antarcitca lipase and Candida cylindracea lipase. More preferred
lipases are purified lipases such as Candida antarcitca lipase
(lipase A), Candida antarcitca lipase (lipase B), Candida
cylindracea lipase, and Penicillium camembertii lipase.
[0057] The lipase the one disclosed in EP 258,068-A or may be a
lipase variant such as a variant disclosed in WO 00/60063 or WO
00/32758 which is hereby incorporated by reference. Preferred
commercial lipases include LECITASE.TM., LIPOLASE.TM. and LIPEX.TM.
(available from Novozymes A/S, Denmark) and G AMANO 50 (available
from Amano).
[0058] Lipases are preferably added in amounts from about 1 to 400
LU/g DS, preferably 1 to 10 LU/g DS, and more preferably 1 to 5
LU/g DS.
[0059] In another preferred embodiment of the present invention,
the at least one esterase is a cutinase. Cutinases are enzymes
which are able to degrade cutin. The cutinase may be derived from
any source. In a preferred embodiment, the cutinase is derived from
a strain of Aspergillus, in particular Aspergillus oryzae, a strain
of Alternaria, in particular Alternaria brassiciola, a strain of
Fusarium, in particular Fusarium solani, Fusarium solani pisi,
Fusarium roseum culmorum, or Fusarium roseum sambucium, a strain of
Helminthosporum, in particular Helminthosporum sativum, a strain of
Humicola, in particular Humicola insolens, a strain of Pseudomonas,
in particular Pseudomonas mendocina, or Pseudomonas putida, a
strain of Rhizoctonia, in particular Rhizoctonia solani, a strain
of Streptomyces, in particular Streptomyces scabies, or a strain of
Ulocladium, in particular Ulocladium consortiale. In a most
preferred embodiment the cutinase is derived from a strain of
Humicola insolens, in particular the strain Humicola insolens DSM
1800. Humicola insolens cutinase is described in WO 96/13580 which
is herby incorporated by reference. The cutinase may be a variant
such as one of the variants disclosed in WO 00/34450 and WO
01/92502 which is hereby incorporated by reference. Preferred
cutinase variants include variants listed in Example 2 of WO
01/92502 which are hereby specifically incorporated by reference.
An effective amount of cutinase is between 0.01 and 400 LU/g DS,
preferably from about 0.1 to 100 LU/g DS, more preferably, 1 to 50
LU/g DS. Further optimization of the amount of cutinase can
hereafter be obtained using standard procedures known in the
art.
[0060] In another preferred embodiment, the at least one esterase
is a phospholipase. As used herein, the term phospholipase is an
enzyme which has activity towards phospholipids. Phospholipids,
such as lecithin or phosphatidylcholine, consist of glycerol
esterified with two fatty acids in an outer (sn-1) and the middle
(sn-2) positions and esterified with phosphoric acid in the third
position; the phosphoric acid, in turn, may be esterified to an
amino-alcohol. Phospholipases are enzymes which participate in the
hydrolysis of phospholipids. Several types of phospholipase
activity can be distinguished, including phospholipases A.sub.1 and
A.sub.2 which hydrolyze one fatty acyl group (in the sn-1 and sn-2
position, respectively) to form lysophospholipid; and
lysophospholipase (or phospholipase B) which can hydrolyze the
remaining fatty acyl group in lysophospholipid. Phospholipase C and
phospholipase D (phosphodiesterases) release diacyl glycerol or
phosphatidic acid respectively.
[0061] The term phospholipase includes enzymes with phospholipase
activity, e.g., phospholipase A (A.sub.1 or A.sub.2), phospholipase
B activity, phospholipase C activity or phospholipase D activity.
The term "phospholipase A" used herein in connection with an enzyme
of the invention is intended to cover an enzyme with Phospholipase
A.sub.1 and/or Phospholipase A.sub.2 activity. The phospholipase
activity may be provided by enzymes having other activities as
well, such as, e.g., a lipase with phospholipase activity. The
phospholipase activity may, e.g., be from a lipase with
phospholipase side activity. In other embodiments of the invention
the phospholipase enzyme activity is provided by an enzyme having
essentially only phospholipase activity and wherein the
phospholipase enzyme activity is not a side activity.
[0062] The phospholipase may be of any origin, e.g., of animal
origin (such as, e.g., mammalian), e.g. from pancreas (e.g. bovine
or porcine pancreas), or snake venom or bee venom. Alternatively,
the phospholipase may be of microbial origin, e.g. from filamentous
fungi, yeast or bacteria, such as the genus or species Aspergillus,
e.g., A. niger Dictyostelium, e.g. D. discoideum; Mucor, e.g. M.
javanicus, M. mucedo, M. subtilissimus; Neurospora, e.g. N. crassa;
Rhizomucor, e.g., R. pusillus; Rhizopus, e.g. R. arrhizus, R.
japonicus, R. stolonifer; Sclerotinia, e.g., S. libertiana;
Trichophyton, e.g. T. rubrum; Whetzelinia, e.g. W. sclerotiorum;
Bacillus, e.g., B. megaterium, B. subtilis; Citrobacter, e.g., C.
freundii; Enterobacter, e.g., E. aerogenes, E. cloacae
Edwardsiella, E. tarda; Erwinia, e.g., E. herbicola; Escherichia,
e.g., E. coli; Klebsiella, e.g., K. pneumoniae; Proteus, e.g., P.
vulgaris; Providencia, e.g. P. stuartii; Salmonella, e.g. S.
typhimurium; Serratia, e.g., S. liquefasciens, S. marcescens;
Shigella, e.g., S. flexneri; Streptomyces, e.g., S. violeceoruber,
Yersinia, e.g., Y. enterocolitica. Thus, the phospholipase may be
fungal, e.g., from the class Pyrenomycetes, such as the genus
Fusarium, such as a strain of F. culmorum, F. heterosporum, F.
solani, or a strain of F. oxysporum. The phospholipase may also be
from a filamentous fungus strain within the genus Aspergillus, such
as a strain of Aspergillus awamori, Aspergillus foetidus,
Aspergillus japonicus, Aspergillus niger or Aspergillus oryzae.
Preferred commercial phospholipases include LECITASE.TM. and
LECITASE.TM. ULTRA (available from Novozymes A/S, Denmark).
[0063] An effective amount of phosphorlipase is between 0.01 and
400 LU/g DS, preferably from about 0.1 to 100 LU/g DS, more
preferably, 1 to 50 LU/g DS. Further optimization of the amount of
phosphorlipase can hereafter be obtained using standard procedures
known in the art.
[0064] Phytase
[0065] In a preferred embodiment the fatty acid oxidizing enzyme is
used in combination with an effcient amount of phytase. In
accordance with this embodiment, a phytase may be used to promote
the liberation of inorganic phosphate from phytic acid
(myo-inositol hexakisphosphate) or from any salt thereof (phytates)
present in the medium.
[0066] Phytases can be classified according to their specificity in
the initial hydrolysis step, viz. according to which
phosphate-ester group is hydrolyzed first. The phytase to be used
may have any specificity, e.g., a 3-phytase (E.C. 3.1.3.8), a
6-phytase (E.C. 3.1.3.26) or a 5-phytase (no E.C. number).
[0067] The phytase may be added during the fermentation or prior to
fermentation, such as, during propogation or in a step prior to
fermentation, e.g., a liquefaction and/or saccharification step.
The phytases may be added, e.g., to improve the bioavailability of
essential minerals to yeast, as described in WO 01/62947, which is
hereby incorporated by reference. The phytase may also be used to
pre-treat the fermentation medium (e.g., with or without
backset).
[0068] The phytase may be derived from plants or microorganisms,
such as bacteria or fungi, e.g., yeast or filamentous fungi. The
plant phytase may be from wheat-bran, maize, soy bean or lily
pollen. Suitable plant phytases are described in Thomlinson et al,
Biochemistry, 1 (1962), 166-171; Barrientos et al, Plant. Physiol.,
106 (1994),1489-1495; WO 98/05785; WO 98/20139.
[0069] A bacterial phytase may be from genus Bacillus, Pseudomonas
or Escherichia, preferably the species B. subtilis or E. coli.
Suitable bacterial phytases are described in Paver and Jagannathan,
1982, Journal of Bacteriology 151:1102-1108; Cosgrove, 1970,
Australian Journal of Biological Sciences 23:1207-1220; Greiner et
al, Arch. Biochem. Biophys., 303, 107-113, 1993; WO 98/06856; WO
97/33976; WO 97/48812.
[0070] A yeast phytase or myo-inositol monophosphatase may be
derived from genus Saccharomyces or Schwanniomyces, preferably
species Saccharomyces cerevisiae or Schwanniomyces occidentalis.
Suitable yeast phytases are described in Nayini et al, 1984,
Lebensmittel Wissenschaft und Technologie 17:24-26; Wodzinski et
al, Adv. Appl. Microbiol., 42, 263-303; AU-A-24840/95;
[0071] Phytases from filamentous fungi may be derived from the
fungal phylum of Ascomycota (ascomycetes) or the phylum
Basidiomycota, e.g., the genus Aspergillus, Thermomyces (also
called Humicola), Myceliophthora, Manascus, Penicillium,
Peniophora, Agrocybe, Paxillus, or Trametes, preferably the species
Aspergillus terreus, Aspergillus niger, Aspergillus niger var.
awamori, Aspergillus ficuum, Aspergillus fumigatus, Aspergillus
oryzae, T. lanuginosus (also known as H. lanuginosa),
Myceliophthora thermophila, Peniophora lycii, Agrocybe pediades,
Manascus anka, Paxillus involtus, or Trametes pubescens. Suitable
fungal phytases are described in Yamada et al., 1986, Agric. Biol.
Chem. 322:1275-1282; Piddington et al., 1993, Gene 133:55-62; EP
684,313; EP 0 420 358; EP 0 684 313; WO 98/28408; WO 98/28409; JP
7-67635; WO 98/44125; WO 97/38096; WO 98/13480 in corpporated by
reference.
[0072] Modified phytases or phytase variants are obtainable by
methods known in the art, in particular by the methods disclosed in
EP 897,010; EP 897,985; WO 99/49022; WO 99/48330. Commercially
available phytases include BIO-FEED PHYTASE.TM., PHYTASE NOVO.TM.
CT or L (Novozymes A/S, Denmark), or NATUPHOS.TM. NG 5000
(DSM).
[0073] The phytase may preferably be added in the range
5,000-250,000 FYT/g DS, preferably 10,000-100,000 FYT/g DS. A
preferred suitable dosage of the phytase is in the range from
0.005-25 FYT/g DS, more preferably 0.01-10 FYT/g, such as 0.1-1
FYT/g DS. Here, the phytase activity is determined using FYT units,
one FYT being the amount of enzyme that liberates 1 micromole
inorganic ortho-phosphate per min. under the following conditions:
pH 5.5; temperature 37.degree. C.; substrate: sodium phytate
(C.sub.6H.sub.6O.sub.24P.sub.6Na.sub.12) at a concentration of
0.0050 mole/I.
[0074] Proteases
[0075] In another preferred embodiment, the fatty acid oxidizing
enzyme treatment is used in combination with at least one protease.
The protease may be used, e.g., to digest protein to produce free
amino nitrogen (FAN). Such free amino acids function as nutrients
for the yeast, thereby enhancing the growth of the yeast and,
consequently, the production of ethanol.
[0076] The fermenting microorganism for use in a fermentation
process may be produced by propagating the fermenting microorganism
in the presence of at least one protease. Although not limited to
any one theory of operation, it is believed that the propogation of
the fermenting microorganism with an effective amount of at least
one protease reduces the lag time of the fermenting microorganism
when the fermenting microorganism is subsequently used in a
fermentation process as compared to a fermenting microorganism that
was propogated under the same conditions without the addition of
the protease. The action of the protease in the propogation process
is believed to directly or indirectly result in the suppression or
expression of genes which are detrimental or beneficial,
respectively, to the fermenting microorganism during fermentation,
thereby decreasing lag time and resulting in a faster fermentation
cycle.
[0077] Proteases are well known in the art and refer to enzymes
that catalyze the cleavage of peptide bonds. Suitable proteases
include fungal and bacterial proteases. Preferred proteases are
acidic proteases, i.e., proteases characterized by the ability to
hydrolyze proteins under acidic conditions below pH 7. Suitable
acid fungal proteases include fungal proteases derived from
Aspergillus, Mucor, Rhizopus, Candida, Coriolus, Endothia,
Enthomophtra, Irpex, Penicillium, Sclerotium and Torulopsis.
Especially contemplated are proteases derived from Aspergillus
niger (see, e.g., Koaze et al., (1964), Agr. Biol. Chem. Japan, 28,
216), Aspergillus saitoi (see, e.g., Yoshida, (1954) J. Agr. Chem.
Soc. Japan, 28, 66), Aspergillus awamori (Hayashida et al., (1977)
Agric. Biol. Chem., 42(5), 927-933, Aspergillus aculeatus (WO
95/02044), or Aspergillus oryzae; and acidic proteases from Mucor
pusillus or Mucor miehei.
[0078] Bacterial proteases, which are not acidic proteases, include
the commercially available products ALCALASE.TM. and NEUTRASE.TM.
(available from Novozymes A/S). Other proteases include GC106 from
Genencor Int, Inc., USA and NOVOZYM.TM. 50006 from Novozymes A/S,
Denmark.
[0079] Preferably, the protease is an aspartic acid protease, as
described, for example, Handbook of Proteolytic Enzymes, Edited by
A. J. Barrett, N. D. Rawlings and J. F. Woessner, Academic Press,
San Diego, 1998, Chapter 270). Suitable examples of aspartic acid
protease include, e.g., those disclosed in R. M. Berka et al. Gene,
96, 313 (1990)); (R. M. Berka et al. Gene, 125, 195-198 (1993));
and Gomi et al. Biosci. Biotech. Biochem. 57, 1095-1100 (1993),
which are hereby incorporated by reference.
[0080] Laccase
[0081] In another preferred embodiment, the fatty acid oxidizing
enzyme treatment is used in combination with laccase. The laccase
is applied in an effective amount during fermentation and/or the
laccase is applied in an effective amount before or during
fermentation, such as, during the propagation of the fermenting
microorganisms. Although not limited to any one theory of
operation, it is believed that the use of at least one laccase in
the fermentation process promotes the oxidation of inhibitors and
oxygen depletion, so as to promote the creation of an anaerobic
environment more suitable to the fermenting microorganism.
[0082] In the context of this invention, laccases and laccase
related enzymes comprise any laccase enzyme comprised by the enzyme
classification (EC 1.10.3.2), any catechol oxidase enzyme comprised
by the enzyme classification (EC 1.10.3.1), any bilirubin oxidase
enzyme comprised by the enzyme classification (EC 1.3.3.5) or any
monophenol monooxygenase enzyme comprised by the enzyme
classification (EC 1.14.18.1).
[0083] The above mentioned enzymes may be derived from plants,
bacteria or fungi (including filamentous fungi and yeasts) and
suitable examples include a laccase derived from a strain of
Aspergillus, Neurospora, e.g., N. crassa, Podospora, Botrytis,
Collybia, Fomes, Lentinus, Pleurotus, Trametes, e.g., T. villosa
and T. versicolor, Rhizoctonia, e.g., R. solani, Coprinus, e.g., C.
cinereus, C. comatus, C. friesii, and C. plicatilis, Psathyrella,
e.g., P. condelleana, Panaeolus, e.g. P. papilionaceus,
Myceliophthora, e.g., M. thermophila, Schytalidium, e.g., S.
thermophilum, Polyporus, e.g., P. pinsitus, Pycnoporus, e.g., P.
cinnabarinus, Phlebia, e.g., P. radita (WO 92/01046), or Coriolus,
e.g., C. hirsutus (JP 2-238885).
[0084] A laccase derived from Coprinus, Myceliophthora, Polyporus,
Pycnoporus, Scytalidium or Rhizoctonia is preferred, in particular
a laccase derived from Coprinus cinereus, Myceliophthora
thermophila, Polyporus pinsitus, Pycnoporus cinnabarinus,
Scytalidium thermophilum or Rhizoctonia solani.
[0085] Amylase
[0086] In yet another preferred embodiment, the fatty acid
oxidizing enzyme treatment is used in combination with an amylase.
Preferred are alpha-amylases of fungal or bacterial origin.
[0087] More preferably, the alpha-amylase is a Bacillus
alpha-amylases, such as, derived from a strain of B. licheniformis,
B. amyloliquefaciens, and B. stearothermophilus. Other
alpha-amylases include alpha-amylase derived from a strain of the
Bacillus sp. NCIB 12289, NCIB 12512, NCIB 12513 or DSM 9375, all of
which are described in detail in WO 95/26397, and the alpha-amylase
described by Tsukamoto et al., Biochemical and Biophysical Research
Communications, 151 (1988), pp. 25-31. Other alpha-amylase variants
and hybrids are described in WO 96/23874, WO 97/41213, and WO
99/19467. Other alpha-amylase includes alpha-amylases derived from
a strain of Aspergillus, such as, Aspergillus oryzae and
Aspergillus niger alpha-amylases. In a preferred embodiment, the
alpha-amylase is a acid alpha-amylase. In a more preferred
embodiment the acid alpha-amylase is an acid fungal alpha-amylase
or an acid bacterial alpha-amylase. More preferably, the acid
alpha-amylase is an acid fungal alpha-amylase derived from the
genus Aspergillus. A commercially available acid fungal amylase is
SP288 (available from Novozymes A/S, Denmark).
[0088] In a preferred embodiment, the alpha-amylase is an acid
alpha-amylase. The term "acid alpha-amylase" means an alpha-amylase
(E.C. 3.2.1.1) which added in an effective amount has activity at a
pH in the range of 3.0 to 7.0, preferably from 3.5 to 6.0, or more
preferably from 4.0-5.0.
[0089] A preferred acid fungal alpha-amylase is a Fungamyl-like
alpha-amylase. In the present disclosure, the term "Fungamyl-like
alpha-amylase" indicates an alpha-amylase which exhibits a high
homology, i.e. more than 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or
even 90% homology to the amino acid sequence shown in SEQ ID No. 10
in WO96/23874. When used as a maltose generating enzyme fungal
alpha-amylases may be added in an amount of 0.001-1.0 AFAU/g DS,
preferably from 0.002-0.5 AFAU/g DS, preferably 0.02-0.1 AFAU/g
DS.
[0090] Preferably the alpha-amylase is an acid alpha-amylase,
preferably from the genus Aspergillus, preferably of the species
Aspergillus niger. In a preferred embodiment the acid fungal
alpha-amylase is the one from A. niger disclosed as "AMYA_ASPNG" in
the Swissprot/TeEMBL database under the primary accession no.
P56271. Also variant of set acid fungal amylase having at least 70%
homology, such as at least 80% or even at least 90% homology
thereto is contemplated.
[0091] A preferred acid alpha-amylase for use in the present
invention may be derived from a strain of B. licheniformis, B.
amyloliquefaciens, and B. stearothermophilus.
[0092] Preferred commercial compositions comprising alpha-amylase
include MYCOLASE from DSM (Gist Brochades), BAN.TM., TERMAMYLTM SC,
FUNGAMYL.TM., LIQUOZYMETM X and SAN.TM. SUPER, SAN.TM. EXTRA L
(Novozymes A/S) and CLARASE.TM. L-40,000, DEX-LO.TM., SPEYME FRED,
SPEZYME.TM., and SPEZYME.TM. DELTA M (Genencor Int.), and the acid
fungal alpha-amylase sold under the trade name SP 288 (available
from Novozymes A/S, Denmark).
[0093] The amylase may also be a maltogenic alpha-amylase. A
"maltogenic alpha-amylase" (glucan 1,4-alpha-maltohydrolase, E.C.
3.2.1.133) is able to hydrolyze amylose and amylopectin to maltose
in the alpha-configuration. A maltogenic alpha-amylase from B.
stearothermophilus strain NCIB 11837 is commercially available from
Novozymes A/S under the tradename NOVAMYL.TM.. Maltogenic
alpha-amylases are described in U.S. Pat. Nos. 4,598,048, 4,604,355
and 6,162,628, which are hereby incorporated by reference.
Preferably, the maltogenic alpha-amylase is used in a raw starch
hydrolysis process, as described, e.g., in WO 95/10627, which is
hereby incorporated by reference.
[0094] The alpha-amylase may be added in amounts as are well-known
in the art. When measured in AAU units the acid alpha-amylase
activity is preferably present in an amount of 5-50,0000 MU/kg of
DS, in an amount of 500-50,000 MU/kg of DS, or more preferably in
an amount of 100-10,000 MU/kg of DS, such as 500-1,000 MU/kg DS.
Fungal acid alpha-amylase are preferably added in an amount of
10-10,000 AFAU/kg of DS, in an amount of 500-2,500 AFAU/kg of DS,
or more preferably in an amount of 100-1,000 AFAU/kg of DS, such as
approximately 500 AFAU/kg DS.
[0095] The glucoamylase used according to an embodiment of the
process of the invention may be derived from any suitable source,
e.g., derived from a microorganism or a plant. Preferred
glucoamylases are of fungal or bacterial origin, selected from the
group consisting of Aspergillus glucoamylases, in particular A.
niger G1 or G2 glucoamylase (Boel et al. (1984), EMBO J. 3 (5), p.
1097-1102), or variants thereof, such as disclosed in WO 92/00381
and WO 00/04136; the A. awamori glucoamylase (WO 84/02921), A.
oryzae (Agric. Biol. Chem. (1991), 55 (4), p. 941-949), or variants
or fragments thereof.
[0096] Other Aspergillus glucoamylase variants include variants to
enhance the thermal stability: G137A and G139A (Chen et al. (1996),
Prot. Engng. 9, 499-505); D257E and D293E/Q (Chen et al. (1995),
Prot Engng. 8, 575-582); N182 (Chen et al. (1994), Biochem. J. 301,
275-281); disulphide bonds, A246C (Fierobe et al. (1996),
Biochemistry, 35, 8698-8704; and introduction of Pro residues in
position A435 and S436 (Li et al. (1997), Protein Engng. 10,
1199-1204. Other glucoamylases include Talaromyces glucoamylases,
in particular, derived from Talaromyces emersonii (WO 99/28448),
Talaromyces leycettanus (U.S. Pat. No. Re. 32,153), Talaromyces
duponti, Talaromyces thermophilus (U.S. Pat. No. 4,587,215).
Bacterial glucoamylases contemplated include glucoamylases from the
genus Clostridium, in particular C. thermoamylolyticum (EP
135,138), and C. thermohydrosulfuricum (WO 86/01831).
[0097] Commercially available compositions comprising glucoamylase
include AMG 200L; AMG 300 L; SAN.TM. SUPER, SAN.TM. EXTRA L,
SPIRIZYME.TM. PLUS, SPIRIZYME.TM. FUEL and AMG.TM. E (from
Novozymes A/S); OPTIDEX.TM. 300 (from Genencor Int.); AMIGASE.TM.
and AMIGASE.TM. PLUS (from DSM); G-ZYME.TM. G900, G-ZYME.TM. and
G990 ZR (from Genencor Int.).
[0098] Glucoamylases may in an embodiment be added in an amount of
0.02-20 AGU/g DS, preferably 0.1-10 AGU/g DS, such as 2 AGU/g
DS.
[0099] Xylanase
[0100] In another preferred embodiment, the fatty acid oxidizing
enzyme treatment is used in combination with a xylanase. The
xylanase (E.C. 3.2.1.8) activity may be derived from any suitable
source, including fungal and bacterial organisms, such as
Aspergillus, Disporotrichum, Penicillium, Neurospora, Fusarium and
Trichoderma. Preferred commercially available preparations
comprising xylanase include SHEARZYME.RTM., BIOFEED WHEAT.RTM.,
CELLUCLAST.RTM., ULTRAFLO.RTM., VISCOZYME.RTM. (Novozymes A/S) and
SPEZYME.RTM. CP (Genencor Int.).
[0101] Cellulase
[0102] In yet another preferred, the fatty acid oxidizing enzyme
treatment is used in combination with a cellulase. The cellulase
activity used according to the invention may be derived from any
suitable origin, preferably, the cellulase is of microbial origin,
such as derivable from a strain of a filamentous fungus (e.g.,
Aspergillus, Trichoderma, Humicola, Fusarium). Commercially
available preparations comprising cellulase which may be used
include CELLUCLAST.TM., CELLUZYME.TM., CEREFLO.TM. and ULTRAFLO.TM.
(Novozymes A/S), LAMINEX.TM. and SPEZYME.TM. CP (Genencor Int.) and
ROHAMENT.TM. 7069 W (from Rohm GmbH).
[0103] Production of Enzymes
[0104] The fatty acid oxidizing enzyme and other enzymes referenced
herein may be derived or obtained from any suitable origin,
including, bacterial, fungal, yeast or mammalian origin. The term
"derived" or means in this context that the enzyme may have been
isolated from an organism where it is present natively, i.e., the
identity of the amino acid sequence of the enzyme are identical to
a native enzyme. The term "derived" also means that the enzymes may
have been produced recombinantly in a host organism, the
recombinant produced enzyme having either an identity identical to
a native enzyme or having a modified amino acid sequence, e.g.
having one or more amino acids which are deleted, inserted and/or
substituted, i.e., a recombinantly produced enzyme which is a
mutant and/or a fragment of a native amino acid sequence or an
enzyme produced by nucleic acid shuffling processes known in the
art. Within the meaning of a native enzyme are included natural
variants. Furthermore, the term "derived" includes enzymes produced
synthetically by, e.g., peptide synthesis. The term "derived" also
encompasses enzymes which have been modified e.g. by glycosylation,
phosphorylation, or by other chemical modification, whether in vivo
or in vitro. The term "obtained" in this context means that the
enzyme has an amino acid sequence identical to a native enzyme. The
term encompasses an enzyme that has been isolated from an organism
where it is present natively, or one in which it has been expressed
recombinantly in the same type of organism or another, or enzymes
produced synthetically by, e.g., peptide synthesis. With respect to
recombinantly produced enzymes the terms "obtained" and "derived"
refers to the identity of the enzyme and not the identity of the
host organism in which it is produced recombinantly.
[0105] The enzymes may also be purified. The term "purified" as
used herein covers enzymes free from other components from the
organism from which it is derived. The term "purified" also covers
enzymes free from components from the native organism from which it
is obtained. The enzymes may be purified, with only minor amounts
of other proteins being present. The expression "other proteins"
relate in particular to other enzymes. The term "purified" as used
herein also refers to removal of other components, particularly
other proteins and most particularly other enzymes present in the
cell of origin of the enzyme of the invention. The enzyme may be
"substantially pure," that is, free from other components from the
organism in which it is produced, that is, for example, a host
organism for recombinantly produced enzymes. In preferred
embodiment, the enzymes are at least 75% (w/w) pure, more
preferably at least 80%, at least 85%, at least 90%, at least 95%,
at least 96%, at least 97%, at least 98%, or at least 99% pure. In
another preferred embodiment, the enzyme is 100% pure.
[0106] The enzymes used in the present invention may be in any form
suitable for use in the processes described herein, such as, e.g.,
in the form of a dry powder or granulate, a non-dusting granulate,
a liquid, a stabilized liquid, or a protected enzyme. Granulates
may be produced, e.g., as disclosed in U.S. Pat. Nos. 4,106,991 and
U.S. Pat. No. 4,661,452, and may optionally be coated by process
known in the art. Liquid enzyme preparations may, for instance, be
stabilized by adding stabilizers such as a sugar, a sugar alcohol
or another polyol, lactic acid or another organic acid according to
established process. Protected enzymes may be prepared according to
the process disclosed in EP 238,216.
[0107] Fermentation Stimulators
[0108] In accordance with another preferred embodiment, a
fermentation stimulator may be used in combination with any of the
enzymatic processes described herein to further improve the
fermentation process, and in particular, the performance of the
fermenting microorganism, such as, rate enhancement and ethanol
yield. A "fermentation stimulator" refers to stimulators for growth
of the fermenting microorganisms, in particular, yeast. Preferred
fermentation stimulators for growth include vitamins and minerals.
Examples of vitamins include multivitamins, biotin, pantothenate,
nicotinic acid, meso-inositol, thiamine, pyridoxine,
para-aminobenzoic acid, folic acid, riboflavin, and Vitamins A, B,
C, D, and E. See, e.g., Alfenore et al., Improving ethanol
production and viability of Saccharomyces cerevisia by a vitamin
feeding strategy during fed-batch process," Springer-Verlag (2002),
which is hereby incorporated by reference. Examples of minerals
include minerals and mineral salts that can supply nutrients
comprising P, K, Mg, S, Ca, Fe, Zn, Mn, and Cu.
[0109] Liquefaction or Saccharification
[0110] Any liquefaction or saccharification may be used in
combination with the fermentation process of the present invention.
According to the present invention the saccharification and
liquefaction may be carried out simultaneously or separately with
the fermentation process. In a preferred embodiment of the present
invention, the liquefaction, saccharification and fermentation
processes are carried out simultaneously (LSF).
[0111] "Liquefaction" is a process in which milled (whole) grain
raw material is broken down (hydrolyzed) into maltodextrins
(dextrins). Liquefaction is often carried out as a three-step hot
slurry process. The slurry is heated to between 60-95.degree. C.,
preferably 80-85.degree. C., and the enzymes are added to initiate
liquefaction (thinning). The slurry is then jet-cooked at a
temperature between 95-140.degree. C., preferably 105-125.degree.
C. to complete gelanitization of the slurry. Then the slurry is
cooled to 60-95.degree. C. and more enzyme(s) is(are) added to
finalize hydrolysis (secondary liquefaction). The liquefaction
process is usually carried out at pH 4.5-6.5, in particular at a pH
between 5 and 6. Milled and liquefied whole grains are known as
mash.
[0112] The liquefaction processes are typically carried out using
any of the alpha-amylase listed above I the "Amylase" section.
[0113] "Saccharification" is a process in which the maltodextrin
(such as, produced from the liquefaction process) is converted to
low molecular sugars DP.sub.1-3 (i.e., carbohydrate source) that
can be metabolized by the fermenting organism, such as, yeast.
Saccharification processes are well known in the art and are
typically performed enzymatically using a glucoamylase.
Alternatively or in addition, alpha-glucosidases or acid
alpha-amylases may be used. A full saccharification process may
last up to from about 24 to about 72 hours, and is often carried
out at temperatures from about 30 to 65.degree. C., and at a pH
between 4 and 5, normally at about pH 4.5. However, it is often
more preferred to do a pre-saccharification step, lasting for about
40 to 90 minutes, at temperature of between 30-65.degree. C.,
typically about 60.degree. C., followed by complete
saccharification during fermentation in a simultaneous
saccharification and fermentation process (SSF).
[0114] The most widely used process in ethanol production is the
simultaneous saccharification and fermentation (SSF) process, in
which there is no holding stage for the saccharification, meaning
that fermenting organism, such as the yeast, and enzyme(s) is(are)
added together. In SSF processes, it is common to introduce a
pre-saccharification step at a temperature above 50.degree. C.,
just prior to the fermentation.
[0115] More preferably, the liquefaction, saccharification or
fermentation process is a simultaneous
liquefaction-saccharification-fermentation (LSF) process or single
enzymatic process, in which the liquefaction, saccharification and
fermentation process are all carried out in one process, that is,
all enzymes (or substitutable or additional non-enzymatic agents)
used for liquefaction, saccharification and fermentation are added
in the same process step, more preferably, simultaneously in the
same process step. Preferred process conditions for LSF process
include temperatures of about 26.degree. C. to 40.degree. C.,
preferably about 32.degree. C., pH of about 4 to about 8,
preferably about pH 5, and process times of about 48 to 72 hours,
preferably about 72 hours.
[0116] Preferably, the LSF process or single enzymatic process is a
raw starch hydrolysis (RSH) processes, more preferably, used in the
production of alcohol, such as, e.g., ethanol. A "raw starch
hydrolysis" process (RSH) differs from conventional starch
treatment processes in that raw uncooked starch, also referred to
as granular starch, is used in the ethanol fermentation process. As
used herein, the term "granular starch" means raw uncooked starch,
i.e. starch in its natural form found in cereal, tubers or grains.
Starch is formed within plant cells as tiny granules insoluble in
water. When put in cold water, the starch granules may absorb a
small amount of the liquid and swell. At temperatures up to
50.degree. C. to 75.degree. C. the swelling may be reversible.
However, with higher temperatures an irreversible swelling called
gelatinization begins.
[0117] The term "initial gelatinization temperature" means the
lowest temperature at which gelatinization of the starch commences.
Starch heated in water begins to gelatinize between 50.degree. C.
and 75.degree. C.; the exact temperature of gelatinization depends
on the specific starch, and can readily be determined by the
skilled artisan. Thus, the initial gelatinization temperature may
vary .alpha.-cording to the plant species, to the particular
variety of the plant species as well as with the growth conditions.
In the context of this invention the initial gelatinization
temperature of a given starch is the temperature at which
birefringence is lost in 5% of the starch granules using the
process described by Gorinstein. S. and Lii. C., Starch/Starke,
Vol. 44 (12) pp. 461-466 (1992).
[0118] In accordance with a preferred embodiment, fatty acid
oxidizing enzyme can be used, preferably in combination with
esterases, a phytase, laccase, protease, amylases and/or a
glucoamylases, to increase ethanol yield in raw starch hydrolysis
processes.
[0119] In a preferred embodiment, the present invention involves
treating granular starch slurry with a fatty acid oxidizing enzyme
and one or more of activity from the group of phytase, esterase,
protease, laccase, glucoamylase and/or (maltogenic) alpha-amylase,
yeast at a temperature below the initial gelatinizatiion
temperature of granular starch. Preferably, the yeast is Ethanol
Red yeast. The amylase is preferably an acid alpha-amylase, more
preferably an acid fungal alpha-amylase.
[0120] In a more preferred embodiment, the raw starch hydrolysis
process entails, treating granular starch slurry with a
glucoamylase and/or alpha-amylase at a temperature between
0.degree. C. and 20.degree. C. below the initial gelatinization
temperature of the granular starch, followed by treating the slurry
with a glucoamylase and/or alpha amylase, yeast and at least one
fatty acid oxidazing enzyme, and optionally an esterase, protease,
phytase, laccase, amylase and/or glucoamylase at a temperature of
between 10.degree. C. and 35.degree. C.
[0121] In yet another preferred embodiment, the process entails the
sequential steps of: (a) treating a granular starch slurry with an
acid alpha-amylase and a glucoamylase at a temperature of 0.degree.
C. to 20.degree. C. below the initial gelatinization temperature of
the granular starch, preferably for a period of 5 minutes to 12
hours, (b) treating the slurry in the presence of an acid
alpha-amylase, a glucoamylase, a yeast and at least one fatty acid
oxidizing enzyme, and optionally a phytase, protease, laccase,
esterase at a temperature of between 10.degree. C. and 35.degree.
C., preferably for a period of 20 to 250 hours to produce
ethanol.
[0122] Other enzymes and fermentation stimulators may be used in
combination with the fatty acid oxidizing enzyme treatment in the
RSH process. Preferably, the other enzyme is selected from the
group consisting of an esterase, such as lipase, or cutinase,
phytase, protease, cellulase, xylanase, alpha-amylase, such as a
maltogenic alpha-amylase, glucoamylase and combinations thereof. In
RSH processes, phytic acid is present in significant amounts.
Accordingly, in a preferred embodiment, phytases can be used to
promote the liberation of inorganic phosphate from phytic acid
(myo-inositol hexakisphosphate) or from any salt thereof
(phytates), as previously described.
[0123] In another preferred embodiment, a maltogenic alpha-amylase
is used in combination with the fatty acid oxidizing enzyme
treatment in the RSH process.
[0124] A preferred application of the fermentation processes and
compositions described herein is in an alcohol production process
(such as, e.g., ethanol for use as a fuel or fuel additive), more
preferably using a raw starch hydrolysis process. The processes
described herein can be used, e.g., to increase the rate and/or
yield of ethanol production. The addition of an effective amount of
at least one fatty acid oxidizing enzyme can be used to improve
ethanol yield of the fermentation product.
[0125] Ethanol production processes generally involve the steps of
milling, liquefaction, saccharification, fermentation and
distillation. In the production of ethanol and other starch-based
products, the raw material, such as whole grain, preferably corn,
is milled in order to open up the structure and allow for further
processing. Two processes are preferred according to the invention:
wet milling and dry milling. Preferred for ethanol production is
dry milling where the whole kernel is milled and used in the
remaining part of the process. Wet milling may also be used and
gives a good separation of germ and meal (starch granules and
protein) and is with a few exceptions applied at locations where
there is a parallel production of syrups. Both wet and dry milling
processes are well known in the art.
[0126] In ethanol production, the fermenting organism is preferably
yeast, which is applied to the mash. Preferred yeast is derived
from Saccharomyces spp., more preferably, from Saccharomyces
cerevisiae. In preferred embodiments, yeast is applied to the mash
and the fermentation is ongoing for 24-96 hours, such as typically
35-60 hours. In preferred embodiments, the temperature is generally
between 26-34.degree. C., in particular about 32.degree. C., and
the pH is generally from pH 3-6, preferably around pH 4-5. Yeast
cells are preferably applied in amounts of 10.sup.5 to 10.sup.12,
preferably from 10.sup.7 to 10.sup.10, especially 5.times.10.sup.7
viable yeast count per ml of fermentation broth. During the ethanol
producing phase the yeast cell count should preferably be in the
range from 10.sup.7 to 10.sup.10, especially around
2.times.10.sup.8. Further guidance in respect of using yeast for
fermentation can be found in, e.g., "The alcohol Textbook" (Editors
K. Jacques, T. P. Lyons and D. R. Kelsall, Nottingham University
Press, United Kingdom 1999), which is hereby incorporated by
reference.
[0127] Following fermentation, the mash may be distilled to extract
the alcohol product (ethanol). In the case where the end product is
ethanol, obtained according to the processes of the invention, it
may be used as, e.g., fuel ethanol; drinking ethanol, i.e., potable
neutral spirits; or industrial ethanol.
[0128] In an aspect the invention relates to a process for
producing ethanol, comprising
[0129] (a) milling whole grains;
[0130] (b) liquefying the product of step (a);
[0131] (c) saccharifying the liquefied material;
[0132] (d) fermenting the saccharified material using a
microorganism, wherein the fermentation process further comprises
contacting the fermentation media with at least one fatty acid
oxidizing enzyme.
[0133] The fatty acid oxidizing enzyme and additional enzymes and
stimulators may be any of the above mentioned. The preferred fatty
acid oxidizing enzyme is lipoxygenase.
[0134] In a final aspect the invention relates to a composition
comprising a fatty acid oxidizing enzyme and one or more enzymes
selected from the group consisting of an esterase, phytase,
laccase, protease, cellulase, xylanase, amylase, such as
alpha-amylase or glycoamylase, or mixtures thereof. In a preferred
embodiment the fatty acid oxidizing enzymes is a lipoxygenase
(LOX), preferably any of the one mentioned above. In an embodiment
the composition further comprises a lipase, and optionally an
alpha-amylase and/or glucoamylase.
[0135] Materials and Methods
[0136] Fatty acid oxidizing enzyme: Lipoxygenase derived from
Magnaporthe salvinii, disclosed in WO 02/086114 (available from
Novozymes A/S, Denmark).
[0137] Lipase: LIPOLASE.TM. 100 L (availablke from Novozymes A/S,
Denmark)
[0138] Glucoamylase: SPIRIZYME FUEL (available from Novozymes
A/S)
[0139] Protease: NOVOZYM.TM. 50006 available from Novozymes A/S,
Denmark)
[0140] Yeast: Ethanol Red available from Red Star/Lesaffre, USA
[0141] Methods:
[0142] Preparation of Backset:
[0143] Centrate after centrifugation of fermented raw starch from a
beer stripper column
[0144] Lipoxygenase Activity
[0145] Lipoxygenase activity may be determined
spectrophotometrically at 25.theta.C by monitoring the formation of
hydroperoxides. For the standard analysis, 10 micro liters enzyme
is added to a 1 ml quartz cuvette containing 980 micro liter 25 mM
sodium phosphate buffer (pH 7.0) and 10 micro liter of substrate
solution (10 mM linoleic acid dispersed with 0.2%(v/v) Tween20
(should not be kept for extended time periods)). The enzyme is
typically diluted sufficiently to ensure a turnover of maximally
10% of the added substrate within the first minute. The absorbance
at 234 nm is followed and the rate is estimated from the linear
part of the curve. The cis-trans-conjugated hydro(pero)xy fatty
acids are assumed to have a molecular extinction coefficient of
23,000 M.sup.-1cm.sup.-1.
[0146] Alpha-Amylase Activity (KNU)
[0147] The amylolytic activity may be determined using potato
starch as substrate. This method is based on the break-down of
modified potato starch by the enzyme, and the reaction is followed
by mixing samples of the starch/enzyme solution with an iodine
solution. Initially, a blackish-blue color is formed, but during
the break-down of the starch the blue color gets weaker and
gradually turns into a reddish-brown, which is compared to a
colored glass standard.
[0148] One Kilo Novo alpha amylase Unit (KNU) is defined as the
amount of enzyme which, under standard conditions (i.e. at
37.degree. C.+/-0.05; 0.0003 M Ca.sup.2+; and pH 5.6) dextrinizes
5260 mg starch dry substance Merck Amylum solubile.
[0149] A folder EB-SM-0009.02/01 describing this analytical method
in more detail is available upon request to Novozymes A/S, Denmark,
which folder is hereby included by reference.
[0150] Phytase Activity
[0151] The phytase activity is measured in FYT units, one FYT being
the amount of enzyme that liberates 1 micromole inorganic
ortho-phosphate per min. under the following conditions: pH 5.5;
temperature 37.degree. C.; substrate: sodium phytate
(C.sub.6H.sub.6O.sub.24P.sub.6Na.sub.12) at a concentration of
0.0050 mole/I.
[0152] Determination of FAU Activity
[0153] One Fungal Alpha-Amylase Unit (FAU) is defined as the amount
of enzyme, which breaks down 5.26 g starch (Merck Amylum solubile
Erg. B.6, Batch 9947275) per hour based upon the following standard
conditions:
1 Substrate Soluble starch Temperature 37.theta. C. PH 4.7 Reaction
time 7-20 minutes
[0154] Determination of Acid Alpha-Amylase Activity (AFAU)
[0155] Acid alpha-amylase activity is measured in AFAU (Acid Fungal
AIpha-amylase Units), which are determined relative to an enzyme
standard.
[0156] The standard used is AMG 300 L (from Novozymes A/S, Denmark,
glucoamylase wild-type Aspergillus niger G1, also disclosed in Boel
et al. (1984), EMBO J. 3 (5), p. 1097-1102) and WO 92/00381). The
neutral alpha-amylase in this AMG falls after storage at room
temperature for 3 weeks from approx. 1 FAU/mL to below 0.05
FAU/mL.
[0157] The acid alpha-amylase activity in this AMG standard is
determined in accordance with the following description. In this
method, 1 AFAU is defined as the amount of enzyme, which degrades
5.260 mg starch dry matter per hour under standard conditions.
[0158] Iodine forms a blue complex with starch but not with its
degradation products. The intensity of colour is therefore directly
proportional to the concentration of starch. Amylase activity is
determined using reverse colorimetry as a reduction in the
concentration of starch under specified analytic conditions. 1
2 Standard conditions/reaction conditions: (per minute) Substrate:
Starch, approx. 0.17 g/L Buffer: Citate, approx. 0.03 M Iodine
(I.sub.2): 0.03 g/L CaCl.sub.2: 1.85 mM pH: 2.50 .rho. 0.05
Incubation temperature: 40.theta. C. Reaction time: 23 seconds
Wavelength: lambda = 590 nm Enzyme concentration: 0.025 AFAU/mL
Enzyme working range: 0.01-0.04 AFAU/mL
[0159] If further details are preferred these can be found in
EB-SM-0259.02/01 available on request from Novozymes A/S, Denmark,
and incorporated by reference.
[0160] Acid Alpha-Amylase Units (AAU)
[0161] The acid alpha-amylase activity can be measured in AAU (Acid
Alpha-amylase Units), which is an absolute method. One Acid Amylase
Unit (AAU) is the quantity of enzyme converting 1 g of starch (100%
of dry matter) per hour under standardized conditions into a
product having a transmission at 620 nm after reaction with an
iodine solution of known strength equal to the one of a color
reference.
3 Standard conditions/reaction conditions: Substrate: Soluble
starch. Concentration approx. 20 g DS/L. Buffer: Citrate, approx.
0.13 M, pH = 4.2 Iodine solution: 40.176 g potassium iodide + 0.088
g iodine/L City water 15.theta.-20.theta. dH (German degree
hardness) pH: 4.2 Incubation temperature: 30.theta. C. Reaction
time: 11 minutes Wavelength: 620 nm Enzyme concentration: 0.13-0.19
AAU/mL Enzyme working range: 0.13-0.19 AAU/mL
[0162] The starch should be Lintner starch, which is a thin-boiling
starch used in the laboratory as calorimetric indicator. Lintner
starch is obtained by dilute hydrochloric acid treatment of native
starch so that it retains the ability to color blue with iodine.
Further details can be found in EP0140410B2, which disclosure is
hereby included by reference.
[0163] Glucoamylase Activity (AGI)
[0164] Glucoamylase (equivalent to amyloglucosidase) converts
starch into glucose. The amount of glucose is determined here by
the glucose oxidase method for the activity determination. The
method described in the section 76-11 Starch-Glucoamylase Method
with Subsequent Measurement of Glucose with Glucose Oxidase in
"Approved methods of the American Association of Cereal Chemists".
Vol.1-2 AACC, from American Association of Cereal Chemists, (2000);
ISBN: 1-891127-12-8.
[0165] One glucoamylase unit (AGI) is the quantity of enzyme which
will form 1 micromol of glucose per minute under the standard
conditions of the method.
4 Standard conditions/reaction conditions: Substrate: Soluble
starch. Concentration approx. 16 g dry matter/L. Buffer: Acetate,
approx. 0.04 M, pH = 4.3 pH: 4.3 Incubation temperature: 60.theta.
C. Reaction time: 15 minutes Termination of the reaction: NaOH to a
concentration of approximately 0.2 g/L (pH.about.9) Enzyme
concentration: 0.15-0.55 AAU/mL.
[0166] The starch should be Lintner starch, which is a thin-boiling
starch used in the laboratory as colorimetric indicator. Lintner
starch is obtained by dilute hydrochloric acid treatment of native
starch so that it retains the ability to color blue with
iodine.
[0167] Glucoamylase Activity (AGU)
[0168] The Novo Glucoamylase Unit (AGU) is defined as the amount of
enzyme, which hydrolyzes 1 micromole maltose per minute under the
standard conditions 37.degree. C., pH 4.3, substrate: maltose 23.2
mM, buffer: acetate 0.1 M, reaction time 5 minutes.
[0169] An autoanalyzer system may be used. Mutarotase is added to
the glucose dehydrogenase reagent so that any alpha-D-glucose
present is turned into beta-D-glucose. Glucose dehydrogenase reacts
specifically with beta-D-glucose in the reaction mentioned above,
forming NADH which is determined using a photometer at 340 nm as a
measure of the original glucose concentration.
5 AMG incubation: Substrate: maltose 23.2 mM Buffer: acetate 0.1 M
pH: 4.30 .+-. 0.05 Incubation temperature: 37.degree. C. .+-. 1
Reaction time: 5 minutes Enzyme working range: 0.5-4.0 AGU/mL Color
reaction: GlucDH: 430 U/L Mutarotase: 9 U/L NAD: 0.21 mM Buffer:
phosphate 0.12 M; 0.15 M NaCl pH: 7.60 .+-. 0.05 Incubation
temperature: 37.degree. C. .+-. 1 Reaction time: 5 minutes
Wavelength: 340 nm
[0170] A folder (EB-SM-0131.02/01) describing this analytical
method in more detail is available on request from Novozymes A/S,
Denmark, which folder is hereby included by reference.
[0171] Cutinase Activity (LU)
[0172] The cutinase activity is determined as lipolytic activity
determined using tributyrine as substrate. This method was based on
the hydrolysis of tributyrin by the enzyme, and the alkali
consumption is registered as a function of time. One Lipase Unit
(LU) is defined as the amount of enzyme which, under standard
conditions (i.e. at 30.0 degree celsius; pH 7.0; with Gum Arabic as
emulsifier and tributyrine as substrate) liberates 1 micro mol
titrable butyric acid per minute. A folder AF 95/5 describing this
analytical method in more detail is available upon request from
Novozymes A/S, Denmark, which folder is hereby included by
reference.
[0173] Xylanolytic Activity (FXU)
[0174] The xylanolytic activity can be expressed in FXU-units,
determined at pH 6.0 with remazol-xylan
(4-O-methyl-D-glucurono-D-xylan dyed with Remazol Brilliant Blue R,
Fluka) as substrate.
[0175] A xylanase sample is incubated with the remazol-xylan
substrate. The background of non-degraded dyed substrate is
precipitated by ethanol. The remaining blue color in the
supernatant (as determined spectrophotometrically at 585 nm) is
proportional to the xylanase activity, and the xylanase units are
then determined relatively to an enzyme standard at standard
reaction conditions, i.e. at 50.0.degree. C., pH 6.0, and 30
minutes reaction time.
[0176] A folder EB-SM-352.02/01 describing this analytical method
in more detail is available upon request to Novozymes A/S, Denmark,
which folder is hereby included by reference.
[0177] Cellulytic Activity (EGU)
[0178] The cellulytic activity may be measured in endo-glucanase
units (EGU), determined at pH 6.0 with carboxymethyl cellulose
(CMC) as substrate. A substrate solution is prepared, containing
34.0 g/l CMC (Hercules 7 LFD) in 0.1 M phosphate buffer at pH 6.0.
The enzyme sample to be analyzed is dissolved in the same buffer. 5
ml substrate solution and 0.15 ml enzyme solution are mixed and
transferred to a vibration viscosimeter (e.g. MIVI 3000 from
Sofraser, France), thermostated at 40.degree. C. for 30 minutes.
One EGU is defined as the amount of enzyme that reduces the
viscosity to one half under these conditions. The amount of enzyme
sample should be adjusted to provide 0.01-0.02 EGU/ml in the
reaction mixture. The arch standard is defined as 880 EGU/g.
[0179] A folder EB-SM-0275.02/01 describing this analytical method
in more detail is available upon request to Novozymes A/S, Denmark,
which folder is hereby included by reference.
EXAMPLES
Example 1
[0180] Measurement of the Activity of Fatty Acid Oxidizing Enzymes
on Linoleic Acid
[0181] An "Oxi 3000 Oximeter" (WTW, Weilheim, Germany) with a
TriOxmatic 300 oxygen electrode and a standard reaction volume of 4
ml was used.
[0182] 10 mg linoleic acid (10 ml 60% linoleic acid) was dissolved
in 1 ml ethanol, and 2 micro liter Tween 20 was added. From this
stock substrate solution 50 micro liter was added into a reaction
beaker containing 3.85 ml buffer solution (Britton-Robinson: 100 mM
of Phosphoric-, Acetic- and Boric acid; pH adjusted with NaOH) with
a small stir bar allowing the solution to be mixed well, and the
oxygen electrode was inserted into the reaction beaker. 100 micro
liter purified enzyme solution was added, viz. (a) lipoxygenase
derived from Magnaporthe salvinii at a concentration of approx. 0.4
mg/ml; or (b) lipoxygenase derived from Gaeumannomyces graminis at
a concentration of approx. 0.76 mg/ml (which means approximately
0.02 mg/ml in the final reaction). These lipoxygenases were
prepared as previously described. The temperature was 25.theta.C.
The concentration of dissolved oxygen (mg/l) is measured and
plotted as a function of time (min.). The enzymatic activity is
calculated as the slope of the linear part of the curve (mg/l/min.)
after addition of the enzyme. The baseline was corrected by
subtraction when relevant, meaning that if the curve showing oxygen
concentration as a function of time had a slope of above about 0.05
mg oxygen/ml/min before addition of the fatty acid oxidizing enzyme
(i.e. the control), this value was subtracted from the sample slope
value.
[0183] Table 1 below shows the results of the experiments.
6 TABLE 1 Fatty Acid Oxidizing Enzyme (a) LOX from M. salvinii (b)
LOX from G. graminis pH mgO.sub.2/ml/min mgO.sub.2/ml/min 2 0.0 0.0
4 0.4 0.1 5 0.7 0.4 6 1.1 0.4 7 1.0 0.4 8 0.7 0.5 9 0.8 0.4 10 0.7
0.4 11 0.6 0.2
Example 2
[0184] Fatty Acid Oxidizing Enzymes
[0185] Four enzymes, viz. two laccases and two lipoxygenases were
tested as described below. The laccase derived from Polyporus
pinsitus had a MW by SDS-Page of 65 kDa, a pl by IEF of 3.5, and an
optimum temperature at pH 5.5 of 60.theta.C. The laccase derived
from Coprinus cinereus had a MW by SDS-Page of 67-68 kDa, a pl by
IEF of 3.5-3.8, and an optimum temperature at pH 7.5 of 65.theta.C.
The enzymes were prepared and purified as described in WO 96/00290
and U.S. Pat. No. 6,008,029. The two lipoxygenases were derived
from Magnaporthe salvinii and Gaeumannomyces graminis, and they
were prepared as described previously.
[0186] The enzyme dosage was adjusted to ensure maximum absorbancy
increase per minute at 234 nm/530 nm, viz. in the range of 0.1-0.25
absorbancy units pr. min.
[0187] Substrate solution: 11.65 mg linoleic acid (60% Sigma), as
well as 12.5 ml 0.56 mM Syringaldazine (Sigma) in ethanol was mixed
with deionized water to a total volume of 25 ml.
[0188] 50 microliter of the enzyme preparation to be tested was
transferred to a quartz cuvette containing 900 microliter phosphate
buffer (50 mM, pH 7.0) and 50 microliter of the substrate solution
The cuvette was placed in a spectrofotometer, thermostated at
23.theta.C, and the absorbancies at 234 nm and 530 nm were measured
as a function of time. The absorbancy at 530 nm is indicative of
degradation of syringaldazine, whereas the absorbancy at 234 nm is
indicative of degradation of linoleic acid. The absorbancy increase
as a function of time is calculated on the basis of minutes 2 to 4
of the reaction time, i.e. d(A.sub.234)/dt, as well as
d(A.sub.530)/dt.
[0189] The results are shown in Table 2 below. Of these four
enzymes, only the two lipoxygenases qualify as a fatty acid
oxidizing enzyme as defined herein. This is because RRD=Reaction
Rate Difference=(dA.sub.234/dt-dA.su- b.530/dt) is above zero only
for these two enzymes.
7TABLE 2 dA.sub.530/dt dA.sub.234/dt dA.sub.234/dt - dA.sub.530/dt
Enzyme (units/min) (units/min) (units/min) Polyporus pinsitus 0.20
0.002* -0.20 laccase Magnaporthe salvinii 0.0001* 0.13 0.13
lipoxygenase Coprinus cinereus 0.17 -0.001* -0.17 laccase
Gaeumannomyces -0.03* 0.21 0.21 graminis lipoxygenase *this is
equivalent to zero activity (analytical inaccuracy)
Example 3
[0190] SSF Fermentation Including 50% w/w Backset
[0191] Raw starch hydrolysis (RSH) was carried out as follows:
Ethanol Red yeast was propagated aerobically at 500 rpm and
32.2.degree. C. for 8 hours in the presence of 0.02% DS NOVOZYM
50006.TM.. A corn slurry (36% DS) was prepared by mixing ground
corn (2-mm screen), tap water and backset followed by pH adjustment
to pH 5 with phosphoric acid. The content of backset was 50% w/w of
the liquid phase. SP 288, 0.8 AFAU/g DS, SPIRIZYME.TM. FUEL, 2
AGU/g DS, and yeast propagate was introduced into the slurry
immediately before filling 25-ml fermentors equipped with the air
locks. The air locks were provided with 0.2-micro m syringe filters
to prevent oil backflow and microbial contaminations. The
fermentation was carried out at 32.2.degree. C. for 64 hours. When
fermentation was completed fermenters were spin down at 3,000 rpm
at 20.degree. C. for 15 minutes. The supernatant was forced through
a 0.45-micro m filter and analyzed by HPLC.
8 TABLE 1 Backset, % Ethanol, % v/v Control 19.81 50 17.77
[0192] Effect of backset concentration on 64-hours ethanol yield in
RSH. Data are average of 7 fermentations done at different
time.
[0193] Table 1 shows that the addition of backset to the
fermentation medium decreases the ethanol yield.
Example 4
[0194] SSF Fermentation with Magnaporthe salvinii Lipoxygenase
Pretreated Fermentation Medium and 50% Backset
[0195] The experiment described in Example 3 was repeated using a
fermentation medium pretreated with lipoxygenase and lipoxygenase
with lipase incorporated in the fermentation medium.
9TABLE 2 Lipoxygenase activity, Activity, Ethanol, U/g DS Lipase
LU/g DS % v/v in beer 0 -- -- 17.77 9.3 -- -- 18.76 9.3 LIPOLASE
.TM. 100 L 5 19.13
[0196] Table 2 shows that 1) lipoxygenase and 2) lipoxygenase and
lipase pretreatment of the fermentation medium increases the
ethanol yields.
* * * * *
References