U.S. patent application number 14/299008 was filed with the patent office on 2014-09-25 for processing biomass materials.
The applicant listed for this patent is Xyleco, Inc.. Invention is credited to John J. BAXTER, Thomas Craig MASTERMAN, Marshall MEDOFF.
Application Number | 20140284277 14/299008 |
Document ID | / |
Family ID | 51491991 |
Filed Date | 2014-09-25 |
United States Patent
Application |
20140284277 |
Kind Code |
A1 |
MEDOFF; Marshall ; et
al. |
September 25, 2014 |
PROCESSING BIOMASS MATERIALS
Abstract
Biomass (e.g., plant biomass, animal biomass, and municipal
waste biomass) is processed to produce useful intermediates and
products, such as energy, fuels, foods or materials. For example,
equipment, systems and methods are described that can be used to
treat feedstock materials, such as cellulosic and/or
lignocellulosic materials. Process streams can be upgraded, e.g.,
by removing undesired components utilizing simulated moving bed
systems such as simulated moving bed chromatography, improved
simulated moving bed chromatography, sequential simulated moving
bed chromatography and/or related systems.
Inventors: |
MEDOFF; Marshall;
(Brookline, MA) ; MASTERMAN; Thomas Craig;
(Rockport, MA) ; BAXTER; John J.; (Amesbury,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Xyleco, Inc. |
Woburn |
MA |
US |
|
|
Family ID: |
51491991 |
Appl. No.: |
14/299008 |
Filed: |
June 9, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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PCT/US14/21638 |
Mar 7, 2014 |
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14299008 |
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61774684 |
Mar 8, 2013 |
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61774773 |
Mar 8, 2013 |
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61774731 |
Mar 8, 2013 |
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61774735 |
Mar 8, 2013 |
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61774740 |
Mar 8, 2013 |
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61774744 |
Mar 8, 2013 |
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61774746 |
Mar 8, 2013 |
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61774750 |
Mar 8, 2013 |
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61774752 |
Mar 8, 2013 |
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61774754 |
Mar 8, 2013 |
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61774775 |
Mar 8, 2013 |
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61774780 |
Mar 8, 2013 |
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61774761 |
Mar 8, 2013 |
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61774723 |
Mar 8, 2013 |
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61793336 |
Mar 15, 2013 |
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Current U.S.
Class: |
210/656 |
Current CPC
Class: |
C10L 2290/36 20130101;
G21K 5/10 20130101; C07C 31/12 20130101; C12P 7/04 20130101; C12P
7/56 20130101; C10G 1/00 20130101; E04B 1/92 20130101; C13K 13/002
20130101; B01D 15/02 20130101; Y02E 50/30 20130101; Y02W 10/40
20150501; C10L 9/08 20130101; C12P 19/14 20130101; H01J 37/317
20130101; B01J 2219/0886 20130101; C10L 2200/0476 20130101; B65G
27/00 20130101; B01J 2219/0879 20130101; C10L 1/023 20130101; C12P
19/02 20130101; B01D 61/44 20130101; B65G 53/04 20130101; C13K 1/02
20130101; C10L 1/026 20130101; Y02W 10/37 20150501; C10L 2200/0469
20130101; Y02P 20/133 20151101; C12P 7/52 20130101; H01J 2237/202
20130101; Y02E 50/10 20130101; H01J 2237/3165 20130101; C12P 7/10
20130101; B65G 53/40 20130101; Y02W 10/33 20150501; B01D 61/445
20130101; D21C 9/007 20130101; Y02E 60/16 20130101; B01J 19/085
20130101; B01J 2219/0869 20130101; C07C 29/149 20130101; C12M 47/00
20130101; G21F 7/00 20130101; C12P 2203/00 20130101; E04B 2001/925
20130101; B01D 53/32 20130101; C12P 7/06 20130101; H01J 2237/31
20130101; C12M 47/10 20130101; C12P 2201/00 20130101; C07C 29/149
20130101; C07C 31/12 20130101 |
Class at
Publication: |
210/656 |
International
Class: |
B01D 15/02 20060101
B01D015/02 |
Claims
1. A method of upgrading a process stream, the method comprising:
removing undesired components from saccharified biomass liquids,
utilizing a simulated moving bed chromatography system.
2. The method of claim 1, wherein the saccharified biomass liquids
is derived from a reduced recalcitrance cellulosic or
lignocellulosic material that has been saccharified.
3. The method of claim 2, wherein the cellulosic or lignocellulosic
material has had its recalcitrance reduced by treatment with
ionizing radiation.
4. The method of claim 3, wherein the ionizing radiation is in the
form of accelerated electrons.
5. The method of claim 2, wherein the cellulosic or lignocellulosic
material has been saccharified utilizing one or more enzymes.
6. The method of claim 1, wherein the undesired components are
selected from the group consisting of colored bodies, soluble
lignin fragments, ionic compounds or mixtures thereof.
7. The method of claim 1, wherein the saccharified biomass liquids
comprise one or more mono saccharide.
8. The method of claim 7, wherein the one or more mono saccharide
is selected from the group consisting of glucose, xylose, arabinose
and mixtures thereof.
9. The method of claim 7, wherein the one or more mono saccharide
is present at a total concentration of between about 50 g/L and
about 500 g/L.
10. The method of claim 1, wherein the saccharified biomass liquids
enter the simulated moving bed chromatography system at a first
concentration and the liquids exit the simulated moving bed
chromatography system at a second concentration that is from about
0.1 to about 0.90 times the first concentration.
11. The method of claim 1, wherein the saccharified biomass liquids
include less than about 0.1 percent suspended solids.
12. The method of claim 1, wherein the saccharified biomass liquids
include suspended solids having a particle size in the range of
between about 0.05 micron and about 50 microns.
13. The method of claim 1, further comprising treating the
saccharified biomass liquids by a method selected from the group
consisting of chromatography, filtration, centrifugation,
precipitation, distillation, complexation, de-ionization and
combinations thereof, prior to utilizing the simulated moving bed
chromatography system to remove undesired components.
14. The method of claim 1, wherein the saccharified biomass liquids
comprise one or more saccharides and one or more fermentation
products.
15. The method of claim 14, wherein the fermentation product is an
alcohol.
16. The method of claim 15, wherein the alcohol is ethanol.
17. The method of claim 14, wherein the one or more saccharides
comprise xylose.
18. The method of claim 14, wherein the one or more fermentation
products are isolated by distillation.
19. The method of claim 1, further comprising decolorizing the
saccharified biomass liquids with a decolorizing agent prior to
utilizing the simulated moving bed chromatography system, wherein
the decolorizing agent is selected from the group consisting of
powdered carbon, granular carbon, extruded carbon, bone char
carbon, bead activated carbon, styrenic resins, acrylic resins,
magnetic resins, decolorizing clays, bentonite, attapulgite,
montmorillonite, hormite, and combinations thereof.
20. The method of claim 19, wherein after decolorizing, the color
of the solution is less than about 100 as measured by the
Platinum-Cobalt method.
21. The method of claim 1, wherein the simulated moving bed
chromatography system allows for contacting of the saccharified
biomass liquids with one or more resins packed in one or more
columns so as to remove the undesired components.
22. The method of claim 21, wherein the one or more resins comprise
a polystyrenic resin.
23. The method of claim 21, wherein the one or more resins include
a pendent cation, selected from the group consisting of Al.sup.3+,
Me.sup.2+, Ca.sup.2+, Sr.sup.2+, Li.sup.+, Na.sup.+, K.sup.+,
Rb.sup.+ and combinations thereof.
24. The method of claim 21, wherein the one or more resins include
a pendent functional group selected from the group consisting of
sulfonate groups, sulfonic acid groups, ester groups and
combinations thereof.
25. The method of claim 21, wherein the one or more resins are
crosslinked resins.
26. The method of claim 21, wherein the one or more resins are
substantially spherical in shape, and the resins have a particle
size between about 100 micron to about 500 micron.
27. The method of claim 21, wherein the one or more resins have a
density of between about 1 g/cc to about 1.75 g/cc.
28. The method of claim 21, wherein the one or more resins have an
ion exchange capacity of greater than about 1.0 meq/mL.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of PCT/US14/21638 filed
Mar. 7, 2014 which claims priority to the following provisional
applications: U.S. Ser. No. 61/774,684, filed Mar. 8, 2013; U.S.
Ser. No. 61/774,773, filed Mar. 8, 2013; U.S. Ser. No. 61/774,731,
filed Mar. 8, 2013; U.S. Ser. No. 61/774,735, filed Mar. 8, 2013;
U.S. Ser. No. 61/774,740, filed Mar. 8, 2013; U.S. Ser. No.
61/774,744, filed Mar. 8, 2013; U.S. Ser. No. 61/774,746, filed
Mar. 8, 2013; U.S. Ser. No. 61/774,750, filed Mar. 8, 2013; U.S.
Ser. No. 61/774,752, filed Mar. 8, 2013; U.S. Ser. No. 61/774,754,
filed Mar. 8, 2013; U.S. Ser. No. 61/774,775, filed Mar. 8, 2013;
U.S. Ser. No. 61/774,780, filed Mar. 8, 2013; U.S. Ser. No.
61/774,761, filed Mar. 8, 2013; U.S. Ser. No. 61/774,723, filed
Mar. 8, 2013; and U.S. Ser. No. 61/793,336, filed Mar. 15, 2013.
The full disclosure of each of these applications is incorporated
by reference herein.
BACKGROUND OF THE INVENTION
[0002] Many potential lignocellulosic feedstocks are available
today, including agricultural residues, woody biomass, municipal
waste, oilseeds/cakes and seaweed, to name a few. At present, these
materials are often under-utilized, being used, for example, as
animal feed, biocompost materials, burned in a co-generation
facility or even landfilled.
[0003] Lignocellulosic biomass includes crystalline cellulose
fibrils embedded in a hemicellulose matrix, surrounded by lignin.
This produces a compact matrix that is difficult to access by
enzymes and other chemical, biochemical and/or biological
processes. Cellulosic biomass materials (e.g., biomass material
from which the lignin has been removed) is more accessible to
enzymes and other conversion processes, but even so,
naturally-occurring cellulosic materials often have low yields
(relative to theoretical yields) when contacted with hydrolyzing
enzymes. Lignocellulosic biomass is even more recalcitrant to
enzyme attack. Furthermore, each type of lignocellulosic biomass
has its own specific composition of cellulose, hemicellulose and
lignin.
SUMMARY
[0004] This invention relates to methods and processing equipment
used for producing and purifying products from saccharified biomass
materials. Generally, the methods include treating a recalcitrant
biomass, e.g., with electron beams and then biochemically and/or
chemically processing the reduced recalcitrance material to a
mixture of sugars, for example, xylose and glucose and/or other
products, such as alcohols, e.g., ethanol or a butanol, sugar
alcohols, e.g., xylitol, D-lactic acid, L-lactic acid succinic acid
or pyruvic acid. The methods include upgrading or improving process
streams, e.g., by separating the sugars or other products from the
saccharified and/or fermented biomass using Simulated Moving Bed
Chromatography systems (SMB) (e.g., simulated moving bed
chromatography, improved simulated moving bed chromatography,
sequential simulated moving bed chromatography and/or related
systems) which utilize several columns (e.g., in series) containing
resins capable of separating various components, e.g., the sugars,
from the other components. Prior to subjecting the process stream,
e.g., sugar solution, to a simulated moving bed system, the biomass
liquids can be also be treated to remove other unwanted components
(e.g., impurities) and color (e.g., colored impurities, color
bodies) that are often generated during the processing of the
feedstock material.
[0005] In one aspect the invention relates to methods of upgrading
a process steam including removing undesired components from
biomass liquids utilizing a simulated moving bed chromatography
system (e.g., simulated moving bed chromatography, improved
simulated moving bed chromatography, sequential simulated moving
bed chromatography and/or related systems). For example, the
undesired components can include components from the group
consisting of colored bodies, soluble lignin fragments, ionic
compounds and mixtures of these. Optionally the saccharified
biomass liquids can be derived from a reduced recalcitrance
lignocellulosic or cellulosic material, such as wherein the
recalcitrance is reduced by treatment of the material by
irradiation with ionizing radiation (e.g., in the form of
accelerated electrons). Optionally the biomass has been
saccharified utilizing one or more enzymes and/or or one or more
acids (e.g., sulfuric acid). Biomass liquids include, for example,
sugar solutions from saccharified biomass and fermented sugar
solutions, e.g., fermented to consume one or more of the available
sugars.
[0006] In some implementations the saccharified biomass liquids
include one or more saccharides and/or monosaccharides from which
the biomass (e.g., cellulose and/or lignocellulos) is comprised,
such as monosaccharide selected from the group consisting of
glucose, xylose, arabinose and mixtures of these. Optionally the
one or more monosaccharides are present at a total concentration of
between about 50 g/L and about 500 g/L, such as between about 100
g/L to about 400 g/L, from about 150 g/L to about 350 g/L or from
about 175 g/L to about 275 g/L. In addition, the invention can
include methods wherein biomass liquids enter the simulated moving
bed chromatography system (e.g., simulated moving bed
chromatography, improved simulated moving bed chromatography,
sequential simulated moving bed chromatography and/or related
systems) at a first concentration and exit the simulated moving bed
chromatography (e.g., with undesired components removed) at a
second concentration that is from about 0.1 to about 0.90 times the
entering concentration (e.g., such as between about 0.25 to about
0.8, from about 0.3 to about 0.7, or from about 0.40 to about
0.65). Alternatively stated, at least one of the components exits
the SMB system at 0.1 to about 0.9 times the concentration of the
concentration that it enters the SMB system, for example, if the
initial concentration of at least one component in the liquids is
100 g/mL, the final concentration can be between about 10 and 90
g/L.
[0007] In some implementations, the saccharified biomass liquids
include less than about 1 percent suspended solids, such as less
about 0.75 percent, less than about 0.5 percent, less than about
0.4 percent, less than about 0.3 percent, less than about 0.25
percent, less than about 0.20 percent, less than about 0.15
percent, less than about 0.10 percent, less than about 0.05
percent, less than about 0.025 percent, or even less than about
0.010 percent. In addition or independently, any suspended solids
can have a particle size range of between about 0.05 micron and
about 50 micron, such as between about 0.1 micron and about 25
micron, about 0.2 micron and about 10 micron, about 0.22 micron and
about 5 micron or between about 0.25 micron and about 1 micron.
[0008] In another implementation, prior to utilizing the simulated
moving bed chromatography (e.g., simulated moving bed
chromatography, improved simulated moving bed chromatography,
sequential simulated moving bed chromatography, and/or related
systems) to remove undesired components, the saccharified biomass
liquids can be treated by a purification method selected from the
group consisting of chromatography, filtration, centrifugation,
precipitation, distillation, complexation, de-ionization and
combinations of these methods.
[0009] In some implementations the saccharified biomass liquids
comprise one or more saccharides and one or more fermentation
products, such as an alcohol, e.g., ethanol. Optionally the one or
more saccharides include xylose and the one or more fermentation
products include ethanol. Optionally, the one or more fermentation
products are isolated by distillation.
[0010] In some implementations the methods further include
decolorizing the saccharified biomass liquids with a decolorizing
agent prior to utilizing the simulated moving bed chromatography
system (e.g., simulated moving bed chromatography, improved
simulated moving bed chromatography, sequential simulated moving
bed chromatography, and/or similar systems). For example, the
decolorizing agent can be selected from the group consisting of
powdered carbon, granular carbon, extruded carbon, bone char
carbon, bead activated carbon, styrenic resins, acrylic resins,
magnetic resins, decolorizing clays, bentonite, attapulgite,
montmorillonite, hormite and combinations of these. Optionally,
after decolorizing the solution can have a color of less than about
100 as measured by the Platinum-Cobalt method, such as less than
about 50, less than about 40, less than about 30, less than about
20, less than about 10, less than about 5 and even less than about
1.
[0011] In yet other implementations, the simulated moving bed
chromatography (e.g., simulated moving bed chromatography, improved
simulated moving bed chromatography, sequential simulated moving
bed chromatography, and/or related systems) system allows for
contacting of saccharified biomass liquids with one or more resins
packed in one or more columns so as to remove undesired components.
For example, the resins can include polystyrenic resin.
Alternatively or additionally, the one or more resins can further
include pendent cations selected from the group consisting of
Al.sup.3+, Me.sup.2+, Ca.sup.2+, Sr.sup.2+, Li.sup.+, Na.sup.+,
K.sup.+, Rb.sup.+ and combinations of these. Optionally, the one or
more resins include pendent functional groups selected from the
group consisting of sulfonate groups, sulfonic acid groups, an
ester group and combinations of these. Optionally, the one or more
resins are crosslinked resins, such as crosslinked by one or more
divinyl compounds, such as divinyl benzene. Optionally, the one or
more resins can be substantially spherical in shape, and the resins
can have a particle size between about 100 micron to about 500
micron, such as between about 150 micron to about 400 micron,
between about 200 micron to about 350 micron. Optionally, the one
or more resins can have a density of between about 1 g/cc to about
1.75 g/cc, such as between about 1.1 g/cc to about 1.4 g/cc or
between about 1.2 g/cc and about 1.35 g/cc. The one or more resins
can have an ion exchange capacity of greater than about 1.0 meq/mL,
such as greater than about 1.1, greater than about 1.2, greater
than about 1.3, greater than about 1.4, greater than about 1.6,
greater than about 1.75, greater than about 2, or even greater than
about 2.3.
[0012] Purifying sugar solutions derived from biomass provides a
more valuable product that can be utilized, for example, in the
food, pharmaceutical or chemical industry. For example, sugars free
of undesired components can be utilized as a food source for human
and animal consumption. The sugars can also be utilized as a
carbohydrate source for technologically important fermentations.
Alternatively, these sugars can be converted to other products, for
example, polyols and furfurals as described in U.S. Ser. No.
13/934,704 filed Mar. 7, 2013, the entire disclosure of which is
herein incorporated by reference.
[0013] Implementations of the invention can optionally include one
or more of the following summarized features. In some
implementations, the selected features can be applied or utilized
in any order while in other implementations a specific selected
sequence is applied or utilized. Individual features can be applied
or utilized more than once in any sequence and even continuously.
In addition, an entire sequence, or a portion of a sequence, of
applied or utilized features can be applied or utilized once,
repeatedly or continuously in any order. In some optional
implementations, the features can be applied or utilized with
different, or where applicable the same, set or varied,
quantitative or qualitative parameters as determined by a person
skilled in the art. For example, parameters of the features such as
size, individual dimensions (e.g., length, width, height), location
of, degree (e.g., to what extent such as the degree of
recalcitrance), duration, frequency of use, density, concentration,
intensity and speed can be varied or set, where applicable, as
determined by a person of skill in the art.
[0014] Features, for example, include: A method of upgrading a
process stream; removing undesired components from saccharified
biomass liquids, utilizing a simulated moving bed chromatography
system; a saccharified biomass liquid is derived from a reduced
recalcitrance cellulosic or lignocellulosic material that has been
saccharified; a cellulosic or lignocellulosic material has had its
recalcitrance reduced by treatment with ionizing radiation; a
cellulosic or lignocellulosic material has had its recalcitrance
reduced by treatment with accelerated electrons; a cellulosic or
lignocellulosic material has been saccharified utilizing one or
more enzymes; a cellulosic or lignocellulosic material has been
saccharified utilizing one or more acids; a cellulosic or
lignocellulosic material has been saccharified utilizing sulfuric
acid; undesired components in a saccharified biomass liquid
includes colored bodies; undesired components in a saccharified
biomass liquid includes soluble lignin fragments; undesired
components in a saccharified biomass liquid includes ionic
compounds; a saccharified biomass liquid includes one or more mono
saccharides; a saccharified biomass liquid includes glucose; a
saccharified biomass liquid includes xylose; a saccharified biomass
liquid includes arabinose; a saccharified biomass liquid includes
one or more mono saccharide(s) present at a total concentration of
between about 50 g/L and about 500 g/L; a saccharified biomass
liquid includes one or more mono saccharide(s) present at a total
concentration of between about 100 g/L to about 400 g/L; a
saccharified biomass liquid includes one or more mono saccharide(s)
present at a total concentration of between about 150 g/L to about
350 g/L; a saccharified biomass liquid enters a simulated moving
bed chromatography system at a first concentration and the liquid
exits the simulated moving bed chromatography system at a second
concentration that is from about 0.1 to about 0.90 times the first
concentration; a saccharified biomass liquid include less than
about 1 percent suspended solids; a saccharified biomass liquid
include less than about 0.1 percent suspended solids; a
saccharified biomass liquid include suspended solids having a
particle size in the range of between about 0.05 micron and about
50 microns; a saccharified biomass liquid is upgraded by a method
including chromatography prior to utilizing the simulated moving
bed chromatography system to remove undesired components; a
saccharified biomass liquid is upgraded by a method including
filtration prior to utilizing the simulated moving bed
chromatography system to remove undesired components; a
saccharified biomass liquid is upgraded by a method including
centrifugation; a saccharified biomass liquid is upgraded by a
method including precipitation; a saccharified biomass liquid is
upgraded by a method including distillation; a saccharified biomass
liquid is upgraded by a method including complexation; a
saccharified biomass liquid is upgraded by a method including
de-ionization; a saccharified biomass liquid comprises one or more
saccharides and one or more fermentation products; a saccharified
biomass liquid comprises one or more saccharides and one or more
alcohol that is a fermentation product; a saccharified biomass
liquid comprises one or more saccharides and ethanol that is a
fermentation product; a saccharified biomass liquid that includes
xylose and one or more fermentation products; a saccharified
biomass liquid that comprises one or more saccharides and one or
more fermentation products, and the fermentation product is
isolated by distillation; decolorizing a saccharified biomass
liquid with a decolorizing agent; decolorizing a saccharified
biomass liquid utilizing powdered carbon; decolorizing a
saccharified biomass liquid utilizing granular carbon; decolorizing
a saccharified biomass liquid utilizing extruded carbon;
decolorizing a saccharified biomass liquid utilizing bone char
carbon; decolorizing a saccharified biomass liquid utilizing bead
activated carbon; decolorizing a saccharified biomass liquid
utilizing styrenic resin; decolorizing a saccharified biomass
liquid utilizing acrylic resins; decolorizing a saccharified
biomass liquid utilizing magnetic resins; decolorizing a
saccharified biomass liquid utilizing decolorizing clays;
decolorizing a saccharified biomass liquid utilizing bentonite;
decolorizing a saccharified biomass liquid utilizing attapulgite;
decolorizing a saccharified biomass liquid utilizing
montmorillonite; decolorizing a saccharified biomass liquid
utilizing hormite; decolorizing a saccharified biomass liquid
utilizing a decolorizing agent so that the color of the solution is
less than about 100 as measured by the Platinum-Cobalt method;
contacting of a saccharified biomass liquid with one or more resins
packed in one or more columns so as to remove the undesired
components; contacting of a saccharified biomass liquid with one or
more polystyrenic resins packed in one or more columns so as to
remove undesired components; contacting a saccharified biomass
liquid with one or more resins that has a pendent Al.sup.3+ ion,
the resin packed in one or more columns so as to remove undesired
components; contacting a saccharified biomass liquid with one or
more resins that has a pendent Mg.sup.2+ ion, the resin packed in
one or more columns so as to remove undesired components;
contacting a saccharified biomass liquid with one or more resins
that has a pendent Ca.sup.2+ ion, the resin packed in one or more
columns so as to remove undesired components; contacting a
saccharified biomass liquid with one or more resins that has a
pendent Sr.sup.2+ ion, the resin packed in one or more columns so
as to remove undesired components; contacting a saccharified
biomass liquid with one or more resins that has a pendent Li.sup.1+
ion, the resin packed in one or more columns so as to remove
undesired components; contacting a saccharified biomass liquid with
one or more resins that has a pendent Na.sup.1+ ion, the resin
packed in one or more columns so as to remove undesired components;
contacting a saccharified biomass liquid with one or more resins
that has a pendent K.sup.1+ ion, the resin packed in one or more
columns so as to remove undesired components; contacting a
saccharified biomass liquid with one or more resins that has a
pendent Rb.sup.1+ ion, the resin packed in one or more columns so
as to remove undesired components; contacting a saccharified
biomass liquid with one or more resins that has a pendent sulfonate
group, the resin packed in one or more columns so as to remove
undesired components; contacting a saccharified biomass liquid with
one or more resins that has a pendent sulfonic group, the resin
packed in one or more columns so as to remove undesired components;
contacting a saccharified biomass liquid with one or more resins
that has a pendent ester group, the resin packed in one or more
columns so as to remove the undesired components; contacting a
saccharified biomass liquid with one or more crosslinked resins
packed in one or more columns so as to remove the undesired
components; contacting of a saccharified biomass liquid with one or
more resins that are substantially spherical in shape and have a
particle size between about 100 microns and about 500 microns, the
resin packed in one or more columns so as to remove the undesired
components; contacting of a saccharified biomass liquid with one or
more resins that have a density of between about 1 g/cc to about
1.75 g/cc, the resin packed in one or more columns so as to remove
undesired components; contacting a saccharified biomass liquid with
one or more resins that have an ion exchange capacity of greater
than about 1 meq/mL, the resin packed in one or more columns so as
to remove undesired components.
[0015] Other features and advantages of the invention will be
apparent from the following detailed description, and from the
claims.
DESCRIPTION OF DRAWINGS
[0016] FIG. 1 is a diagrammatic overview of an exemplary simulated
moving bed system (SMB).
[0017] FIG. 2 is a flow diagram showing a process for purifying a
saccharified material.
[0018] FIG. 3 is a flow diagram showing a process for purifying a
fermented solution.
DETAILED DESCRIPTION
[0019] Using the methods and systems described herein, cellulosic
and/or lignocellulosic feedstock materials, for example that can be
sourced from biomass (e.g., plant biomass, animal biomass, paper,
and municipal waste biomass) and that are often readily available
but difficult to process, can be converted to solutions containing
sugars such as xylose and glucose, which can optionally be further
processed to other useful products (e.g., alcohols such as ethanol
and butanol). Included are methods and systems for removing
impurities or undesired components from the desired sugar solution
by using Simulated Moving Bed Chromatography (SMB) (e.g., simulated
moving bed chromatography, improved simulated moving bed
chromatography, sequential simulated moving bed chromatography
and/or related systems). For example, systems that use
chromatography columns in series.
[0020] Processes for manufacturing sugar solutions and products
derived therefrom are described herein. These processes may
include, for example, optionally mechanically treating a cellulosic
and/or lignocellulosic feedstock. Before and/or after this
treatment, the feedstock can be treated with another treatment, for
example irradiation, steam explosion, pyrolysis, sonication and/or
oxidation to reduce, or further reduce its recalcitrance. In
addition to or alternatively the biomass can be treated with a
chemical solution such as an acid (H.sub.2SO.sub.4, HCL,
H.sub.3PO.sub.4), a base (KOH), an oxidant and combinations of
these. The chemical solution treatments and physical treatments can
be combinations of the individual treatments in any order and
optionally applied repeatedly.
[0021] A solution rich in sugar can be produced by saccharifying a
treated (e.g., irradiated) biomass feedstock by the addition of one
or more enzymes and/or one or more acids, e.g., sulfuric acid
(e.g., 1-10 wt. %, 1-5 wt. %, or higher e.g., 10-20 wt. %, or in
some embodiments less than 10 wt. %). Several other products can be
derived from the sugar solution, for example, by fermentation to an
alcohol such as ethanol or by reduction to a sugar alcohol such as
xylitol, sorbitol etc. The product of the fermentation can include
a sugar solution (e.g., a second sugar solution, a fermented
solution) including any non-fermented sugars. In some embodiments,
the saccharified material is fermented and then fermentation
products (e.g., an alcohol, an acid) can be purified by
distillation (e.g., vacuum distillation) or other means (e.g.,
extraction on a resin), producing a distillation bottom that
includes a solution rich in at least one unfermented sugar. For
example, a saccharified material can be treated with an organism
that selectively ferments glucose to ethanol and the ethanol can be
distilled away producing a distillate bottom containing at least
about 400 g/L of xylose, e.g. at least about 10, 50, 75, 100, 125,
150, 175, 200, 250, 325 or 375 g/L and between 1-80% of dissolved
solids, e.g. between 1-10, 10-20, 20-30, 30-40, 40-50, 50-60,
60-70, 70-80, 5-25, 25-50, 50-75% dissolved solids.
[0022] The saccharification and optionally further processed (e.g.,
fermented and/or distilled) cellulosic or lignocellulosic materials
can produce solutions that include one or more monosaccharides, for
example glucose, xylose and arabinose. The total concentration of
these monosaccharides in the saccharified and/or fermented
cellulosic or lignocellulosic biomass liquids can be between about
50 g/L and 500 g/L (e.g., between about 100 and 400 g/L, between
about 150 and 350 g/L, between about 175 and 275 g/L. These
concentration ranges can be the concentrated or diluted
concentrations of the solutions and/or these solutions can be
further concentrated or diluted before, during or after any of the
processing described herein (e.g., before, during or after
processing with SMB). For example the solutions can be diluted by
between about 0.10-50 times the original volume (e.g., diluted by
between about 0.1-20 times, between about 0.1-10 times, between
about 0.10-8 times, between about 0.25-8 times, between about 0.3-7
times, between about 0.4-6.5 times, between about 0.10-5 times,
between about 0.15-3 times, between about 0.1-2.5 times, between
about 0.10-1 times), for example, if the original volume is 100 L
and the solution is diluted by 0.4 times, the final solution will
be 140 L. The solutions can be concentrated (e.g., the original
volume can be reduced) by between about 0.1-0.9 times the original
volume (e.g., by between about 0.1 and 0.75, between about 0.1 and
0.5, between about 0.1 and 0.25), for example if the original
volume is 100 L and it is concentrated by 0.4 times, the final
volume will be 60 L.
[0023] After saccharification and optional other processing (e.g.,
fermentation and/or distillation), the sugar solutions can include
non-sugar suspended or dissolved solids present at concentrations
up to about 50 wt. %, for example between about 1 and 50 wt. %,
between about 2 and 40 wt. %, between about 3 and 25 wt. %, between
about 5 and 25 wt. %, between about 40 and 50 wt. %, between about
30 and 40 wt. %, between about 10 and 20 wt. %, between about 1 and
5 wt. %, between about 10 and 40 wt. %, less than about 50 wt. %,
less than about 40 wt. %, less than about 30 wt. %, less than about
20 wt. %, less than about 10 wt. %, less than about 5 wt. %, less
than about 1 wt. %, less than about 0.5 wt. %, less than about 0.01
wt. %. These solutions can have high turbidity, for example
measured to be at least about 5 Nephelometric Turbidity Units (NTU)
(e.g., at least about 10 NTU, at least about 50 NTU, at least about
100 NTU, at least about 200 NTU, at least about 300 NTU, at least
about 400 NTU and even greater than about 500 NTU). It is often
desirable to remove the un-dissolved solids and some of the
dissolved solids. The un-dissolved solids (e.g., residues) can be
removed via filtration (e.g., Rotary Vacuum Drum Filtration) and
centrifugation (e.g., continuous centrifugation). Some of the
dissolved impurities, may be precipitated out by treating the
solution with solvents such as methanol, ethanol, isopropanol,
acetone, ethyl ether and tetrahydrofuran, and then the precipitates
can be removed via filtration or centrifugation. In addition the
sugar solutions can have, for example, up to about 10 wt. % enzymes
(e.g., up to about 9 wt. %, up to about 8 wt. %, up to about 5 wt.
%, up to about 2 wt. %, up to about 1 wt. %, between about 0.1 and
5 wt. %, between about 1 wt. % and 5 wt. %, between about 2 wt. %
and 5 wt. %, between about 0.1 wt. % and 1 wt. %, between about
0.01 wt. % and 1 wt. %, between about 0.001 wt. % and 0.1 wt. %).
Enzymes (e.g., parts of enzymes, proteins), can be precipitated by
denaturing (e.g., adding an acid, a base, by heating and/or adding
solvents). Treatment with carbon dioxide and calcium hydroxide
(e.g., over liming) can also be effective in precipitating unwanted
compounds such as lignin derived products/impurities and enzymes
and proteins.
[0024] Preferably, solutions to be processed by SMB have less than
about 1 percent suspended solids (e.g. less than about 0.75%, less
than about 0.5%, less than about 0.4%, less than about 0.3%, less
than about 0.2%, less than about 0.15%, less than about 0.1%, less
than about 0.05%, less than about 0.025%, or even less than about
0.010%, between about 0.01-0.1%, between about 0.01 and 0.75%,
between about 0.01 and 0.5%, between about 0.01 and 0.25%, between
about 0.01 and 0.05%). The particle size and morphology of the
suspended solids (e.g., particles and agglomerates) can also vary
widely. For example the average particle size (e.g., determined by
light scattering) can be between about 0.05-50 microns (e.g., about
0.1-25 micron, 0.2-10 micron, 0.22-5 micron, 0.25-1 micron). After
removing the solids the solutions may have a turbidity of less than
about 50 NTU (e.g., less than about 10 NTU, less than about 5
NTU).
[0025] In addition to constituting unwanted components, some of the
organic and inorganic derived components produced from the biomass
processing described herein (e.g., saccharification, fermentation
and/or distillation) can include colored bodies that can impart
undesirable coloration to the final products. The molecular weights
and functional groups of the organic impurities can vary greatly,
for example, including carboxylate groups, ester groups, ketone
groups, unsaturated aliphatic groups, phenolic groups, amide
groups, amine groups, hydroxyl groups and/or aromatic groups (e.g.
aromatic chromophors). The colored impurities can include lignin
and lignin derived products, for example polyphenols, phenols,
phenol derivatives, aromatic compounds, soluble lignin fragments
and insoluble lignin fragments. Other colored impurities are
derived from the polysaccharide portions of the biomass. Some
colors can also be associated with colored inorganic materials
(e.g., iron). In the sugar industry, the colors that occur have
been classified into at least four groups; caramels, melanoids,
maillard reaction products and phenolic products. Often the amounts
of colored impurities is quite low, for example, less than 10 wt %
of the product (e.g., less than about 5 wt. %, less than about 1
wt. %, less than about 0.1 wt. %, less than 0.01 wt. %). The
solutions can be used directly in the SMB systems described herein
or the solutions can be partially or completely decolorized prior
to being used in the SMB systems. For example the colored
impurities can be filtered out of the solution, destroyed (e.g., by
chemical decomposition) and/or precipitated out of the solution.
Some possible color removing agents that can be used are powdered,
granular, extruded, bone char or bead activated carbon or carbon
black; styrenic resins (e.g., DOWEX.TM. SD-2), acrylic or magnetic
resins and decolorizing clays such as bentonite, attapulgite,
montmorillonite, hormite and combinations of these. Ions can be
removed, generally after removing the organic impurities. Ionic
compounds can be removed, for example, by using an ion exchange
resin and/or electrodialysis. After treating the solutions with
these color removing agents and optionally or alternatively
utilizing SMB, the color of the solution is less than about 200 as
measured by the Platinum-Cobalt method (ASTM Test Method D1209)
(e.g., less than 100, less than 50, less than about 40, less than
about 30, less than about 20, less than about 10, less than about 5
and even less than about 1). SMB can also be particularly
effective, in combination with or alternatively to the above
methods, for removing organic derived colored bodies from sugar
solutions.
[0026] SMB is a chromatographic technique based on a flow of liquid
(mobile phase) moving countercurrent to a constant flow of solid
(stationary phase) as shown in FIG. 1. Countercurrent flow enhances
the potential for the separation and, hence, makes the process more
efficient. It also allows a continuous flow of feed material to be
separated, which improves the throughput of the equipment compared
to traditional batch chromatography. Providing a constant flow of
solid is impractical in a production process. Therefore, the solid
instead is packed into high-pressure columns. As depicted in n FIG.
1, these columns are arranged in sequence e.g., a ring formation,
made up of four sections with one or more columns per section. Two
inlet streams (feed and eluent) and two outlets streams (extract
and raffinate) are directed in alternating order to and from the
column ring. Because the columns are not easily moved, the inlet
and outlet position is switched at regular time intervals in the
direction of the liquid flow, thus simulating countercurrent
movement of columns. The flow rates in Sections II and ill are
important because this is where the separation occurs. Sections and
IV handle the "cleaning" of the products. Mobile phase exiting
Section IV is directly recycled to Section I. The solid is
regenerated there by desorbing the more retained compound with a
high flow rate so the complete column can be "moved" into section
IV.
[0027] The stationary phase is disposed (e.g., packed in)
individual columns represented as columns 1 through 8 in FIG. 1.
The columns are connected in series and the stationary phase
comprises a resin capable of separating the sugar solution from the
impurities. Generally cross linked (e.g., with divinyl benzene)
strongly acidic cation exchanged resins (SAC resins) are utilized
in the form of beads. These resins contain sulfonic acid functional
groups wherein the protons have been completely or partially
exchanged with cations so that the resins include pendent cations.
Some cations include, for example, Li.sup.+, Na.sup.+, K.sup.+,
Cs.sup.+, Rb.sup.+, Ca.sup.2+, Mg.sup.2+, Sr.sup.2+, Al.sup.3+ or
combinations of these. The resins can have an ion exchange capacity
of greater than about 1.0 meq/mL (e.g., greater than about 1.1
meq/mL, greater than about 1.2 meq/mL, greater than about 1.3
meq/mL, greater than about 1.4 meq/mL, greater than about 1.6
meq/mL, greater than about 1.74 meq/mL, greater than about 2
meq/mL, or even greater than about 2.3 meq/mL. The beads can be
gels, for example with hydrogen bonded and free water in the narrow
channels and pores defined by the resins. The water content can be
between about 20 and 80 percent (e.g., between about 30 and 70%,
between about 40 and 70%, between about 30 and 60%, between about
40 and 60%, between about 57 and 67%, between about 35 and 45%,
between about 43 and 50%, between about 57 and 67%, between about
32 and 42%, between about 58 and 68%, between about 52 and 58%,
between about 46 and 52%, between about 37 and 43%, between about
53 and 59%, between about 45 and 52%, between about 45 and 55%,
between about 43 and 50%). Sugars can enter the narrow channels and
pores (e.g., dissolve or diffuse into the water in these pores and
channels) and can be bound (e.g., ligated, for ligands) to the
cations. The degree of binding can depend on the structure of the
sugar. For example, glucose and xylose generally binds more
strongly to calcium than fructose and therefor glucose and xylose
are retained more strongly by calcium exchanged SAC resins. Larger
molecules, such as oligomers and polymers (e.g., some of the
impurities previously discussed as well as disaccharides,
trisaccharides, oligosaccharides polysaccharides) are generally
excluded from the small pores and channels of the resins beads and
therefore elute much more quickly through the solid phase.
[0028] Some resins and their uses are described in the Appendix of
related PCT application PCT/US14/21638 filed Mar. 7, 2014, the full
disclosure of which is incorporated herein. For example resins that
can be utilized in the equipment, systems and processes describe
herein include DIAION.TM. SK1B, DIAION.TM. SK1B SK104, DIAION.TM.
SK1B SK110, DIAION.TM. SK1B SK112, DIAION.TM. SK1B PK208,
DIAION.TM. SK1B PK212, DIAION.TM. SK1B PK216, DIAION.TM. SK1B
PK220, DIAION.TM. SK1B PK228, DIAION.TM. SK1B UBK530, DIAION.TM.
SK1B UBK550, DIAION.TM. SK1B UBK535, DIAION.TM. SK1B UBK535,
DIAION.TM. SK1B UBK555, DIAION.TM. SK1B WK10, DIAION.TM. SK1B WK11,
DIAION.TM. SK1B WT100, DIAION.TM. SK1B WK40, DOWEX 88, DOWEX 22,
DOWEXMONOSPHERE.TM. 88, DOWEXMONOSPHERE.TM. 77, DOWEXMONOSPHERE.TM.
88 and DOWEX OPTIPORE SD-2
[0029] Beads can vary in size. Generally smaller beads can provide
a better separation of sugars from each other and from larger
molecules, but this separation comes at the expense of a larger
pressure drop. Therefore, careful selection of available/prepared
beads is necessary dependent on the specific sugar solution and
separations desired. For example beads can be generally spherical
in shape where the resins have an average diameter particle size
between about 100 micron to about 500 micron, such as between about
150 micron to about 400 micron, between about 200 micron to about
350 micron. Narrow bead size distribution can also be desirable,
for example, with bead sizes with about +100 and -100 microns in
diameter around the average particle size (e.g. +/-50 microns,
+/-40 microns, +/-40 microns, +/-30 microns, +/-20 microns, +/-15
microns, +/-10 microns), The density of the beads can be, for
example, between about 1 g/cc to about 1.75/cc (e.g., between about
1.1-1A g/cc, between about 1.2-1.35 g/cc).
[0030] The SAC resins can be utilized in a wide pH range (e.g., at
least between about 2 and 10). The SAC resins are also thermally
stable and can be utilized at least to about 140 deg. C. (e.g., up
to about 130 deg. C., up to about 120 deg. C.).
[0031] Saccharified and/or fermented feedstock (e.g. that can
include xylose, glucose, arabinose, glycerol, lactose, xylitol,
dissolved solids and alcohols such as ethanol, butanol) and eluents
(e.g., the mobile phase such water, acetonitrile, ether, hexanes,
acetone, methanol and tetrahydrofuran), are fed into the system as
indicated by "FEED" and "ELUENT" arrows in 1. There are two output
streams: an extract, which comprises the more retained component or
components, and a raffinate, which comprises the less retained
component or components. Separation occurs due to the different
interaction of the feed mixture components with the column
material. Components that interact more strongly with the column
material are retained more by the column material (e.g., have a
longer retention time) and are concentrated earlier in the column
so that they can be carried into the extract, whereas
weaker-interacting components move to the raffinate. Valves between
the columns (not shown in the figure) are systematically switched
open or closed at timed intervals (switch time) to introduce the
inlet streams (feed and eluent) and withdraw the outlet streams
(extract and raffinate) between the separation zones. The valve
switching is timed no as to simulate countercurrent movement of the
stationary phase. By adjusting the stream flow rates, the switch
time, the temperature, and the eluent composition, a cycle is
established in which feed and eluent are continuously added and
highly purified products are continuously recovered. Streams are
switched one column forward at each step of the cycle, timed to
collect pure extract and raffinate.
[0032] The countercurrent flow of stationary phase and mobile phase
created by SMB enables extremely efficient utilization of
stationary and mobile phases. In single column systems, separation
actually occurs in a small fraction of the column at any one time,
with the rest of the column performing no function other than
occupying solvent and broadening bands. With SMB, a series of small
columns is used instead of one large column. SMB provides
essentially an "infinite" column bed length without the costs
associated with obtaining, operating, and maintaining large single
columns.
[0033] In some embodiments, SMB can provide from the distillate
bottom of a saccharified and fermented biomass an extract composed
mostly of xylose (e.g. at least 70%, at least 75%, at least 80%, at
least 85%, at least 90%, at least 95%, at least 96%, at least 97%,
at least 98%, at least 99%, or even substantially 100% pure)
diluted in the eluent. The raffinate or waste stream can contain
approximately all (e.g. at least 95%, at least 96%, at least 97%,
at least 98%, at least 99%, or even substantially 100%) of the
undesired products (e.g., impurities), for example the impurities
can include aromatic chromophors, also diluted with the eluent. The
SMB process can be manipulated/modified by changing column
conditions to give a product stream/feed stream ratio of about 7.5,
5, 4.5, 4, 3.5, 3, 2.5, 2, 1.5, 1.3, 1.2 or even 1.1 and initial
waste stream/feed ratio of about 7.5, 5, 4.5, 4, 3.5, 3, 2.5, 2,
1.5, 1.3, 1.2 or even 1.1.
[0034] As previously discussed, in addition to sugars and products
such as alcohols, the solutions derived from biomass by the
processes such as saccharification and fermentation can include
solids, such as various suspended or dissolved compounds and/or
materials (e.g., solids). For example, solutions can include
enzymes (e.g., parts of enzymes, active enzymes, denatured
enzymes), amino acids, nutrients, live cells, dead cells, cellular
debris (e.g., lysed cells, yeast extract), acids, bases, salts
(e.g., halides, sulfates, and phosphates, alkali, alkali earth,
transition metal salts), partial hydrolysis products (e.g.,
cellulose and hemicellulose fragments), lignin, lignin residues,
inorganic solids (e.g., siliceous materials, clays, carbon black,
metals), remnants of saccharified and/or fermented biomass and
combinations thereof. In some cases, the enzymes can be present in
a functioning state and are denatured, e.g., by adding an acid, a
base, heating and/or adding a denaturing agent or proteases.
Denaturing the enzyme can facilitate its removal, e.g., by the
methods described herein. Some cellulolytic enzymes utilized for
saccharification of a biomass operate best in the acidic region,
e.g., between about pH 2 and 6 (e.g., between about 3 and 6,
between about, 4 and 6, between about 4 and 5). The solutions to be
purified (e.g., by SMB) can be used without pH adjustment or
optionally the pH can be adjusted up or down after
saccharification. In some embodiments the solution used in an SMB
system can therefore have pH values selected from a broad range.
Optionally, these impurities can be removed or decreased prior to
subjecting the biomass solution to SMB. In particular, it may be
beneficial to remove impurities (e.g., polymers, proteins,
precipitants) that can coat, plug, fill or otherwise hinder the
function of the columns. For example, the sugar solution may
undergo purification processes such as, rotary drum filtration,
filtration, over liming and or decolorization prior to being
subjected to an SMB process.
[0035] Another embodiment of the invention is described with
reference to FIG. 2. Processes for manufacturing sugar solutions
and products derived therefrom include, for example, optionally
mechanically treating a cellulosic and/or lignocellulosic
feedstock. Before and/or after this treatment, the feedstock can be
treated with another physical treatment (e.g., irradiation,
sonication, oxidation, steam explosion and/or pyrolysis), to
reduce, or further reduce its recalcitrance 212. A sugar solution
is formed by saccharifying 214 the reduced recalcitrance feedstock
by, for example, the addition of one or more enzymes, acids and
heat (e.g., in any order and/or combination). The sugar solution
from step 214 can then be processed using a separation process such
as SMB 216, to produce a raffinate stream 226 and an extract stream
224. SMB is a preferred method of producing an extract solution
that includes xylose and glucose. The raffinate includes color
bodies and ions. In some embodiments, additional steps such as ion
removing steps (e.g., using ion exchange columns) can be used, for
example, prior to SMB.
[0036] In yet another embodiment, SMB can be utilized sequentially,
as depicted by FIG. 3. Steps 212 and 214 have been described.
Saccharified material can be fermented 312, for example, using an
organism that selectively ferments one sugar, e.g., a glucose
fermenting organism. In a glucose fermentation step, the product of
the fermentation is a solution including the fermentation product,
xylose, ions and colored bodies. The fermented solution can then be
processed with a first separation process, for example, a first SMB
step 316. The first SMB processing produces an extract 324 stream,
for example a solution containing xylose. The first SMB processing
step also produces a raffinate 326 stream, for example, a solution
containing the fermentation product, ions and color bodies. The
raffinate stream 326 can be processed using a second separation
process 330, for example, a second SMB step. The second SMB step
can produce an extract 332, for example a solution containing the
fermentation product, and a raffinate 324. In some embodiments,
additional steps such as ion removing steps (e.g., using ion
exchange columns) can be used, for example, prior to an SMB. In
some embodiments the fermentation product can be an alcohol (e.g.,
ethanol, butanol) or and acid (e.g., butyric acid, L-lactic acid,
D-lactic acid).
Systems for Treating a Feedstock
[0037] Purification systems, methods and equipment (e.g., simulated
moving bed chromatography) can be applied to materials that have
been processed as described above and also as described anywhere
herein.
[0038] For example, processes for the conversion of a feedstocks to
sugars and other products can include, for example, optionally
physically pre-treating the feedstock, e.g., to reduce its size,
before and/or after this treatment, optionally treating the
feedstock to reduce its recalcitrance (e.g., by irradiation), and
saccharifying the feedstock to form a sugar solution (e.g., as
previously described and reiterated and expanded here).
Saccharification can be performed by mixing a dispersion of the
feedstock in a liquid medium, e.g., water with an enzyme, as will
be discussed in detail below. During or after saccharification, the
mixture (e.g., if saccharification is to be partially or completely
performed en route) or solution can be transported, e.g., by
pipeline, railcar, truck or barge, to a manufacturing plant. At the
plant, the solution can be bioprocessed, e.g., fermented, to
produce a desired product or intermediate, which can then be
processed further, e.g., by distillation and simulated moving bed
chromatography. The individual processing steps, materials used and
examples of products and intermediates that may be formed will be
described in detail below. Therefore, in addition to these methods,
purification systems, methods and equipment (e.g., simulated moving
bed chromatography) can be applied, for example, as an additional
processing step.
Radiation Treatment
[0039] The feedstock can be treated with radiation to modify its
structure to reduce its recalcitrance. Such treatment can, for
example, reduce the average molecular weight of the feedstock,
change the crystalline structure of the feedstock, and/or increase
the surface area and/or porosity of the feedstock. Radiation can be
by, for example electron beam, ion beam, 100 nm to 28 nm
ultraviolet (UV) light, gamma or X-ray radiation. Radiation
treatments and systems for treatments are discussed in U.S. Pat.
No. 8,142,620 and U.S. patent application Ser. No. 12/417,731, the
entire disclosures of which are incorporated herein by
reference.
[0040] Each form of radiation ionizes the biomass via particular
interactions, as determined by the energy of the radiation. Heavy
charged particles primarily ionize matter via Coulomb scattering;
furthermore, these interactions produce energetic electrons that
may further ionize matter. Alpha particles are identical to the
nucleus of a helium atom and are produced by the alpha decay of
various radioactive nuclei, such as isotopes of bismuth, polonium,
astatine, radon, francium, radium, several actinides, such as
actinium, thorium, uranium, neptunium, curium, californium,
americium, and plutonium. Electrons interact via Coulomb scattering
and bremsstrahlung radiation produced by changes in the velocity of
electrons.
[0041] When particles are utilized, they can be neutral
(uncharged), positively charged or negatively charged. When
charged, the charged particles can bear a single positive or
negative charge, or multiple charges, e.g., one, two, three or even
four or more charges. In instances in which chain scission is
desired to change the molecular structure of the carbohydrate
containing material, positively charged particles may be desirable,
in part, due to their acidic nature. When particles are utilized,
the particles can have the mass of a resting electron, or greater,
e.g., 500, 1000, 1500, or 2000 or more times the mass of a resting
electron. For example, the particles can have a mass of from about
1 atomic unit to about 150 atomic units, e.g., from about 1 atomic
unit to about 50 atomic units, or from about 1 to about 25, e.g.,
1, 2, 3, 4, 5, 10, 12 or 15 atomic units.
[0042] Gamma radiation has the advantage of a significant
penetration depth into a variety of material in the sample.
[0043] In embodiments in which the irradiating is performed with
electromagnetic radiation, the electromagnetic radiation can have,
e.g., energy per photon (in electron volts) of greater than
10.sup.2 eV, e.g., greater than 10.sup.3, 10.sup.4, 10.sup.5,
10.sup.6, or even greater than 10.sup.7 eV. In some embodiments,
the electromagnetic radiation has energy per photon of between
10.sup.4 and 10.sup.7, e.g., between 10.sup.5 and 10.sup.6 eV. The
electromagnetic radiation can have a frequency of, e.g., greater
than 10.sup.16 Hz, greater than 10.sup.17 Hz, 10.sup.18, 10.sup.19,
10.sup.20, or even greater than 10.sup.21 Hz. In some embodiments,
the electromagnetic radiation has a frequency of between 10.sup.18
and 10.sup.22 Hz, e.g., between 10.sup.19 to 10.sup.21 Hz.
[0044] Electron bombardment may be performed using an electron beam
device that has a nominal energy of less than 10 MeV, e.g., less
than 7 MeV, less than 5 MeV, or less than 2 MeV, e.g., from about
0.5 to 1.5 MeV, from about 0.8 to 1.8 MeV, or from about 0.7 to 1
MeV. In some implementations the nominal energy is about 500 to 800
keV.
[0045] The electron beam may have a relatively high total beam
power (the combined beam power of all accelerating heads, or, if
multiple accelerators are used, of all accelerators and all heads),
e.g., at least 25 kW, e.g., at least 30, 40, 50, 60, 65, 70, 80,
100, 125, or 150 kW. In some cases, the power is even as high as
500 kW, 750 kW, or even 1000 kW or more. In some cases the electron
beam has a beam power of 1200 kW or more, e.g., 1400, 1600, 1800,
or even 3000 kW.
[0046] This high total beam power is usually achieved by utilizing
multiple accelerating heads. For example, the electron beam device
may include two, four, or more accelerating heads. The use of
multiple heads, each of which has a relatively low beam power,
prevents excessive temperature rise in the material, thereby
preventing burning of the material, and also increases the
uniformity of the dose through the thickness of the layer of
material.
[0047] It is generally preferred that the bed of biomass material
has a relatively uniform thickness. In some embodiments the
thickness is less than about 1 inch (e.g., less than about 0.75
inches, less than about 0.5 inches, less than about 0.25 inches,
less than about 0.1 inches, between about 0.1 and 1 inch, between
about 0.2 and 0.3 inches).
[0048] It is desirable to treat the material as quickly as
possible. In general, it is preferred that treatment be performed
at a dose rate of greater than about 0.25 Mrad per second, e.g.,
greater than about 0.5, 0.75, 1, 1.5, 2, 5, 7, 10, 12, 15, or even
greater than about 20 Mrad per second, e.g., about 0.25 to 2 Mrad
per second. Higher dose rates allow a higher throughput for a
target (e.g., the desired) dose. Higher dose rates generally
require higher line speeds, to avoid thermal decomposition of the
material. In one implementation, the accelerator is set for 3 MeV,
50 mA beam current, and the line speed is 24 feet/minute, for a
sample thickness of about 20 mm (e.g., comminuted corn cob material
with a bulk density of 0.5 g/cm.sup.3).
[0049] In some embodiments, electron bombardment is performed until
the material receives a total dose of at least 0.1 Mrad, 0.25 Mrad,
1 Mrad, 5 Mrad, e.g., at least 10, 20, 30 or at least 40 Mrad. In
some embodiments, the treatment is performed until the material
receives a dose of from about 10 Mrad to about 50 Mrad, e.g., from
about 20 Mrad to about 40 Mrad, or from about 25 Mrad to about 30
Mrad. In some implementations, a total dose of 25 to 35 Mrad is
preferred, applied ideally over a couple of passes, e.g., at 5
Mrad/pass with each pass being applied for about one second.
Cooling methods, systems and equipment can be used before, during,
after and in between radiations, for example utilizing a cooling
screw conveyor and/or a cooled vibratory conveyor.
[0050] Using multiple heads as discussed above, the material can be
treated in multiple passes, for example, two passes at 10 to 20
Mrad/pass, e.g., 12 to 18 Mrad/pass, separated by a few seconds of
cool-down, or three passes of 7 to 12 Mrad/pass, e.g., 5 to 20
Mrad/pass, 10 to 40 Mrad/pass, 9 to 11 Mrad/pass. As discussed
herein, treating the material with several relatively low doses,
rather than one high dose, tends to prevent overheating of the
material and also increases dose uniformity through the thickness
of the material. In some implementations, the material is stirred
or otherwise mixed during or after each pass and then smoothed into
a uniform layer again before the next pass, to further enhance
treatment uniformity.
[0051] In some embodiments, electrons are accelerated to, for
example, a speed of greater than 75 percent of the speed of light,
e.g., greater than 85, 90, 95, or 99 percent of the speed of
light.
[0052] In some embodiments, any processing described herein occurs
on lignocellulosic material that remains dry as acquired or that
has been dried, e.g., using heat and/or reduced pressure. For
example, in some embodiments, the cellulosic and/or lignocellulosic
material has less than about 25 wt. % retained water, measured at
25.degree. C. and at fifty percent relative humidity (e.g., less
than about 20 wt. %, less than about 15 wt. %, less than about 14
wt. %, less than about 13 wt. %, less than about 12 wt. %, less
than about 10 wt. %, less than about 9 wt. %, less than about 8 wt.
%, less than about 7 wt. %, less than about 6 wt. %, less than
about 5 wt. %, less than about 4 wt. %, less than about 3 wt. %,
less than about 2 wt. %, less than about 1 wt. %, or less than
about 0.5 wt. %.
[0053] In some embodiments, two or more ionizing sources can be
used, such as two or more electron sources. For example, samples
can be treated, in any order, with a beam of electrons, followed by
gamma radiation and UV light having wavelengths from about 100 nm
to about 280 nm. In some embodiments, samples are treated with
three ionizing radiation sources, such as a beam of electrons,
gamma radiation, and energetic UV light. The biomass is conveyed
through the treatment zone where it can be bombarded with
electrons.
[0054] It may be advantageous to repeat the treatment to more
thoroughly reduce the recalcitrance of the biomass and/or further
modify the biomass. In particular the process parameters can be
adjusted after a first (e.g., second, third, fourth or more) pass
depending on the recalcitrance of the material. In some
embodiments, a conveyor can be used which includes a circular
system where the biomass is conveyed multiple times through the
various processes described above. In some other embodiments
multiple treatment devices (e.g., electron beam generators) are
used to treat the biomass multiple (e.g., 2, 3, 4 or more) times.
In yet other embodiments, a single electron beam generator may be
the source of multiple beams (e.g., 2, 3, 4 or more beams) that can
be used for treatment of the biomass.
[0055] The effectiveness in changing the molecular/supermolecular
structure and/or reducing the recalcitrance of the
carbohydrate-containing biomass depends on the electron energy used
and the dose applied, while exposure time depends on the power and
dose. In some embodiments, the dose rate and total dose are
adjusted so as not to destroy (e.g., char or burn) the biomass
material. For example, the carbohydrates should not be damaged in
the processing so that they can be released from the biomass
intact, e.g. as monomeric sugars.
[0056] In some embodiments, the treatment (with any electron source
or a combination of sources) is performed until the material
receives a dose of at least about 0.05 Mrad, e.g., at least about
0.1, 0.25, 0.5, 0.75, 1.0, 2.5, 5.0, 7.5, 10.0, 15, 20, 25, 30, 40,
50, 60, 70, 80, 90, 100, 125, 150, 175, or 200 Mrad. In some
embodiments, the treatment is performed until the material receives
a dose of between 0.1-100 Mrad, 1-200, 5-200, 10-200, 5-150, 50-150
Mrad, 5-100, 5-50, 5-40, 10-50, 10-75, 15-50, 20-35 Mrad.
[0057] In some embodiments, relatively low doses of radiation are
utilized, e.g., to increase the molecular weight of a cellulosic or
lignocellulosic material (with any radiation source or a
combination of sources described herein). For example, a dose of at
least about 0.05 Mrad, e.g., at least about 0.1 Mrad or at least
about 0.25, 0.5, 0.75. 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, or at
least about 5.0 Mrad. In some embodiments, the irradiation is
performed until the material receives a dose of between 0.1Mrad and
2.0 Mrad, e.g., between 0.5 Mrad and 4.0 Mrad or between 1.0 Mrad
and 3.0 Mrad.
[0058] It also can be desirable to irradiate from multiple
directions, simultaneously or sequentially, in order to achieve a
desired degree of penetration of radiation into the material. For
example, depending on the density and moisture content of the
material, such as wood, and the type of radiation source used
(e.g., gamma or electron beam), the maximum penetration of
radiation into the material may be only about 0.75 inch. In such
cases, a thicker section (up to 1.5 inch) can be irradiated by
first irradiating the material from one side, and then turning the
material over and irradiating from the other side. Irradiation from
multiple directions can be particularly useful with electron beam
radiation, which irradiates faster than gamma radiation but
typically does not achieve as great a penetration depth.
Radiation Opaque Materials
[0059] The invention can include processing a material in a vault
and/or bunker that is constructed using radiation opaque materials.
In some implementations, the radiation opaque materials are
selected to be capable of shielding the components from X-rays with
high energy (short wavelength), which can penetrate many materials.
One important factor in designing a radiation shielding enclosure
is the attenuation length of the materials used, which will
determine the required thickness for a particular material, blend
of materials, or layered structure. The attenuation length is the
penetration distance at which the radiation is reduced to
approximately 1/e (e=Euler's number) times that of the incident
radiation. Although virtually all materials are radiation opaque if
thick enough, materials containing a high compositional percentage
(e.g., density) of elements that have a high Z value (atomic
number) have a shorter radiation attenuation length and thus if
such materials are used a thinner, lighter shielding can be
provided. Examples of high Z value materials that are used in
radiation shielding are tantalum and lead. Another important
parameter in radiation shielding is the halving distance, which is
the thickness of a particular material that will reduce gamma ray
intensity by 50%. As an example for X-ray radiation with an energy
of 0.1 MeV the halving thickness is about 15.1 mm for concrete and
about 2.7 mm for lead, while with an X-ray energy of 1 MeV the
halving thickness for concrete is about 44.45 mm and for lead is
about 7.9 mm. Radiation opaque materials can be materials that are
thick or thin so long as they can reduce the radiation that passes
through to the other side. Thus, if it is desired that a particular
enclosure have a low wall thickness, e.g., for light weight or due
to size constraints, the material chosen should have a sufficient Z
value and/or attenuation length so that its halving length is less
than or equal to the desired wall thickness of the enclosure.
[0060] In some cases, the radiation opaque material may be a
layered material, for example having a layer of a higher Z value
material, to provide good shielding, and a layer of a lower Z value
material to provide other properties (e.g., structural integrity,
impact resistance, etc.). In some cases, the layered material may
be a "graded-Z" laminate, e.g., including a laminate in which the
layers provide a gradient from high-Z through successively lower-Z
elements. As previously described herein, in some cases the
radiation opaque materials can be interlocking blocks, for example,
lead and/or concrete blocks can be supplied by NELCO Worldwide
(Burlington, Mass.), and reconfigurable vaults can be utilized.
[0061] A radiation opaque material can reduce the radiation passing
through a structure (e.g., a wall, door, ceiling, enclosure, a
series of these or combinations of these) formed of the material by
about at least about 10%, (e.g., at least about 20%, at least about
30%, at least about 40%, at least about 50%, at least about 60%, at
least about 70%, at least about 80%, at least about 90%, at least
about 95%, at least about 96%, at least about 97%, at least about
98%, at least about 99%, at least about 99.9%, at least about
99.99%, at least about 99.999%) as compared to the incident
radiation. Therefore, an enclosure made of a radiation opaque
material can reduce the exposure of equipment/system/components by
the same amount. Radiation opaque materials can include stainless
steel, metals with Z values above 25 (e.g., lead, iron), concrete,
dirt, sand and combinations thereof. Radiation opaque materials can
include a barrier in the direction of the incident radiation of at
least about 1 mm (e.g., 5 mm, 10 mm, 5 cm, 10 cm, 100 cm, 1 m and
even at least about 10 m).
Radiation Sources
[0062] The type of radiation determines the kinds of radiation
sources used as well as the radiation devices and associated
equipment. The methods, systems and equipment described herein, for
example for treating materials with radiation, can utilized sources
as described herein as well as any other useful source.
[0063] Sources of gamma rays include radioactive nuclei, such as
isotopes of cobalt, calcium, technetium, chromium, gallium, indium,
iodine, iron, krypton, samarium, selenium, sodium, thallium, and
xenon.
[0064] Sources of X-rays include electron beam collision with metal
targets, such as tungsten or molybdenum or alloys, or compact light
sources, such as those produced commercially by Lyncean.
[0065] Alpha particles are identical to the nucleus of a helium
atom and are produced by the alpha decay of various radioactive
nuclei, such as isotopes of bismuth, polonium, astatine, radon,
francium, radium, several actinides, such as actinium, thorium,
uranium, neptunium, curium, californium, americium, and
plutonium.
[0066] Sources for ultraviolet radiation include deuterium or
cadmium lamps.
[0067] Sources for infrared radiation include sapphire, zinc, or
selenide window ceramic lamps.
[0068] Sources for microwaves include klystrons, Slevin type RF
sources, or atom beam sources that employ hydrogen, oxygen, or
nitrogen gases.
[0069] Accelerators used to accelerate the particles can be
electrostatic DC, electrodynamic DC, RF linear, magnetic induction
linear or continuous wave. For example, cyclotron type accelerators
are available from IBA, Belgium, such as the RHODOTRON.TM. system,
while DC type accelerators are available from RDI, now IBA
Industrial, such as the DYNAMITRON.RTM.. Ions and ion accelerators
are discussed in Introductory Nuclear Physics, Kenneth S. Krane,
John Wiley & Sons, Inc. (1988), Krsto Prelec, FIZIKA B 6 (1997)
4, 177-206, Chu, William T., "Overview of Light-Ion Beam Therapy",
Columbus-Ohio, ICRU-IAEA Meeting, 18-20 Mar. 2006, Iwata, Y. et
al., "Alternating-Phase-Focused IH-DTL for Heavy-Ion Medical
Accelerators", Proceedings of EPAC 2006, Edinburgh, Scotland, and
Leitner, C. M. et al., "Status of the Superconducting ECR Ion
Source Venus", Proceedings of EPAC 2000, Vienna, Austria.
[0070] Electrons may be produced by radioactive nuclei that undergo
beta decay, such as isotopes of iodine, cesium, technetium, and
iridium. Alternatively, an electron gun can be used as an electron
source via thermionic emission and accelerated through an
accelerating potential. An electron gun generates electrons, which
are then accelerated through a large potential (e.g., greater than
about 500 thousand, greater than about 1 million, greater than
about 2 million, greater than about 5 million, greater than about 6
million, greater than about 7 million, greater than about 8
million, greater than about 9 million, or even greater than 10
million volts) and then scanned magnetically in the x-y plane,
where the electrons are initially accelerated in the z direction
down the accelerator tube and extracted through a foil window.
Scanning the electron beams is useful for increasing the
irradiation surface when irradiating materials, e.g., a biomass,
that is conveyed through the scanned beam. Scanning the electron
beam also distributes the thermal load homogenously on the window
and helps reduce the foil window rupture due to local heating by
the electron beam. Window foil rupture is a cause of significant
down-time due to subsequent necessary repairs and re-starting the
electron gun.
[0071] Various other irradiating devices may be used in the methods
disclosed herein, including field ionization sources, electrostatic
ion separators, field ionization generators, thermionic emission
sources, microwave discharge ion sources, recirculating or static
accelerators, dynamic linear accelerators, van de Graaff
accelerators, and folded tandem accelerators. Such devices are
disclosed, for example, in U.S. Pat. No. 7,931,784 to Medoff, the
complete disclosure of which is incorporated herein by
reference.
[0072] A beam of electrons can be used as the radiation source. A
beam of electrons has the advantages of high dose rates (e.g., 1,
5, or even 10 Mrad per second), high throughput, less containment,
and less confinement equipment. Electron beams can also have high
electrical efficiency (e.g., 80%), allowing for lower energy usage
relative to other radiation methods, which can translate into a
lower cost of operation and lower greenhouse gas emissions
corresponding to the smaller amount of energy used. Electron beams
can be generated, e.g., by electrostatic generators, cascade
generators, transformer generators, low energy accelerators with a
scanning system, low energy accelerators with a linear cathode,
linear accelerators, and pulsed accelerators.
[0073] Electrons can also be more efficient at causing changes in
the molecular structure of carbohydrate-containing materials, for
example, by the mechanism of chain scission. In addition, electrons
having energies of 0.5-10 MeV can penetrate low density materials,
such as the biomass materials described herein, e.g., materials
having a bulk density of less than 0.5 g/cm.sup.3, and a depth of
0.3-10 cm. Electrons as an ionizing radiation source can be useful,
e.g., for relatively thin piles, layers or beds of materials, e.g.,
less than about 0.5 inch, e.g., less than about 0.4 inch, 0.3 inch,
0.25 inch, or less than about 0.1 inch. In some embodiments, the
energy of each electron of the electron beam is from about 0.3 MeV
to about 2.0 MeV (million electron volts), e.g., from about 0.5 MeV
to about 1.5 MeV, or from about 0.7 MeV to about 1.25 MeV. Methods
of irradiating materials are discussed in U.S. Pat. App. Pub.
2012/0100577 A1, filed Oct. 18, 2011, the entire disclosure of
which is herein incorporated by reference.
[0074] Electron beam irradiation devices may be procured
commercially or built. For example elements or components such
inductors, capacitors, casings, power sources, cables, wiring,
voltage control systems, current control elements, insulating
material, microcontrollers and cooling equipment can be purchased
and assembled into a device. Optionally, a commercial device can be
modified and/or adapted. For example, devices and components can be
purchased from any of the commercial sources described herein
including Ion Beam Applications (Louvain-la-Neuve, Belgium), Wasik
Associates Inc. (Dracut, Mass.), NHV Corporation (Japan), the Titan
Corporation (San Diego, Calif.), Vivirad High Voltage Corp
(Billerica, Mass.) and/or Budker Laboratories (Russia). Typical
electron energies can be 0.5 MeV, 1 MeV, 2 MeV, 4.5 MeV, 7.5 MeV,
or 10 MeV. Typical electron beam irradiation device power can be 1
kW, 5 kW, 10 kW, 20 kW, 50 kW, 60 kW, 70 kW, 80 kW, 90 kW, 100 kW,
125 kW, 150 kW, 175 kW, 200 kW, 250 kW, 300 kW, 350 kW, 400 kW, 450
kW, 500 kW, 600 kW, 700 kW, 800 kW, 900 kW or even 1000 kW.
Accelerators that can be used include NHV irradiators medium energy
series EPS-500 (e.g., 500 kV accelerator voltage and 65, 100 or 150
mA beam current), EPS-800 (e.g., 800 kV accelerator voltage and 65
or 100 mA beam current), or EPS-1000 (e.g., 1000 kV accelerator
voltage and 65 or 100 mA beam current). Also, accelerators from
NHV's high energy series can be used such as EPS-1500 (e.g., 1500
kV accelerator voltage and 65 mA beam current), EPS-2000 (e.g.,
2000 kV accelerator voltage and 50 mA beam current), EPS-3000
(e.g., 3000 kV accelerator voltage and 50 mA beam current) and
EPS-5000 (e.g., 5000 and 30 mA beam current).
[0075] Tradeoffs in considering electron beam irradiation device
power specifications include cost to operate, capital costs,
depreciation, and device footprint. Tradeoffs in considering
exposure dose levels of electron beam irradiation would be energy
costs and environment, safety, and health (ESH) concerns.
Typically, generators are housed in a vault, e.g., of lead or
concrete, especially for production from X-rays that are generated
in the process. Tradeoffs in considering electron energies include
energy costs.
[0076] The electron beam irradiation device can produce either a
fixed beam or a scanning beam. A scanning beam may be advantageous
with large scan sweep length and high scan speeds, as this would
effectively replace a large, fixed beam width. Further, available
sweep widths of 0.5 m, 1 m, 2 m or more are available. The scanning
beam is preferred in most embodiments describe herein because of
the larger scan width and reduced possibility of local heating and
failure of the windows.
Electron Guns--Windows
[0077] The extraction system for an electron accelerator can
include two window foils. The cooling gas in the two foil window
extraction system can be a purge gas or a mixture, for example air,
or a pure gas. In one embodiment the gas is an inert gas such as
nitrogen, argon, helium and or carbon dioxide. It is preferred to
use a gas rather than a liquid since energy losses to the electron
beam are minimized. Mixtures of pure gas can also be used, either
pre-mixed or mixed in line prior to impinging on the windows or in
the space between the windows. The cooling gas can be cooled, for
example, by using a heat exchange system (e.g., a chiller) and/or
by using boil off from a condensed gas (e.g., liquid nitrogen,
liquid helium). Window foils are described in PCT/US2013/64332
filed Oct. 10, 2013 the full disclosure of which is incorporated by
reference herein.
Heating and Throughput During Radiation Treatment
[0078] Several processes can occur in biomass when electrons from
an electron beam interact with matter in inelastic collisions. For
example, ionization of the material, chain scission of polymers in
the material, cross linking of polymers in the material, oxidation
of the material, generation of X-rays ("Bremsstrahlung") and
vibrational excitation of molecules (e.g., phonon generation).
Without being bound to a particular mechanism, the reduction in
recalcitrance can be due to several of these inelastic collision
effects, for example ionization, chain scission of polymers,
oxidation and phonon generation. Some of the effects (e.g.,
especially X-ray generation), necessitate shielding and engineering
barriers, for example, enclosing the irradiation processes in a
concrete (or other radiation opaque material) vault. Another effect
of irradiation, vibrational excitation, is equivalent to heating up
the sample. Heating the sample by irradiation can help in
recalcitrance reduction, but excessive heating can destroy the
material, as will be explained below.
[0079] The adiabatic temperature rise (AT) from adsorption of
ionizing radiation is given by the equation: .DELTA.T=D/Cp: where D
is the average dose in kGy, Cp is the heat capacity in J/g .degree.
C., and .DELTA.T is the change in temperature in .degree. C. A
typical dry biomass material will have a heat capacity close to 2.
Wet biomass will have a higher heat capacity dependent on the
amount of water since the heat capacity of water is very high (4.19
J/g .degree. C.). Metals have much lower heat capacities, for
example 304 stainless steel has a heat capacity of 0.5 J/g .degree.
C. The temperature change due to the instant adsorption of
radiation in a biomass and stainless steel for various doses of
radiation is shown below. At the higher temperatures biomass will
decompose causing extreme deviation from the estimated changes in
temperature. Calculated Temperature increase for biomass and
stainless steel.
TABLE-US-00001 Dose (Mrad) Estimated Biomass .DELTA.T (.degree. C.)
Steel .DELTA.T (.degree. C.) 10 50 200 50 250 (Decomposition) 1000
100 500 (Decomposition) 2000 150 750 (Decomposition) 3000 200 1000
(Decomposition) 4000
[0080] High temperatures can destroy and or modify the biopolymers
in biomass so that the polymers (e.g., cellulose) are unsuitable
for further processing. A biomass subjected to high temperatures
can become dark, sticky and give off odors indicating
decomposition. The stickiness can even make the material hard to
convey. The odors can be unpleasant and be a safety issue. In fact,
keeping the biomass below about 200.degree. C. has been found to be
beneficial in the processes described herein (e.g., below about
190.degree. C., below about 180.degree. C., below about 170.degree.
C., below about 160.degree. C., below about 150.degree. C., below
about 140.degree. C., below about 130.degree. C., below about
120.degree. C., below about 110.degree. C., between about
60.degree. C. and 180.degree. C., between about 60.degree. C. and
160.degree. C., between about 60.degree. C. and 150.degree. C.,
between about 60.degree. C. and 140.degree. C., between about
60.degree. C. and 130.degree. C., between about 60.degree. C. and
120.degree. C., between about 80.degree. C. and 180.degree. C.,
between about 100.degree. C. and 180.degree. C., between about
120.degree. C. and 180.degree. C., between about 140.degree. C. and
180.degree. C., between about 160.degree. C. and 180.degree. C.,
between about 100.degree. C. and 140.degree. C., between about
80.degree. C. and 120.degree. C.).
[0081] It has been found that irradiation above about 10 Mrad is
desirable for the processes described herein (e.g., reduction of
recalcitrance). A high throughput is also desirable so that the
irradiation does not become a bottle neck in processing the
biomass. The treatment is governed by a Dose rate equation:
M=FP/Dtime, where M is the mass of irradiated material (kg), F is
the fraction of power that is adsorbed (unit less), P is the
emitted power (kW=Voltage in MeV.times.Current in mA), time is the
treatment time (sec) and D is the adsorbed dose (kGy). In an
exemplary process where the fraction of adsorbed power is fixed,
the Power emitted is constant and a set dosage is desired, the
throughput (e.g., M, the biomass processed) can be increased by
increasing the irradiation time. However, increasing the
irradiation time without allowing the material to cool, can
excessively heat the material as exemplified by the calculations
shown above. Since biomass has a low thermal conductivity (less
than about 0.1 Wm.sup.-1K.sup.-1), heat dissipation is slow,
unlike, for example, metals (greater than about 10
Wm.sup.-1K.sup.-1) which can dissipate energy quickly as long as
there is a heat sink to transfer the energy to.
Electron Guns--Beam Stops
[0082] In some embodiments the systems and methods include a beam
stop (e.g., a shutter). For example, the beam stop can be used to
quickly stop or reduce the irradiation of material without powering
down the electron beam device. Alternatively the beam stop can be
used while powering up the electron beam, e.g., the beam stop can
stop the electron beam until a beam current of a desired level is
achieved. The beam stop can be placed between the primary foil
window and a secondary foil window. For example, the beam stop can
be mounted so that it is movable, that is, so that it can be moved
into and out of the beam path. Even partial coverage of the beam
can be used, for example, to control the dose of irradiation. The
beam stop can be mounted to the floor, to a conveyor for the
biomass, to a wall, to the radiation device (e.g., at the scan
horn), or to any structural support. Preferably the beam stop is
fixed in relation to the scan horn so that the beam can be
effectively controlled by the beam stop. The beam stop can
incorporate a hinge, a rail, wheels, slots, or other means allowing
for its operation in moving into and out of the beam. The beam stop
can be made of any material that will stop at least 5% of the
electrons, e.g., at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, at
least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or
even about 100% of the electrons.
[0083] The beam stop can be made of a metal including, but not
limited to, stainless steel, lead, iron, molybdenum, silver, gold,
titanium, aluminum, tin, or alloys of these, or laminates (layered
materials) made with such metals (e.g., metal-coated ceramic,
metal-coated polymer, metal-coated composite, multilayered metal
materials).
[0084] The beam stop can be cooled, for example, with a cooling
fluid such as an aqueous solution or a gas. The beam stop can be
partially or completely hollow, for example with cavities. Interior
spaces of the beam stop can be used for cooling fluids and gases.
The beam stop can be of any shape, including flat, curved, round,
oval, square, rectangular, beveled and wedged shapes.
[0085] The beam stop can have perforations so as to allow some
electrons through, thus controlling (e.g., reducing) the levels of
radiation across the whole area of the window, or in specific
regions of the window. The beam stop can be a mesh formed, for
example, from fibers or wires. Multiple beam stops can be used,
together or independently, to control the irradiation. The beam
stop can be remotely controlled, e.g., by radio signal or hard
wired to a motor for moving the beam into or out of position.
Beam Dumps
[0086] The embodiments disclosed herein can also include a beam
dump when utilizing a radiation treatment. A beam dump's purpose is
to safely absorb a beam of charged particles. Like a beam stop, a
beam dump can be used to block the beam of charged particles.
However, a beam dump is much more robust than a beam stop, and is
intended to block the full power of the electron beam for an
extended period of time. They are often used to block the beam as
the accelerator is powering up.
[0087] Beam dumps are also designed to accommodate the heat
generated by such beams, and are usually made from materials such
as copper, aluminum, carbon, beryllium, tungsten, or mercury. Beam
dumps can be cooled, for example, using a cooling fluid that can be
in thermal contact with the beam dump.
Biomass Materials
[0088] Lignocellulosic materials include, but are not limited to,
wood, particle board, forestry wastes (e.g., sawdust, aspen wood,
wood chips), grasses, (e.g., switchgrass, miscanthus, cord grass,
reed canary grass), grain residues, (e.g., rice hulls, oat hulls,
wheat chaff, barley hulls), agricultural waste (e.g., silage,
canola straw, wheat straw, barley straw, oat straw, rice straw,
jute, hemp, flax, bamboo, sisal, abaca, corn cobs, corn stover,
soybean stover, corn fiber, alfalfa, hay, coconut hair), sugar
processing residues (e.g., bagasse, beet pulp, agave bagasse),
algae, seaweed, manure, sewage, and mixtures of any of these.
[0089] In some cases, the lignocellulosic material includes
corncobs. Ground or hammermilled corncobs can be spread in a layer
of relatively uniform thickness for irradiation, and after
irradiation are easy to disperse in the medium for further
processing. To facilitate harvest and collection, in some cases the
entire corn plant is used, including the corn stalk, corn kernels,
and in some cases even the root system of the plant.
[0090] Advantageously, no additional nutrients (other than a
nitrogen source, e.g., urea or ammonia) are required during
fermentation of corncobs or cellulosic or lignocellulosic materials
containing significant amounts of corncobs.
[0091] Corncobs, before and after comminution, are also easier to
convey and disperse, and have a lesser tendency to form explosive
mixtures in air than other cellulosic or lignocellulosic materials
such as hay and grasses.
[0092] Cellulosic materials include, for example, paper, paper
products, paper waste, paper pulp, pigmented papers, loaded papers,
coated papers, filled papers, magazines, printed matter (e.g.,
books, catalogs, manuals, labels, calendars, greeting cards,
brochures, prospectuses, newsprint), printer paper, polycoated
paper, card stock, cardboard, paperboard, materials having a high
.alpha.-cellulose content such as cotton, and mixtures of any of
these. For example paper products as described in U.S. application
Ser. No. 13/396,365 ("Magazine Feedstocks" by Medoff et al., filed
Feb. 14, 2012), the full disclosure of which is incorporated herein
by reference.
[0093] Cellulosic materials can also include lignocellulosic
materials which have been partially or fully de-lignified.
[0094] In some instances other biomass materials can be utilized,
for example starchy materials. Starchy materials include starch
itself, e.g., corn starch, wheat starch, potato starch or rice
starch, a derivative of starch, or a material that includes starch,
such as an edible food product or a crop. For example, the starchy
material can be arracacha, buckwheat, banana, barley, cassava,
kudzu, oca, sago, sorghum, regular household potatoes, sweet
potato, taro, yams, or one or more beans, such as favas, lentils or
peas. Blends of any two or more starchy materials are also starchy
materials. Mixtures of starchy, cellulosic and or lignocellulosic
materials can also be used. For example, a biomass can be an entire
plant, a part of a plant or different parts of a plant, e.g., a
wheat plant, cotton plant, a corn plant, rice plant or a tree. The
starchy materials can be treated by any of the methods described
herein.
[0095] Microbial materials that can be used as feedstock can
include, but are not limited to, any naturally occurring or
genetically modified microorganism or organism that contains or is
capable of providing a source of carbohydrates (e.g., cellulose),
for example, protists, e.g., animal protists (e.g., protozoa such
as flagellates, amoeboids, ciliates, and sporozoa) and plant
protists (e.g., algae such alveolates, chlorarachniophytes,
cryptomonads, euglenids, glaucophytes, haptophytes, red algae,
stramenopiles, and viridaeplantae). Other examples include seaweed,
plankton (e.g., macroplankton, mesoplankton, microplankton,
nanoplankton, picoplankton, and femptoplankton), phytoplankton,
bacteria (e.g., gram positive bacteria, gram negative bacteria, and
extremophiles), yeast and/or mixtures of these. In some instances,
microbial biomass can be obtained from natural sources, e.g., the
ocean, lakes, bodies of water, e.g., salt water or fresh water, or
on land. Alternatively or in addition, microbial biomass can be
obtained from culture systems, e.g., large scale dry and wet
culture and fermentation systems.
[0096] In other embodiments, the biomass materials, such as
cellulosic, starchy and lignocellulosic feedstock materials, can be
obtained from transgenic microorganisms and plants that have been
modified with respect to a wild type variety. Such modifications
may be, for example, through the iterative steps of selection and
breeding to obtain desired traits in a plant. Furthermore, the
plants can have had genetic material removed, modified, silenced
and/or added with respect to the wild type variety. For example,
genetically modified plants can be produced by recombinant DNA
methods, where genetic modifications include introducing or
modifying specific genes from parental varieties, or, for example,
by using transgenic breeding wherein a specific gene or genes are
introduced to a plant from a different species of plant and/or
bacteria. Another way to create genetic variation is through
mutation breeding wherein new alleles are artificially created from
endogenous genes. The artificial genes can be created by a variety
of ways including treating the plant or seeds with, for example,
chemical mutagens (e.g., using alkylating agents, epoxides,
alkaloids, peroxides, formaldehyde), irradiation (e.g., X-rays,
gamma rays, neutrons, beta particles, alpha particles, protons,
deuterons, UV radiation) and temperature shocking or other external
stressing and subsequent selection techniques. Other methods of
providing modified genes is through error prone PCR and DNA
shuffling followed by insertion of the desired modified DNA into
the desired plant or seed. Methods of introducing the desired
genetic variation in the seed or plant include, for example, the
use of a bacterial carrier, biolistics, calcium phosphate
precipitation, electroporation, gene splicing, gene silencing,
lipofection, microinjection and viral carriers. Additional
genetically modified materials have been described in U.S.
application Ser. No. 13/396,369 filed Feb. 14, 2012 the full
disclosure of which is incorporated herein by reference. Any of the
methods described herein can be practiced with mixtures of any
biomass materials described herein.
Biomass Material Preparation--Mechanical Treatments
[0097] The biomass can be in a dry form, for example with less than
about 35% moisture content (e.g., less than about 20%, less than
about 15%, less than about 10% less than about 5%, less than about
4%, less than about 3%, less than about 2% or even less than about
1%). The biomass can also be delivered in a wet state, for example
as a wet solid, a slurry or a suspension with at least about 10 wt
% solids (e.g., at least about 20 wt. %, at least about 30 wt. %,
at least about 40 wt. %, at least about 50 wt. %, at least about 60
wt. %, at least about 70 wt. %).
[0098] The processes disclosed herein can utilize low bulk density
materials, for example cellulosic or lignocellulosic feedstocks
that have been physically pretreated to have a bulk density of less
than about 0.75 g/cm.sup.3, e.g., less than about 0.7, 0.65, 0.60,
0.50, 0.35, 0.25, 0.20, 0.15, 0.10, 0.05 or less, e.g., less than
about 0.025 g/cm.sup.3. Bulk density is determined using ASTM
D1895B. Briefly, the method involves filling a measuring cylinder
of known volume with a sample and obtaining a weight of the sample.
The bulk density is calculated by dividing the weight of the sample
in grams by the known volume of the cylinder in cubic centimeters.
If desired, low bulk density materials can be densified, for
example, by methods described in U.S. Pat. No. 7,971,809 to Medoff,
the full disclosure of which is hereby incorporated by
reference.
[0099] In some cases, the pre-treatment processing includes
screening of the biomass material. Screening can be through a mesh
or perforated plate with a desired opening size, for example, less
than about 6.35 mm (1/4 inch, 0.25 inch), (e.g., less than about
3.18 mm (1/8 inch, 0.125 inch), less than about 1.59 mm ( 1/16
inch, 0.0625 inch), is less than about 0.79 mm ( 1/32 inch, 0.03125
inch), e.g., less than about 0.51 mm ( 1/50 inch, 0.02000 inch),
less than about 0.40 mm ( 1/64 inch, 0.015625 inch), less than
about 0.23 mm (0.009 inch), less than about 0.20 mm ( 1/128 inch,
0.0078125 inch), less than about 0.18 mm (0.007 inch), less than
about 0.13 mm (0.005 inch), or even less than about 0.10 mm ( 1/256
inch, 0.00390625 inch)). In one configuration the desired biomass
falls through the perforations or screen and thus biomass larger
than the perforations or screen are not irradiated. These larger
materials can be re-processed, for example by comminuting, or they
can simply be removed from processing. In another configuration
material that is larger than the perforations is irradiated and the
smaller material is removed by the screening process or recycled.
In this kind of a configuration, the conveyor itself (for example a
part of the conveyor) can be perforated or made with a mesh. For
example, in one particular embodiment the biomass material may be
wet and the perforations or mesh allow water to drain away from the
biomass before irradiation.
[0100] Screening of material can also be by a manual method, for
example by an operator or mechanoid (e.g., a robot equipped with a
color, reflectivity or other sensor) that removes unwanted
material. Screening can also be by magnetic screening wherein a
magnet is disposed near the conveyed material and the magnetic
material is removed magnetically.
[0101] Optional pre-treatment processing can include heating the
material. For example a portion of a conveyor conveying the
material or other material can be sent through a heated zone. The
heated zone can be created, for example, by IR radiation,
microwaves, combustion (e.g., gas, coal, oil, biomass), resistive
heating and/or inductive coils. The heat can be applied from at
least one side or more than one side, can be continuous or periodic
and can be for only a portion of the material or all the material.
For example, a portion of the conveying trough can be heated by use
of a heating jacket. Heating can be, for example, for the purpose
of drying the material. In the case of drying the material, this
can also be facilitated, with or without heating, by the movement
of a gas (e.g., air, oxygen, nitrogen, He, CO.sub.2, Argon) over
and/or through the biomass as it is being conveyed.
[0102] Optionally, pre-treatment processing can include cooling the
material. Cooling material is described in U.S. Pat. No. 7,900,857
to Medoff, the disclosure of which in incorporated herein by
reference. For example, cooling can be by supplying a cooling
fluid, for example water (e.g., with glycerol), or nitrogen (e.g.,
liquid nitrogen) to the bottom of the conveying trough.
Alternatively, a cooling gas, for example, chilled nitrogen can be
blown over the biomass materials or under the conveying system.
[0103] Another optional pre-treatment processing method can include
adding a material to the biomass or other feedstocks. The
additional material can be added by, for example, by showering,
sprinkling and or pouring the material onto the biomass as it is
conveyed. Materials that can be added include, for example, metals,
ceramics and/or ions as described in U.S. Pat. App. Pub.
2010/0105119 A1 (filed Oct. 26, 2009) and U.S. Pat. App. Pub.
2010/0159569 A1 (filed Dec. 16, 2009), the entire disclosures of
which are incorporated herein by reference. Optional materials that
can be added include acids and bases. Other materials that can be
added are oxidants (e.g., peroxides, chlorates), polymers,
polymerizable monomers (e.g., containing unsaturated bonds), water,
catalysts, enzymes and/or organisms. Materials can be added, for
example, in pure form, as a solution in a solvent (e.g., water or
an organic solvent) and/or as a solution. In some cases the solvent
is volatile and can be made to evaporate e.g., by heating and/or
blowing gas as previously described. The added material may form a
uniform coating on the biomass or be a homogeneous mixture of
different components (e.g., biomass and additional material). The
added material can modulate the subsequent irradiation step by
increasing the efficiency of the irradiation, damping the
irradiation or changing the effect of the irradiation (e.g., from
electron beams to X-rays or heat). The method may have no impact on
the irradiation but may be useful for further downstream
processing. The added material may help in conveying the material,
for example, by lowering dust levels.
[0104] Biomass can be delivered to a conveyor (e.g., vibratory
conveyors used in the vaults herein described) by a belt conveyor,
a pneumatic conveyor, a screw conveyor, a hopper, a pipe, manually
or by a combination of these. The biomass can, for example, be
dropped, poured and/or placed onto the conveyor by any of these
methods. In some embodiments the material is delivered to the
conveyor using an enclosed material distribution system to help
maintain a low oxygen atmosphere and/or control dust and fines.
Lofted or air suspended biomass fines and dust are undesirable
because these can form an explosion hazard or damage the window
foils of an electron gun (if such a device is used for treating the
material).
[0105] The material can be leveled to form a uniform thickness
between about 0.0312 and 5 inches (e.g., between about 0.0625 and
2.000 inches, between about 0.125 and 1 inches, between about 0.125
and 0.5 inches, between about 0.3 and 0.9 inches, between about 0.2
and 0.5 inches between about 0.25 and 1.0 inches, between about
0.25 and 0.5 inches, 0.100+/-0.025 inches, 0.150+/-0.025 inches,
0.200+/-0.025 inches, 0.250+/-0.025 inches, 0.300+/-0.025 inches,
0.350+/-0.025 inches, 0.400+/-0.025 inches, 0.450+/-0.025 inches,
0.500+/-0.025 inches, 0.550+/-0.025 inches, 0.600+/-0.025 inches,
0.700+/-0.025 inches, 0.750+/-0.025 inches, 0.800+/-0.025 inches,
0.850+/-0.025 inches, 0.900+/-0.025 inches, 0.900+/-0.025
inches.
[0106] Generally, it is preferred to convey the material as quickly
as possible through the electron beam to maximize throughput. For
example the material can be conveyed at rates of at least 1 ft/min,
e.g., at least 2 ft/min, at least 3 ft/min, at least 4 ft/min, at
least 5 ft/min, at least 10 ft/min, at least 15 ft/min, 20, 25, 30,
35, 40, 45, 50 ft/min. The rate of conveying is related to the beam
current, for example, for a 1/4 inch thick biomass and 100 mA, the
conveyor can move at about 20 ft/min to provide a useful
irradiation dosage, at 50 mA the conveyor can move at about 10
ft/min to provide approximately the same irradiation dosage.
[0107] After the biomass material has been conveyed through the
radiation zone, optional post-treatment processing can be done. The
optional post-treatment processing can, for example, be a process
described with respect to the pre-irradiation processing. For
example, the biomass can be screened, heated, cooled, and/or
combined with additives. Uniquely to post-irradiation, quenching of
the radicals can occur, for example, quenching of radicals by the
addition of fluids or gases (e.g., oxygen, nitrous oxide, ammonia
and/or liquids), using pressure, heat, and/or the addition of
radical scavengers. For example, the biomass can be conveyed out of
the enclosed conveyor and exposed to a gas (e.g., oxygen) where it
is quenched, forming carboxylated groups. In one embodiment the
biomass is exposed during irradiation to the reactive gas or fluid.
Quenching of biomass that has been irradiated is described in U.S.
Pat. No. 8,083,906 to Medoff, the entire disclosure of which is
incorporate herein by reference.
[0108] If desired, one or more mechanical treatments can be used in
addition to irradiation to further reduce the recalcitrance of the
carbohydrate-containing material. These processes can be applied
before, during and or after irradiation.
[0109] In some cases, the mechanical treatment may include an
initial preparation of the feedstock as received, e.g., size
reduction of materials, such as by comminution, e.g., cutting,
grinding, shearing, pulverizing or chopping. For example, in some
cases, loose feedstock (e.g., recycled paper, starchy materials, or
switchgrass) is prepared by shearing or shredding. Mechanical
treatment may reduce the bulk density of the
carbohydrate-containing material, increase the surface area of the
carbohydrate-containing material and/or decrease one or more
dimensions of the carbohydrate-containing material.
[0110] Alternatively, or in addition, the feedstock material can be
treated with another treatment, for example chemical treatments,
such as with an acid (HCl, H.sub.2SO.sub.4, H.sub.3PO.sub.4), a
base (e.g., KOH and NaOH), a chemical oxidant (e.g., peroxides,
chlorates, and/or ozone), irradiation, steam explosion, pyrolysis,
sonication, oxidation, chemical treatment. The treatments can be in
any order and in any sequence and combinations. For example, the
feedstock material can first be physically treated by one or more
treatment methods, e.g., chemical treatment including and in
combination with acid hydrolysis (e.g., utilizing HCl,
H.sub.2SO.sub.4, H.sub.3PO.sub.4), radiation, sonication,
oxidation, pyrolysis or steam explosion, and then mechanically
treated. This sequence can be advantageous since materials treated
by one or more of the other treatments, e.g., irradiation or
pyrolysis, tend to be more brittle and, therefore, it may be easier
to further change the structure of the material by mechanical
treatment. As another example, a feedstock material can be conveyed
through ionizing radiation using a conveyor as described herein and
then mechanically treated. Chemical treatment can remove some or
all of the lignin (for example, chemical pulping) and can partially
or completely hydrolyze the material. The methods also can be used
with pre-hydrolyzed material. The methods also can be used with
material that has not been pre hydrolyzed The methods can be used
with mixtures of hydrolyzed and non-hydrolyzed materials, for
example with about 50% or more non-hydrolyzed material, with about
60% or more non-hydrolyzed material, with about 70% or more
non-hydrolyzed material, with about 80% or more non-hydrolyzed
material or even with 90% or more non-hydrolyzed material.
[0111] In addition to size reduction, which can be performed
initially and/or later in processing, mechanical treatment can also
be advantageous for "opening up," "stressing," breaking or
shattering the carbohydrate-containing materials, making the
cellulose of the materials more susceptible to chain scission
and/or disruption of crystalline structure during the physical
treatment.
[0112] Methods of mechanically treating the carbohydrate-containing
material include, for example, milling or grinding. Milling may be
performed using, for example, a hammer mill, ball mill, colloid
mill, conical or cone mill, disk mill, edge mill, Wiley mill, grist
mill or other mill. Grinding may be performed using, for example, a
cutting/impact type grinder. Some exemplary grinders include stone
grinders, pin grinders, coffee grinders, and bun grinders. Grinding
or milling may be provided, for example, by a reciprocating pin or
other element, as is the case in a pin mill. Other mechanical
treatment methods include mechanical ripping or tearing, other
methods that apply pressure to the fibers, and air attrition
milling. Suitable mechanical treatments further include any other
technique that continues the disruption of the internal structure
of the material that was initiated by the previous processing
steps.
[0113] Mechanical feed preparation systems can be configured to
produce streams with specific characteristics such as, for example,
specific maximum sizes, specific length-to-width, or specific
surface areas ratios. Physical preparation can increase the rate of
reactions, improve the movement of material on a conveyor, improve
the irradiation profile of the material, improve the radiation
uniformity of the material, or reduce the processing time required
by opening up the materials and making them more accessible to
processes and/or reagents, such as reagents in a solution.
[0114] The bulk density of feedstocks can be controlled (e.g.,
increased). In some situations, it can be desirable to prepare a
low bulk density material, e.g., by densifying the material (e.g.,
densification can make it easier and less costly to transport to
another site) and then reverting the material to a lower bulk
density state (e.g., after transport). The material can be
densified, for example from less than about 0.2 g/cc to more than
about 0.9 g/cc (e.g., less than about 0.3 to more than about 0.5
g/cc, less than about 0.3 to more than about 0.9 g/cc, less than
about 0.5 to more than about 0.9 g/cc, less than about 0.3 to more
than about 0.8 g/cc, less than about 0.2 to more than about 0.5
g/cc). For example, the material can be densified by the methods
and equipment disclosed in U.S. Pat. No. 7,932,065 to Medoff and
International Publication No. WO 2008/073186 (which was filed Oct.
26, 2007, was published in English, and which designated the United
States), the full disclosures of which are incorporated herein by
reference. Densified materials can be processed by any of the
methods described herein, or any material processed by any of the
methods described herein can be subsequently densified.
[0115] In some embodiments, the material to be processed is in the
form of a fibrous material that includes fibers provided by
shearing a fiber source. For example, the shearing can be performed
with a rotary knife cutter.
[0116] For example, a fiber source, e.g., that is recalcitrant or
that has had its recalcitrance level reduced, can be sheared, e.g.,
in a rotary knife cutter, to provide a first fibrous material. The
first fibrous material is passed through a first screen, e.g.,
having an average opening size of 1.59 mm or less ( 1/16 inch,
0.0625 inch), provide a second fibrous material. If desired, the
fiber source can be cut prior to the shearing, e.g., with a
shredder. For example, when a paper is used as the fiber source,
the paper can be first cut into strips that are, e.g., 1/4- to
1/2-inch wide, using a shredder, e.g., a counter-rotating screw
shredder, such as those manufactured by Munson (Utica, N.Y.). As an
alternative to shredding, the paper can be reduced in size by
cutting to a desired size using a guillotine cutter. For example,
the guillotine cutter can be used to cut the paper into sheets that
are, e.g., 10 inches wide by 12 inches long.
[0117] In some embodiments, the shearing of the fiber source and
the passing of the resulting first fibrous material through a first
screen are performed concurrently. The shearing and the passing can
also be performed in a batch-type process.
[0118] For example, a rotary knife cutter can be used to
concurrently shear the fiber source and screen the first fibrous
material. A rotary knife cutter includes a hopper that can be
loaded with a shredded fiber source prepared by shredding a fiber
source.
[0119] In some implementations, the feedstock is physically treated
prior to saccharification and/or fermentation. Physical treatment
processes can include one or more of any of those described herein,
such as mechanical treatment, chemical treatment, irradiation,
sonication, oxidation, pyrolysis or steam explosion. Treatment
methods can be used in combinations of two, three, four, or even
all of these technologies (in any order). When more than one
treatment method is used, the methods can be applied at the same
time or at different times. Other processes that change a molecular
structure of a biomass feedstock may also be used, alone or in
combination with the processes disclosed herein.
[0120] Mechanical treatments that may be used, and the
characteristics of the mechanically treated carbohydrate-containing
materials, are described in further detail in U.S. Pat. App. Pub.
2012/0100577 A1, filed Oct. 18, 2011, the full disclosure of which
is hereby incorporated herein by reference.
Sonication, Pyrolysis, Oxidation, Steam Explosion
[0121] If desired, one or more sonication, pyrolysis, oxidative, or
steam explosion processes can be used instead of or in addition to
irradiation to reduce or further reduce the recalcitrance of the
carbohydrate-containing material. For example, these processes can
be applied before, during and or after irradiation. These processes
are described in detail in U.S. Pat. No. 7,932,065 to Medoff, the
full disclosure of which is incorporated herein by reference.
Intermediates and Products
[0122] Using the processes described herein, the biomass material
can be converted to one or more products, such as energy, fuels,
foods and materials. For example, intermediates and products such
as organic acids, salts of organic acids, anhydrides, esters of
organic acids and fuels, e.g., fuels for internal combustion
engines or feedstocks for fuel cells. Systems and processes are
described herein that can use as feedstock cellulosic and/or
lignocellulosic materials that are readily available, but often can
be difficult to process, e.g., municipal waste streams and waste
paper streams, such as streams that include newspaper, Kraft paper,
corrugated paper or mixtures of these.
[0123] Specific examples of products include, but are not limited
to, hydrogen, sugars (e.g., glucose, xylose, arabinose, mannose,
galactose, fructose, disaccharides, oligosaccharides and
polysaccharides), alcohols (e.g., monohydric alcohols or dihydric
alcohols, such as ethanol, n-propanol, isobutanol, sec-butanol,
tert-butanol or n-butanol), hydrated or hydrous alcohols (e.g.,
containing greater than 10%, 20%, 30% or even greater than 40%
water), biodiesel, organic acids, hydrocarbons (e.g., methane,
ethane, propane, isobutene, pentane, n-hexane, biodiesel,
bio-gasoline and mixtures thereof), co-products (e.g., proteins,
such as cellulolytic proteins (enzymes) or single cell proteins),
and mixtures of any of these in any combination or relative
concentration, and optionally in combination with any additives
(e.g., fuel additives). Other examples include carboxylic acids,
salts of a carboxylic acid, a mixture of carboxylic acids and salts
of carboxylic acids and esters of carboxylic acids (e.g., methyl,
ethyl and n-propyl esters), ketones (e.g., acetone), aldehydes
(e.g., acetaldehyde), alpha and beta unsaturated acids (e.g.,
acrylic acid) and olefins (e.g., ethylene). Other alcohols and
alcohol derivatives include propanol, propylene glycol,
1,4-butanediol, 1,3-propanediol, sugar alcohols (e.g., erythritol,
glycol, glycerol, sorbitol threitol, arabitol, ribitol, mannitol,
dulcitol, fucitol, iditol, isomalt, maltitol, lactitol, xylitol and
other polyols), and methyl or ethyl esters of any of these
alcohols. Other products include methyl acrylate,
methylmethacrylate, D-lactic acid, L-Lactic acid, pyruvic acid,
poly lactic acid, citric acid, formic acid, acetic acid, propionic
acid, butyric acid, succinic acid, valeric acid, caproic acid,
3-hydroxypropionic acid, palmitic acid, stearic acid, oxalic acid,
malonic acid, glutaric acid, oleic acid, linoleic acid, glycolic
acid, gamma-hydroxybutyric acid, and mixtures thereof, salts of any
of these acids, mixtures of any of the acids and their respective
salts.
[0124] Any combination of the above products with each other,
and/or of the above products with other products, which other
products may be made by the processes described herein or
otherwise, may be packaged together and sold as products. The
products may be combined, e.g., mixed, blended or co-dissolved, or
may simply be packaged or sold together.
[0125] Any of the products or combinations of products described
herein may be sanitized or sterilized prior to selling the
products, e.g., after purification or isolation or even after
packaging, to neutralize one or more potentially undesirable
contaminants that could be present in the product(s). Such
sanitation can be done with electron bombardment, for example, be
at a dosage of less than about 20 Mrad, e.g., from about 0.1 to 15
Mrad, from about 0.5 to 7 Mrad, or from about 1 to 3 Mrad.
[0126] The processes described herein can produce various
by-product streams useful for generating steam and electricity to
be used in other parts of the plant (co-generation) or sold on the
open market. For example, steam generated from burning by-product
streams can be used in a distillation process. As another example,
electricity generated from burning by-product streams can be used
to power electron beam generators used in pretreatment.
[0127] The by-products used to generate steam and electricity are
derived from a number of sources throughout the process. For
example, anaerobic digestion of wastewater can produce a biogas
high in methane and a small amount of waste biomass (sludge). As
another example, post-saccharification and/or post-distillate
solids (e.g., unconverted lignin, cellulose, and hemicellulose
remaining from the pretreatment and primary processes) can be used,
e.g., burned, as a fuel.
[0128] Other intermediates and products, including food and
pharmaceutical products, are described in U.S. Pat. App. Pub.
2010/0124583 A1, published May 20, 2010, to Medoff, the full
disclosure of which is hereby incorporated by reference herein.
Lignin Derived Products
[0129] The spent biomass (e.g., spent lignocellulosic material)
from lignocellulosic processing by the methods described are
expected to have a high lignin content and in addition to being
useful for producing energy through combustion in a Co-Generation
plant, may have uses as other valuable products. For example, the
lignin can be used as captured as a plastic, or it can be
synthetically upgraded to other plastics. In some instances, it can
also be converted to lignosulfonates, which can be utilized as
binders, dispersants, emulsifiers or sequestrants.
[0130] When used as a binder, the lignin or a lignosulfonate can,
e.g., be utilized in coal briquettes, in ceramics, for binding
carbon black, for binding fertilizers and herbicides, as a dust
suppressant, in the making of plywood and particle board, for
binding animal feeds, as a binder for fiberglass, as a binder in
linoleum paste and as a soil stabilizer.
[0131] When used as a dispersant, the lignin or lignosulfonates can
be used, for example in, concrete mixes, clay and ceramics, dyes
and pigments, leather tanning and in gypsum board.
[0132] When used as an emulsifier, the lignin or lignosulfonates
can be used, e.g., in asphalt, pigments and dyes, pesticides and
wax emulsions.
[0133] As a sequestrant, the lignin or lignosulfonates can be used,
e.g., in micro-nutrient systems, cleaning compounds and water
treatment systems, e.g., for boiler and cooling systems.
[0134] For energy production lignin generally has a higher energy
content than holocellulose (cellulose and hemicellulose) since it
contains more carbon than homocellulose. For example, dry lignin
can have an energy content of between about 11,000 and 12,500 BTU
per pound, compared to 7,000 an 8,000 BTU per pound of
holocellulose. As such, lignin can be densified and converted into
briquettes and pellets for burning. For example, the lignin can be
converted into pellets by any method described herein. For a slower
burning pellet or briquette, the lignin can be crosslinked, such as
applying a radiation dose of between about 0.5 Mrad and 5 Mrad.
Crosslinking can make a slower burning form factor. The form
factor, such as a pellet or briquette, can be converted to a
"synthetic coal" or charcoal by pyrolyzing in the absence of air,
e.g., at between 400 and 950.degree. C. Prior to pyrolyzing, it can
be desirable to crosslink the lignin to maintain structural
integrity.
Saccharification
[0135] In order to convert the feedstock to a form that can be
readily processed, the glucan- or xylan-containing cellulose in the
feedstock can be hydrolyzed to low molecular weight carbohydrates,
such as sugars, by a saccharifying agent, e.g., an enzyme or acid,
a process referred to as saccharification. The low molecular weight
carbohydrates can then be used, for example, in an existing
manufacturing plant, such as a single cell protein plant, an enzyme
manufacturing plant, or a fuel plant, e.g., an ethanol
manufacturing facility.
[0136] The feedstock can be hydrolyzed using an enzyme, e.g., by
combining the materials and the enzyme in a solvent, e.g., in an
aqueous solution.
[0137] Alternatively, the enzymes can be supplied by organisms that
break down biomass, such as the cellulose and/or the lignin
portions of the biomass, contain or manufacture various
cellulolytic enzymes (cellulases), ligninases or various small
molecule biomass-degrading metabolites. These enzymes may be a
complex of enzymes that act synergistically to degrade crystalline
cellulose or the lignin portions of biomass. Examples of
cellulolytic enzymes include: endoglucanases, cellobiohydrolases,
and cellobiases (beta-glucosidases).
[0138] During saccharification a cellulosic substrate can be
initially hydrolyzed by endoglucanases at random locations
producing oligomeric intermediates. These intermediates are then
substrates for exo-splitting glucanases such as cellobiohydrolase
to produce cellobiose from the ends of the cellulose polymer.
Cellobiose is a water-soluble 1,4-linked dimer of glucose. Finally,
cellobiase cleaves cellobiose to yield glucose. The efficiency
(e.g., time to hydrolyze and/or completeness of hydrolysis) of this
process depends on the recalcitrance of the cellulosic
material.
[0139] Therefore, the treated biomass materials can be
saccharified, generally by combining the material and a cellulase
enzyme in a fluid medium, e.g., an aqueous solution. In some cases,
the material is boiled, steeped, or cooked in hot water prior to
saccharification, as described in U.S. Pat. App. Pub. 2012/0100577
A1 by Medoff and Masterman, published on Apr. 26, 2012, the entire
contents of which are incorporated herein.
[0140] The saccharification process can be partially or completely
performed in a tank (e.g., a tank having a volume of at least 4000,
40,000, or 500,000 L) in a manufacturing plant, and/or can be
partially or completely performed in transit, e.g., in a rail car,
tanker truck, or in a supertanker or the hold of a ship. The time
required for complete saccharification will depend on the process
conditions and the carbohydrate-containing material and enzyme
used. If saccharification is performed in a manufacturing plant
under controlled conditions, the cellulose may be substantially
entirely converted to sugar, e.g., glucose in about 12-96 hours. If
saccharification is performed partially or completely in transit,
saccharification may take longer.
[0141] It is generally preferred that the tank contents be mixed
during saccharification, e.g., using jet mixing as described in
International App. No. PCT/US2010/035331, filed May 18, 2010, which
was published in English as WO 2010/135380 and designated the
United States, the full disclosure of which is incorporated by
reference herein.
[0142] The addition of surfactants can enhance the rate of
saccharification. Examples of surfactants include non-ionic
surfactants, such as a Tween.RTM. 20 or Tween.RTM. 80 polyethylene
glycol surfactants, ionic surfactants, or amphoteric
surfactants.
[0143] It is generally preferred that the concentration of the
sugar solution resulting from saccharification be relatively high,
e.g., greater than 40%, or greater than 50, 60, 70, 80, 90 or even
greater than 95% by weight. Water may be removed, e.g., by
evaporation, to increase the concentration of the sugar solution.
This reduces the volume to be shipped, and also inhibits microbial
growth in the solution.
[0144] Alternatively, sugar solutions of lower concentrations may
be used, in which case it may be desirable to add an antimicrobial
additive, e.g., a broad spectrum antibiotic, in a low
concentration, e.g., 50 to 150 ppm. Other suitable antibiotics
include amphotericin B, ampicillin, chloramphenicol, ciprofloxacin,
gentamicin, hygromycin B, kanamycin, neomycin, penicillin,
puromycin, streptomycin. Antibiotics will inhibit growth of
microorganisms during transport and storage, and can be used at
appropriate concentrations, e.g., between 15 and 1000 ppm by
weight, e.g., between 25 and 500 ppm, or between 50 and 150 ppm. If
desired, an antibiotic can be included even if the sugar
concentration is relatively high. Alternatively, other additives
with anti-microbial of preservative properties may be used.
Preferably the antimicrobial additive(s) are food-grade.
[0145] A relatively high concentration solution can be obtained by
limiting the amount of water added to the carbohydrate-containing
material with the enzyme. The concentration can be controlled,
e.g., by controlling how much saccharification takes place. For
example, concentration can be increased by adding more
carbohydrate-containing material to the solution. In order to keep
the sugar that is being produced in solution, a surfactant can be
added, e.g., one of those discussed above. Solubility can also be
increased by increasing the temperature of the solution. For
example, the solution can be maintained at a temperature of
40-50.degree. C., 60-80.degree. C., or even higher.
Saccharifying Agents
[0146] Suitable cellulolytic enzymes include cellulases from
species in the genera Bacillus, Coprinus, Myceliophthora,
Cephalosporium, Scytalidium, Penicillium, Aspergillus, Pseudomonas,
Humicola, Fusarium, Thielavia, Acremonium, Chrysosporium and
Trichoderma, especially those produced by a strain selected from
the species Aspergillus (see, e.g., EP Pub. No. 0 458 162),
Humicola insolens (reclassified as Scytalidium thermophilum, see,
e.g., U.S. Pat. No. 4,435,307), Coprinus cinereus, Fusarium
oxysporum, Myceliophthora thermophila, Meripilus giganteus,
Thielavia terrestris, Acremonium sp. (including, but not limited
to, A. persicinum, A. acremonium, A. brachypenium, A.
dichromosporum, A. obclavatum, A. pinkertoniae, A. roseogriseum, A.
incoloratum, and A. furatum). Preferred strains include Humicola
insolens DSM 1800, Fusarium oxysporum DSM 2672, Myceliophthora
thermophila CBS 117.65, Cephalosporium sp. RYM-202, Acremonium sp.
CBS 478.94, Acremonium sp. CBS 265.95, Acremonium persicinum CBS
169.65, Acremonium acremonium AHU 9519, Cephalosporium sp. CBS
535.71, Acremonium brachypenium CBS 866.73, Acremonium
dichromosporum CBS 683.73, Acremonium obclavatum CBS 311.74,
Acremonium pinkertoniae CBS 157.70, Acremonium roseogriseum CBS
134.56, Acremonium incoloratum CBS 146.62, and Acremonium furatum
CBS 299.70H. Cellulolytic enzymes may also be obtained from
Chrysosporium, preferably a strain of Chrysosporium lucknowense.
Additional strains that can be used include, but are not limited
to, Trichoderma (particularly T. viride, T. reesei, and T.
koningii), alkalophilic Bacillus (see, for example, U.S. Pat. No.
3,844,890 and EP Pub. No. 0 458 162), and Streptomyces (see, e.g.,
EP Pub. No. 0 458 162).
[0147] In addition to or in combination to enzymes, acids, bases
and other chemicals (e.g., oxidants) can be utilized to saccharify
lignocellulosic and cellulosic materials. These can be used in any
combination or sequence (e.g., before, after and/or during addition
of an enzyme). For example, strong mineral acids can be utilized
(e.g. HCl, H.sub.2SO.sub.4, H.sub.3PO.sub.4) and strong bases
(e.g., NaOH, KOH).
Sugars
[0148] In the processes described herein, for example after
saccharification, sugars (e.g., glucose and xylose) can be
isolated. For example, sugars can be isolated by precipitation,
crystallization, chromatography (e.g., simulated moving bed
chromatography as described herein, high pressure chromatography),
centrifugation, extraction, any other isolation method known in the
art, and combinations thereof.
Hydrogenation and Other Chemical Transformations
[0149] The processes described herein can include hydrogenation.
For example glucose and xylose can be hydrogenated to sorbitol and
xylitol respectively. Hydrogenation can be accomplished by use of a
catalyst (e.g., Pt/gamma-Al.sub.2O.sub.3, Ru/C, Raney Nickel, or
other catalysts know in the art) in combination with H.sub.2 under
high pressure (e.g., 10 to 12000 psi). Other types of chemical
transformation of the products from the processes described herein
can be used, for example, production of organic sugar derived
products such (e.g., furfural and furfural-derived products).
Chemical transformations of sugar derived products are described in
U.S. Ser. No. 13/934,704 filed Jul. 3, 2013, the entire disclosure
of which is incorporated herein by reference.
Fermentation
[0150] Yeast and Zymomonas bacteria, for example, can be used for
fermentation or conversion of sugar(s) to alcohol(s). Other
microorganisms are discussed below. The optimum pH for
fermentations is about pH 4 to 7. For example, the optimum pH for
yeast is from about pH 4 to 5, while the optimum pH for Zymomonas
is from about pH 5 to 6. Typical fermentation times are about 24 to
168 hours (e.g., 24 to 96 hrs) with temperatures in the range of
20.degree. C. to 40.degree. C. (e.g., 26.degree. C. to 40.degree.
C.); however, thermophilic microorganisms prefer higher
temperatures.
[0151] In some embodiments, e.g., when anaerobic organisms are
used, at least a portion of the fermentation is conducted in the
absence of oxygen, e.g., under a blanket of an inert gas such as
N.sub.2, Ar, He, CO.sub.2 or mixtures thereof. Additionally, the
mixture may have a constant purge of an inert gas flowing through
the tank during part of or all of the fermentation. In some cases,
anaerobic conditions can be achieved or maintained by carbon
dioxide production during the fermentation and no additional inert
gas is needed.
[0152] In some embodiments, all or a portion of the fermentation
process can be interrupted before the low molecular weight sugar is
completely converted to a product (e.g., ethanol). The intermediate
fermentation products include sugar and carbohydrates in high
concentrations. The sugars and carbohydrates can be isolated via
any means known in the art. These intermediate fermentation
products can be used in preparation of food for human or animal
consumption. Additionally or alternatively, the intermediate
fermentation products can be ground to a fine particle size in a
stainless-steel laboratory mill to produce a flour-like substance.
Jet mixing may be used during fermentation, and in some cases
saccharification and fermentation are performed in the same
tank.
[0153] Nutrients for the microorganisms may be added during
saccharification and/or fermentation, for example the food-based
nutrient packages described in U.S. Pat. App. Pub. 2012/0052536,
filed Jul. 15, 2011, the complete disclosure of which is
incorporated herein by reference.
[0154] "Fermentation" includes the methods and products that are
disclosed in applications No. PCT/US2012/71093 published Jun. 27,
2013, PCT/US2012/71907 published Jun. 27, 2012, and
PCT/US2012/71083 published Jun. 27, 2012 the contents of which are
incorporated by reference herein in their entirety.
[0155] Mobile fermenters can be utilized, as described in
International App. No. PCT/US2007/074028 (which was filed Jul. 20,
2007, was published in English as WO 2008/011598 and designated the
United States) and has a U.S. issued U.S. Pat. No. 8,318,453, the
contents of which are incorporated herein in its entirety.
Similarly, the saccharification equipment can be mobile. Further,
saccharification and/or fermentation may be performed in part or
entirely during transit.
Fermentation Agents
[0156] The microorganism(s) used in fermentation can be
naturally-occurring microorganisms and/or engineered
microorganisms. For example, the microorganism can be a bacterium
(including, but not limited to, e.g., a cellulolytic bacterium), a
fungus, (including, but not limited to, e.g., a yeast), a plant, a
protist, e.g., a protozoa or a fungus-like protest (including, but
not limited to, e.g., a slime mold), or an alga. When the organisms
are compatible, mixtures of organisms can be utilized.
[0157] Suitable fermenting microorganisms have the ability to
convert carbohydrates, such as glucose, fructose, xylose,
arabinose, mannose, galactose, oligosaccharides or polysaccharides
into fermentation products. Fermenting microorganisms include
strains of the genus Saccharomyces spp. (including, but not limited
to, S. cerevisiae (baker's yeast), S. distaticus, S. uvarum), the
genus Kluyveromyces, (including, but not limited to, K. marxianus,
K. fragilis), the genus Candida (including, but not limited to, C.
pseudotropicalis, and C. brassicae), Pichia stipitis (a relative of
Candida shehatae), the genus Clavispora (including, but not limited
to, C. lusitaniae and C. opuntiae), the genus Pachysolen
(including, but not limited to, P. tannophilus), the genus
Bretannomyces (including, but not limited to, e.g., B. clausenii
(Philippidis, G. P., 1996, Cellulose bioconversion technology, in
Handbook on Bioethanol: Production and Utilization, Wyman, C. E.,
ed., Taylor & Francis, Washington, D.C., 179-212)). Other
suitable microorganisms include, for example, Zymomonas mobilis,
Clostridium spp. (including, but not limited to, C. thermocellum
(Philippidis, 1996, supra), C. saccharobutylacetonicum, C.
tyrobutyricum C. saccharobutylicum, C. Puniceum, C. beijernckii,
and C. acetobutylicum), Moniliella spp. (including but not limited
to M. pollinis, M. tomentosa, M. madida, M. nigrescens, M.
oedocephali, M. megachiliensis), Yarrowia lipolytica, Aureobasidium
sp., Trichosporonoides sp., Trigonopsis variabilis, Trichosporon
sp., Moniliellaacetoabutans sp., Typhula variabilis, Candida
magnoliae, Ustilaginomycetes sp., Pseudozyma tsukubaensis, yeast
species of genera Zygosaccharomyces, Debaryomyces, Hansenula and
Pichia, and fungi of the dematioid genus Torula (e.g., T.
corallina).
[0158] Additional microorganisms include, the Lactobacillus group.
Examples include, Lactobacillus casei, Lactobacillus rhamnosus,
Lactobacillus delbrueckii, Lactobacillus plantarum, Lactobacillus
coryniformis, e.g., Lactobacillus coryniformis subspecies torquens,
Lactobacillus pentosus, Lactobacillus brevis. Other microorganisms
include, Pediococus penosaceus, Rhizopus oryzae.
[0159] Several organisms, such as bacteria, yeasts and fungi, can
be utilized to ferment biomass derived products such as sugars and
alcohols to, for example succinic acid. For example, organisms can
be selected from; Actinobacillus succinogenes, Anaerobiospirillum
succiniciproducens, Mannheimia succiniciproducens, Ruminococcus
flayerfaciens, Ruminococcus albus, Fibrobacter succinogenes,
Bacteroides fragilis, Bacteroides ruminicola, Bacteroides
amylophilus, Bacteriodes succinogenes, Mannheimia
succiniciproducens, Corynebacterium glutamicum, Aspergillus niger,
Aspergillus fumigatus, Byssochlamys nivea, Lentinus degener,
Paecilomyces varioti, Penicillium viniferum, Saccharomyces
cerevisiae, Enterococcus faecali, Prevotella ruminicolas,
Debaryomyces hansenii, Candida catenulata VKM Y-5, C. mycoderma VKM
Y-240, C. rugosa VKM Y-67, C. paludigena VKM Y-2443, C. utilis VKM
Y-74, C. utilis 766, C. zeylanoides VKM Y-6, C. zeylanoides VKM
Y-14, C. zeylanoides VKM Y-2324, C. zeylanoides VKM Y-1543, C.
zeylanoides VKM Y-2595, C. valida VKM Y-934, Kluyveromyces
wickerhamii VKM Y-589, Pichia anomala VKM Y-118, P. besseyi VKM
Y-2084, P. media VKM Y-1381, P. guilliermondii H--P-4, P.
guilliermondii 916, P. inositovora VKM Y-2494, Saccharomyces
cerevisiae VKM Y-381, Torulopsis candida 127, T. candida 420,
Yarrowia lipolytica 12a, Y. lipolytica VKM Y-47, Y. lipolytica 69,
Y. lipolytica VKM Y-57, Y. lipolytica 212, Y. lipolytica 374/4, Y.
lipolytica 585, Y. lipolytica 695, Y. lipolytica 704, and mixtures
of these organisms.
[0160] Many such microbial strains are publicly available, either
commercially or through depositories such as the ATCC (American
Type Culture Collection, Manassas, Va., USA), the NRRL
(Agricultural Research Service Culture Collection, Peoria, Ill.,
USA), or the DSMZ (Deutsche Sammlung von Mikroorganismen and
Zellkulturen GmbH, Braunschweig, Germany), to name a few.
[0161] Commercially available yeasts include, for example, RED
STAR.RTM./Lesaffre Ethanol Red (available from Red Star/Lesaffre,
USA), FALI.RTM. (available from Fleischmann's Yeast, a division of
Burns Philip Food Inc., USA), SUPERSTART.RTM. (available from
Alltech, now Lalemand), GERT STRAND.RTM. (available from Gert
Strand AB, Sweden) and FERMOL.RTM. (available from DSM
Specialties).
Distillation
[0162] After fermentation, the resulting fluids can be distilled
using, for example, a "beer column" to separate ethanol and other
alcohols from the majority of water and residual solids. The vapor
exiting the beer column can be, e.g., 35% by weight ethanol and can
be fed to a rectification column. A mixture of nearly azeotropic
(92.5%) ethanol and water from the rectification column can be
purified to pure (99.5%) ethanol using vapor-phase molecular
sieves. The beer column bottoms can be sent to the first effect of
a three-effect evaporator. The rectification column reflux
condenser can provide heat for this first effect. After the first
effect, solids can be separated using a centrifuge and dried in a
rotary dryer. A portion (25%) of the centrifuge effluent can be
recycled to fermentation and the rest sent to the second and third
evaporator effects. Most of the evaporator condensate can be
returned to the process as fairly clean condensate with a small
portion split off to waste water treatment to prevent build-up of
low-boiling compounds.
Hydrocarbon-Containing Materials
[0163] In other embodiments utilizing the methods and systems
described herein, hydrocarbon-containing materials, for example
that are mixed with biomass can be processed. Any process described
herein can be used to treat any hydrocarbon-containing material
herein described. "Hydrocarbon-containing materials," as used
herein, is meant to include oil sands, oil shale, tar sands, coal
dust, coal slurry, bitumen, various types of coal, and other
naturally-occurring and synthetic materials that include both
hydrocarbon components and solid matter. The solid matter can
include wood, rock, sand, clay, stone, silt, drilling slurry, or
other solid organic and/or inorganic matter. The term can also
include waste products such as drilling waste and by-products,
refining waste and by-products, or other waste products containing
hydrocarbon components, such as asphalt shingling and covering,
asphalt pavement, etc.
Conveying Systems
[0164] Various conveying systems can be used to convey the biomass
material, for example, as previously discussed, to a vault, and
under an electron beam in a vault. Exemplary conveyors are belt
conveyors, pneumatic conveyors, screw conveyors, carts, trains,
trains or carts on rails, elevators, front loaders, backhoes,
cranes, various scrapers and shovels, trucks, and throwing devices
can be used. For example, vibratory conveyors can be used in
various processes described herein. Vibratory conveyors are
described in PCT/US2013/64289 filed Oct. 10, 2013 the full
disclosure of which is incorporated by reference herein.
[0165] Vibratory conveyors are particularly useful for spreading
the material and producing a uniform layer on the conveyor trough
surface. For example the initial feedstock can form a pile of
material that can be at least four feet high (e.g., at least about
3 feet, at least about 2 feet, at least about 1 foot, at least
about 6 inches, at least about 5 inches, at least about, 4 inches,
at least about 3 inches, at least about 2 inches, at least about 1
inch, at least about 1/2 inch) and spans less than the width of the
conveyor (e.g., less than about 10%, less than about 20%, less than
about 30%, less than about 40%, less than about 50%, less than
about 60%, less than about 70%, less than about 80%, less than
about 90%, less than about 95%, less than about 99%). The vibratory
conveyor can spread the material to span the entire width of the
conveyor trough and have a uniform thickness, preferably as
discussed above. In some cases, an additional spreading method can
be useful. For example, a spreader such as a broadcast spreader, a
drop spreader (e.g., a CHRISTY SPREADER.TM.) or combinations
thereof can be used to drop (e.g., place, pour, spill and/or
sprinkle) the feedstock over a wide area. Optionally, the spreader
can deliver the biomass as a wide shower or curtain onto the
vibratory conveyor. Additionally, a second conveyor, upstream from
the first conveyor (e.g., the first conveyor is used in the
irradiation of the feedstock), can drop biomass onto the first
conveyor, where the second conveyor can have a width transverse to
the direction of conveying smaller than the first conveyor. In
particular, when the second conveyor is a vibratory conveyor, the
feedstock is spread by the action of the second and first conveyor.
In some optional embodiments, the second conveyor ends in a bias
cross cut discharge (e.g., a bias cut with a ratio of 4:1) so that
the material can be dropped as a wide curtain (e.g., wider than the
width of the second conveyor) onto the first conveyor. The initial
drop area of the biomass by the spreader (e.g., broadcast spreader,
drop spreader, conveyor, or cross cut vibratory conveyor) can span
the entire width of the first vibratory conveyor, or it can span
part of this width. Once dropped onto the conveyor, the material is
spread even more uniformly by the vibrations of the conveyor so
that, preferably, the entire width of the conveyor is covered with
a uniform layer of biomass. In some embodiments combinations of
spreaders can be used. Some methods of spreading a feed stock are
described in U.S. Pat. No. 7,153,533, filed Jul. 23, 2002 and
published Dec. 26, 2006, the entire disclosure of which is
incorporated herein by reference.
[0166] Generally, it is preferred to convey the material as quickly
as possible through an electron beam to maximize throughput. For
example, the material can be conveyed at rates of at least 1
ft/min, e.g., at least 2 ft/min, at least 3 ft/min, at least 4
ft/min, at least 5 ft/min, at least 10 ft/min, at least 15 ft/min,
at least 20 ft/min, at least 25 ft/min, at least 30 ft/min, at
least 40 ft/min, at least 50 ft/min, at least 60 ft/min, at least
70 ft/min, at least 80 ft/min, at least 90 ft/min. The rate of
conveying is related to the beam current and targeted irradiation
dose, for example, for a 1/4 inch thick biomass spread over a 5.5
foot wide conveyor and 100 mA, the conveyor can move at about 20
ft/min to provide a useful irradiation dosage (e.g. about 10 Mrad
for a single pass), at 50 mA the conveyor can move at about 10
ft/min to provide approximately the same irradiation dosage.
[0167] The rate at which material can be conveyed depends on the
shape and mass of the material being conveyed, and the desired
treatment. Flowing materials e.g., particulate materials, are
particularly amenable to conveying with vibratory conveyors.
Conveying speeds can, for example be, at least 100 lb/hr (e.g., at
least 500 lb/hr, at least 1000 lb/hr, at least 2000 lb/hr, at least
3000 lb/hr, at least 4000 lb/hr, at least 5000 lb/hr, at least
10,000 lb/hr, at least 15,000 lb/hr, or even at least 25,000
lb/hr). Some typical conveying speeds can be between about 1000 and
10,000 lb/hr, (e.g., between about 1000 lb/hr and 8000 lb/hr,
between about 2000 and 7000 lb/hr, between about 2000 and 6000
lb/hr, between about 2000 and 5000 lb/hr, between about 2000 and
4500 lb/hr, between about 1500 and 5000 lb/hr, between about 3000
and 7000 lb/hr, between about 3000 and 6000 lb/hr, between about
4000 and 6000 lb/hr and between about 4000 and 5000 lb/hr). Typical
conveying speeds depend on the density of the material. For
example, for a biomass with a density of about 35 lb/ft3, and a
conveying speed of about 5000 lb/hr, the material is conveyed at a
rate of about 143 ft3/hr, if the material is 1/4'' thick and is in
a trough 5.5 ft wide, the material is conveyed at a rate of about
1250 ft/hr (about 21 ft/min). Rates of conveying the material can
therefore vary greatly. Preferably, for example, a 1/4'' thick
layer of biomass, is conveyed at speeds of between about 5 and 100
ft/min (e.g. between about 5 and 100 ft/min, between about 6 and
100 ft/min, between about 7 and 100 ft/min, between about 8 and 100
ft/min, between about 9 and 100 ft/min, between about 10 and 100
ft/min, between about 11 and 100 ft/min, between about 12 and 100
ft/min, between about 13 and 100 ft/min, between about 14 and 100
ft/min, between about 15 and 100 ft/min, between about 20 and 100
ft/min, between about 30 and 100 ft/min, between about 40 and 100
ft/min, between about 2 and 60 ft/min, between about 3 and 60
ft/min, between about 5 and 60 ft/min, between about 6 and 60
ft/min, between about 7 and 60 ft/min, between about 8 and 60
ft/min, between about 9 and 60 ft/min, between about 10 and 60
ft/min, between about 15 and 60 ft/min, between about 20 and 60
ft/min, between about 30 and 60 ft/min, between about 40 and 60
ft/min, between about 2 and 50 ft/min, between about 3 and 50
ft/min, between about 5 and 50 ft/min, between about 6 and 50
ft/min, between about 7 and 50 ft/min, between about 8 and 50
ft/min, between about 9 and 50 ft/min, between about 10 and 50
ft/min, between about 15 and 50 ft/min, between about 20 and 50
ft/min, between about 30 and 50 ft/min, between about 40 and 50
ft/min). It is preferable that the material be conveyed at a
constant rate, for example, to help maintain a constant irradiation
of the material as it passes under the electron beam (e.g., shower,
field).
[0168] The vibratory conveyors described can include screens used
for sieving and sorting materials. Port openings on the side or
bottom of the troughs can be used for sorting, selecting or
removing specific materials, for example, by size or shape. Some
conveyors have counterbalances to reduce the dynamic forces on the
support structure. Some vibratory conveyors are configured as
spiral elevators, are designed to curve around surfaces and/or are
designed to drop material from one conveyor to another (e.g., in a
step, cascade or as a series of steps or a stair). Along with
conveying materials conveyors can be used, by themselves or coupled
with other equipment or systems, for screening, separating,
sorting, classifying, distributing, sizing, inspection, picking,
metal removing, freezing, blending, mixing, orienting, heating,
cooking, drying, dewatering, cleaning, washing, leaching,
quenching, coating, de-dusting and/or feeding. The conveyors can
also include covers (e.g., dust-tight covers), side discharge
gates, bottom discharge gates, special liners (e.g., anti-stick,
stainless steel, rubber, custom steal, and or grooved), divided
troughs, quench pools, screens, perforated plates, detectors (e.g.,
metal detectors), high temperature designs, food grade designs,
heaters, dryers and or coolers. In addition, the trough can be of
various shapes, for example, flat bottomed, vee shaped bottom,
flanged at the top, curved bottom, flat with ridges in any
direction, tubular, half pipe, covered or any combinations of
these. In particular, the conveyors can be coupled with an
irradiation systems and/or equipment.
[0169] The conveyors (e.g., vibratory conveyor) can be made of
corrosion resistant materials. The conveyors can utilize structural
materials that include stainless steel (e.g., 304, 316 stainless
steel, HASTELLOY.RTM. ALLOYS and INCONEL.RTM. Alloys). For example,
HASTELLOY.RTM. Corrosion-Resistant alloys from Hynes (Kokomo, Ind.,
USA) such as HASTELLOY.RTM. B-3.RTM. ALLOY, HASTELLOY.RTM.
HYBRID-BC1.RTM. ALLOY, HASTELLOY.RTM. C-4 ALLOY, HASTELLOY.RTM.
C-22.RTM. ALLOY, HASTELLOY.RTM. C-22HS.RTM. ALLOY, HASTELLOY.RTM.
C-276 ALLOY, HASTELLOY.RTM. C-2000.RTM. ALLOY, HASTELLOY.RTM.
G-30.RTM. ALLOY, HASTELLOY.RTM. G-35.RTM. ALLOY, HASTELLOY.RTM. N
ALLOY and HASTELLOY.RTM. ULTIMET.RTM. alloy.
[0170] The vibratory conveyors can include non-stick release
coatings, for example, TUFFLON.TM. (Dupont, Del., USA). The
vibratory conveyors can also include corrosion resistant coatings.
For example, coatings that can be supplied from Metal Coatings Corp
(Houston, Tex., USA) and others such as Fluoropolymer, XYLAN.RTM.,
Molybdenum Disulfide, Epoxy Phenolic, Phosphate-ferrous metal
coating, Polyurethane-high gloss topcoat for epoxy, inorganic zinc,
Poly Tetrafluoro ethylene, PPS/RYTON.RTM., fluorinated ethylene
propylene, PVDF/DYKOR.RTM., ECTFE/HALAR.RTM. and Ceramic Epoxy
Coating. The coatings can improve resistance to process gases
(e.g., ozone), chemical corrosion, pitting corrosion, galling
corrosion and oxidation.
[0171] Optionally, in addition to the conveying systems described
herein, one or more other conveying systems can be enclosed. When
using an enclosure, the enclosed conveyor can also be purged with
an inert gas so as to maintain an atmosphere at a reduced oxygen
level. Keeping oxygen levels low avoids the formation of ozone
which in some instances is undesirable due to its reactive and
toxic nature. For example, the oxygen can be less than about 20%
(e.g., less than about 10%, less than about 1%, less than about
0.1%, less than about 0.01%, or even less than about 0.001%
oxygen). Purging can be done with an inert gas including, but not
limited to, nitrogen, argon, helium or carbon dioxide. This can be
supplied, for example, from a boil off of a liquid source (e.g.,
liquid nitrogen or helium), generated or separated from air in
situ, or supplied from tanks. The inert gas can be recirculated and
any residual oxygen can be removed using a catalyst, such as a
copper catalyst bed. Alternatively, combinations of purging,
recirculating and oxygen removal can be done to keep the oxygen
levels low.
[0172] The enclosed conveyor can also be purged with a reactive gas
that can react with the biomass. This can be done before, during or
after the irradiation process. The reactive gas can be, but is not
limited to, nitrous oxide, ammonia, oxygen, ozone, hydrocarbons,
aromatic compounds, amides, peroxides, azides, halides, oxyhalides,
phosphides, phosphines, arsines, sulfides, thiols, boranes and/or
hydrides. The reactive gas can be activated in the enclosure, e.g.,
by irradiation (e.g., electron beam, UV irradiation, microwave
irradiation, heating, IR radiation), so that it reacts with the
biomass. The biomass itself can be activated, for example by
irradiation. Preferably the biomass is activated by the electron
beam, to produce radicals which then react with the activated or
unactivated reactive gas, e.g., by radical coupling or
quenching.
[0173] Purging gases supplied to an enclosed conveyor can also be
cooled, for example below about 25.degree. C., below about
0.degree. C., below about -40.degree. C., below about -80.degree.
C., below about -120.degree. C. For example, the gas can be boiled
off from a compressed gas such as liquid nitrogen or sublimed from
solid carbon dioxide. As an alternative example, the gas can be
cooled by a chiller or part of or the entire conveyor can be
cooled.
Other Embodiments
[0174] Any material, processes or processed materials discussed
herein can be used to make products and/or intermediates such as
composites, fillers, binders, plastic additives, adsorbents and
controlled release agents. The methods can include densification,
for example, by applying pressure and heat to the materials. For
example, composites can be made by combining fibrous materials with
a resin or polymer. For example, radiation cross-linkable resin,
e.g., a thermoplastic resin can be combined with a fibrous material
to provide a fibrous material/cross-linkable resin combination.
Such materials can be, for example, useful as building materials,
protective sheets, containers and other structural materials (e.g.,
molded and/or extruded products). Absorbents can be, for example,
in the form of pellets, chips, fibers and/or sheets. Adsorbents can
be used, for example, as pet bedding, packaging material or in
pollution control systems. Controlled release matrices can also be
the form of, for example, pellets, chips, fibers and or sheets. The
controlled release matrices can, for example, be used to release
drugs, biocides, fragrances. For example, composites, absorbents
and control release agents and their uses are described in U.S.
Serial No. PCT/US2006/010648, filed Mar. 23, 2006, and U.S. Pat.
No. 8,074,910 filed Nov. 22, 2011, the entire disclosures of which
are herein incorporated by reference.
[0175] In some instances the biomass material is treated at a first
level to reduce recalcitrance, e.g., utilizing accelerated
electrons, to selectively release one or more sugars (e.g.,
xylose). The biomass can then be treated to a second level to
release one or more other sugars (e.g., glucose). Optionally the
biomass can be dried between treatments. The treatments can include
applying chemical and biochemical treatments to release the sugars.
For example, a biomass material can be treated to a level of less
than about 20 Mrad (e.g., less than about 15 Mrad, less than about
10 Mrad, less than about 5 Mrad, less than about 2 Mrad) and then
treated with a solution of sulfuric acid, containing less than 10%
sulfuric acid (e.g., less than about 9%, less than about 8%, less
than about 7%, less than about 6%, less than about 5%, less than
about 4%, less than about 3%, less than about 2%, less than about
1%, less than about 0.75%, less than about 0.50%, less than about
0.25%) to release xylose. Xylose, for example that is released into
solution, can be separated from solids and optionally the solids
washed with a solvent/solution (e.g., with water and/or acidified
water). Optionally, the Solids can be dried, for example in air
and/or under vacuum optionally with heating (e.g., below about 150
deg C., below about 120 deg C.) to a water content below about 25
wt % (below about 20 wt. %, below about 15 wt. %, below about 10
wt. %, below about 5 wt. %). The solids can then be treated with a
level of less than about 30 Mrad (e.g., less than about 25 Mrad,
less than about 20 Mrad, less than about 15 Mrad, less than about
10 Mrad, less than about 5 Mrad, less than about 1 Mrad or even not
at all) and then treated with an enzyme (e.g., a cellulase) to
release glucose. The glucose (e.g., glucose in solution) can be
separated from the remaining solids. The solids can then be further
processed, for example utilized to make energy or other products
(e.g., lignin derived products).
Flavors, Fragrances and Colorants
[0176] Any of the products and/or intermediates described herein,
for example, produced by the processes, systems and/or equipment
described herein, can be combined with flavors, fragrances,
colorants and/or mixtures of these. For example, any one or more of
(optionally along with flavors, fragrances and/or colorants)
sugars, organic acids, fuels, polyols, such as sugar alcohols,
biomass, fibers and composites can be combined with (e.g.,
formulated, mixed or reacted) or used to make other products. For
example, one or more such product can be used to make soaps,
detergents, candies, drinks (e.g., cola, wine, beer, liquors such
as gin or vodka, sports drinks, coffees, teas), syrups,
pharmaceuticals, adhesives, sheets (e.g., woven, none woven,
filters, tissues) and/or composites (e.g., boards). For example,
one or more such product can be combined with herbs, flowers,
petals, spices, vitamins, potpourri, or candles. For example, the
formulated, mixed or reacted combinations can have
flavors/fragrances of grapefruit, orange, apple, raspberry, banana,
lettuce, celery, cinnamon, chocolate, vanilla, peppermint, mint,
onion, garlic, pepper, saffron, ginger, milk, wine, beer, tea, lean
beef, fish, clams, olive oil, coconut fat, pork fat, butter fat,
beef bouillon, legume, potatoes, marmalade, ham, coffee and
cheeses.
[0177] Flavors, fragrances and colorants can be added in any
amount, such as between about 0.001 wt. % to about 30 wt. %, e.g.,
between about 0.01 to about 20, between about 0.05 to about 10, or
between about 0.1 wt. % to about 5 wt. %. These can be formulated,
mixed and or reacted (e.g., with any one of more product or
intermediate described herein) by any means and in any order or
sequence (e.g., agitated, mixed, emulsified, gelled, infused,
heated, sonicated, and/or suspended). Fillers, binders, emulsifier,
antioxidants can also be utilized, for example protein gels,
starches and silica.
[0178] In one embodiment the flavors, fragrances and colorants can
be added to the biomass immediately after the biomass is irradiated
such that the reactive sites created by the irradiation may react
with reactive compatible sites of the flavors, fragrances, and
colorants.
[0179] The flavors, fragrances and colorants can be natural and/or
synthetic materials. These materials can be one or more of a
compound, a composition or mixtures of these (e.g., a formulated or
natural composition of several compounds). Optionally, the flavors,
fragrances, antioxidants and colorants can be derived biologically,
for example, from a fermentation process (e.g., fermentation of
saccharified materials as described herein). Alternatively, or
additionally these flavors, fragrances and colorants can be
harvested from a whole organism (e.g., plant, fungus, animal,
bacteria or yeast) or a part of an organism. The organism can be
collected and or extracted to provide color, flavors, fragrances
and/or antioxidant by any means including utilizing the methods,
systems and equipment described herein, hot water extraction,
supercritical fluid extraction, chemical extraction (e.g., solvent
or reactive extraction including acids and bases), mechanical
extraction (e.g., pressing, comminuting, filtering), utilizing an
enzyme, utilizing a bacteria such as to break down a starting
material, and combinations of these methods. The compounds can be
derived by a chemical reaction, for example, the combination of a
sugar (e.g., as produced as described herein) with an amino acid
(Maillard reaction). The flavor, fragrance, antioxidant and/or
colorant can be an intermediate and or product produced by the
methods, equipment or systems described herein, for example and
ester and a lignin derived product.
[0180] Some examples of flavor, fragrances or colorants are
polyphenols. Polyphenols are pigments responsible for the red,
purple and blue colorants of many fruits, vegetables, cereal
grains, and flowers. Polyphenols also can have antioxidant
properties and often have a bitter taste. The antioxidant
properties make these important preservatives. On class of
polyphenols are the flavonoids, such as Anthocyanidines,
flavanonols, flavan-3-ols, s, flavanones and flavanonols. Other
phenolic compounds that can be used include phenolic acids and
their esters, such as chlorogenic acid and polymeric tannins.
[0181] Among the colorants inorganic compounds, minerals or organic
compounds can be used, for example titanium dioxide, zinc oxide,
aluminum oxide, cadmium yellow (E.g., CdS), cadmium orange (e.g.,
CdS with some Se), alizarin crimson (e.g., synthetic or
non-synthetic rose madder), ultramarine (e.g., synthetic
ultramarine, natural ultramarine, synthetic ultramarine violet),
cobalt blue, cobalt yellow, cobalt green, viridian (e.g., hydrated
chromium(III)oxide), chalcophylite, conichalcite, cornubite,
cornwallite and liroconite. Black pigments such as carbon black and
self-dispersed blacks may be used.
[0182] Some flavors and fragrances that can be utilized include
ACALEA TBHQ, ACET C-6, ALLYL AMYL GLYCOLATE, ALPHA TERPINEOL,
AMBRETTOLIDE, AMBRINOL 95, ANDRANE, APHERMATE, APPLELIDE,
BACDANOL.RTM., BERGAMAL, BETA IONONE EPDXIDE, BETA NAPHTHYL
ISO-BUTYL ETHER, BICYCLONONALACTONE, BORNAFIX.RTM., CANTHOXAL,
CASHMERAN.RTM., CASHMERAN.RTM. VELVET, CASSIFFIX.RTM., CEDRAFIX,
CEDRAMBER.RTM., CEDRYL ACETATE, CELESTOLIDE, CINNAMALVA, CITRAL
DIMETHYL ACETATE, CITROLATE.TM., CITRONELLOL 700, CITRONELLOL 950,
CITRONELLOL COEUR, CITRONELLYL ACETATE, CITRONELLYL ACETATE PURE,
CITRONELLYL FORMATE, CLARYCET, CLONAL, CONIFERAN, CONIFERAN PURE,
CORTEX ALDEHYDE 50% PEOMOSA, CYCLABUTE, CYCLACET.RTM.,
CYCLAPROP.RTM., CYCLEMAX.TM., CYCLOHEXYL ETHYL ACETATE, DAMASCOL,
DELTA DAMASCONE, DIHYDRO CYCLACET, DIHYDRO MYRCENOL, DIHYDRO
TERPINEOL, DIHYDRO TERPINYL ACETATE, DIMETHYL CYCLORMOL, DIMETHYL
OCTANOL PQ, DIMYRCETOL, DIOLA, DIPENTENE, DULCINYL.RTM.
RECRYSTALLIZED, ETHYL-3-PHENYL GLYCIDATE, FLEURAMONE, FLEURANIL,
FLORAL SUPER, FLORALOZONE, FLORIFFOL, FRAISTONE, FRUCTONE,
GALAXOLIDE.RTM. 50, GALAXOLIDE.RTM. 50 BB, GALAXOLIDE.RTM. 50 IPM,
GALAXOLIDE.RTM. UNDILUTED, GALBASCONE, GERALDEHYDE, GERANIOL 5020,
GERANIOL 600 TYPE, GERANIOL 950, GERANIOL 980 (PURE), GERANIOL CFT
COEUR, GERANIOL COEUR, GERANYL ACETATE COEUR, GERANYL ACETATE,
PURE, GERANYL FORMATE, GRISALVA, GUAIYL ACETATE, HELIONAL.TM.,
HERBAC, HERBALIMET.TM., HEXADECANOLIDE, HEXALON, HEXENYL SALICYLATE
CIS 3-, HYACINTH BODY, HYACINTH BODY NO. 3, HYDRATROPIC
ALDEHYDE.DMA, HYDROXYOL, INDOLAROME, INTRELEVEN ALDEHYDE,
INTRELEVEN ALDEHYDE SPECIAL, IONONE ALPHA, IONONE BETA, ISO CYCLO
CITRAL, ISO CYCLO GERANIOL, ISO E SUPER.RTM., ISOBUTYL QUINOLINE,
JASMAL, JESSEMAL.RTM., KHARISMAL.RTM., KHARISMAL.RTM. SUPER,
KHUSINIL, KOAVONE.RTM., KOHINOOL.RTM., LIFFAROMET.TM., LIMOXAL,
LINDENOL.TM., LYRAL.RTM., LYRAME SUPER, MANDARIN ALD 10% TRI ETH,
CITR, MARITIMA, MCK CHINESE, MEIJIFF.TM., MELAFLEUR, MELOZONE,
METHYL ANTHRANILATE, METHYL IONONE ALPHA EXTRA, METHYL IONONE GAMMA
A, METHYL IONONE GAMMA COEUR, METHYL IONONE GAMMA PURE, METHYL
LAVENDER KETONE, MONTAVERDI.RTM., MUGUESIA, MUGUET ALDEHYDE 50,
MUSK Z4, MYRAC ALDEHYDE, MYRCENYL ACETATE, NECTARATET.TM., NEROL
900, NERYL ACETATE, OCIMENE, OCTACETAL, ORANGE FLOWER ETHER,
ORIVONE, ORRINIFF 25%, OXASPIRANE, OZOFLEUR, PAMPLEFLEUR.RTM.,
PEOMOSA, PHENOXANOL.RTM., PICONIA, PRECYCLEMONE B, PRENYL ACETATE,
PRISMANTOL, RESEDA BODY, ROSALVA, ROSAMUSK, SANJINOL,
SANTALIFFT.TM., SYVERTAL, TERPINEOL, TERPINOLENE 20, TERPINOLENE 90
PQ, TERPINOLENE RECT., TERPINYL ACETATE, TERPINYL ACETATE JAX,
TETRAHYDRO, MUGUOL.RTM., TETRAHYDRO MYRCENOL, TETRAMERAN,
TIMBERSILK.TM., TOBACAROL, TRIMOFIX.RTM. O TT, TRIPLAL.RTM.,
TRISAMBER.RTM., VANORIS, VERDOX.TM., VERDOX.TM. HC, VERTENEX.RTM.,
VERTENEX.RTM. HC, VERTOFIX.RTM. COEUR, VERTOLIFF, VERTOLIFF ISO,
VIOLIFF, VIVALDIE, ZENOLIDE, ABS INDIA 75 PCT MIGLYOL, ABS MOROCCO
50 PCT DPG, ABS MOROCCO 50 PCT TEC, ABSOLUTE FRENCH, ABSOLUTE
INDIA, ABSOLUTE MD 50 PCT BB, ABSOLUTE MOROCCO, CONCENTRATE PG,
TINCTURE 20 PCT, AMBERGRIS, AMBRETTE ABSOLUTE, AMBRETTE SEED OIL,
ARMOISE OIL 70 PCT THUYONE, BASIL ABSOLUTE GRAND VERT, BASIL GRAND
VERT ABS MD, BASIL OIL GRAND VERT, BASIL OIL VERVEINA, BASIL OIL
VIETNAM, BAY OIL TERPENELESS, BEESWAX ABS N G, BEESWAX ABSOLUTE,
BENZOIN RESINOID SIAM, BENZOIN RESINOID SIAM 50 PCT DPG, BENZOIN
RESINOID SIAM 50 PCT PG, BENZOIN RESINOID SIAM 70.5 PCT TEC,
BLACKCURRANT BUD ABS 65 PCT PG, BLACKCURRANT BUD ABS MD 37 PCT TEC,
BLACKCURRANT BUD ABS MIGLYOL, BLACKCURRANT BUD ABSOLUTE BURGUNDY,
BOIS DE ROSE OIL, BRAN ABSOLUTE, BRAN RESINOID, BROOM ABSOLUTE
ITALY, CARDAMOM GUATEMALA CO.sub.2 EXTRACT, CARDAMOM OIL GUATEMALA,
CARDAMOM OIL INDIA, CARROT HEART, CASSIE ABSOLUTE EGYPT, CASSIE
ABSOLUTE MD 50 PCT IPM, CASTOREUM ABS 90 PCT TEC, CASTOREUM ABS C
50 PCT MIGLYOL, CASTOREUM ABSOLUTE, CASTOREUM RESINOID, CASTOREUM
RESINOID 50 PCT DPG, CEDROL CEDRENE, CEDRUS ATLANTICA OIL REDIST,
CHAMOMILE OIL ROMAN, CHAMOMILE OIL WILD, CHAMOMILE OIL WILD LOW
LIMONENE, CINNAMON BARK OIL CEYLAN, CISTE ABSOLUTE, CISTE ABSOLUTE
COLORLESS, CITRONELLA OIL ASIA IRON FREE, CIVET ABS 75 PCT PG,
CIVET ABSOLUTE, CIVET TINCTURE 10 PCT, CLARY SAGE ABS FRENCH DECOL,
CLARY SAGE ABSOLUTE FRENCH, CLARY SAGE C'LESS 50 PCT PG, CLARY SAGE
OIL FRENCH, COPAIBA BALSAM, COPAIBA BALSAM OIL, CORIANDER SEED OIL,
CYPRESS OIL, CYPRESS OIL ORGANIC, DAVANA OIL, GALBANOL, GALBANUM
ABSOLUTE COLORLESS, GALBANUM OIL, GALBANUM RESINOID, GALBANUM
RESINOID 50 PCT DPG, GALBANUM RESINOID HERCOLYN BHT, GALBANUM
RESINOID TEC BHT, GENTIANE ABSOLUTE MD 20 PCT BB, GENTIANE
CONCRETE, GERANIUM ABS EGYPT MD, GERANIUM ABSOLUTE EGYPT, GERANIUM
OIL CHINA, GERANIUM OIL EGYPT, GINGER OIL 624, GINGER OIL RECTIFIED
SOLUBLE, GUAIACWOOD HEART, HAY ABS MD 50 PCT BB, HAY ABSOLUTE, HAY
ABSOLUTE MD 50 PCT TEC, HEALINGWOOD, HYSSOP OIL ORGANIC, IMMORTELLE
ABS YUGO MD 50 PCT TEC, IMMORTELLE ABSOLUTE SPAIN, IMMORTELLE
ABSOLUTE YUGO, JASMIN ABS INDIA MD, JASMIN ABSOLUTE EGYPT, JASMIN
ABSOLUTE INDIA, ASMIN ABSOLUTE MOROCCO, JASMIN ABSOLUTE SAMBAC,
JONQUILLE ABS MD 20 PCT BB, JONQUILLE ABSOLUTE France, JUNIPER
BERRY OIL FLG, JUNIPER BERRY OIL RECTIFIED SOLUBLE, LABDANUM
RESINOID 50 PCT TEC, LABDANUM RESINOID BB, LABDANUM RESINOID MD,
LABDANUM RESINOID MD 50 PCT BB, LAVANDIN ABSOLUTE H, LAVANDIN
ABSOLUTE MD, LAVANDIN OIL ABRIAL ORGANIC, LAVANDIN OIL GROSSO
ORGANIC, LAVANDIN OIL SUPER, LAVENDER ABSOLUTE H, LAVENDER ABSOLUTE
MD, LAVENDER OIL COUMARIN FREE, LAVENDER OIL COUMARIN FREE ORGANIC,
LAVENDER OIL MAILLETTE ORGANIC, LAVENDER OIL MT, MACE ABSOLUTE BB,
MAGNOLIA FLOWER OIL LOW METHYL EUGENOL, MAGNOLIA FLOWER OIL,
MAGNOLIA FLOWER OIL MD, MAGNOLIA LEAF OIL, MANDARIN OIL MD,
MANDARIN OIL MD BHT, MATE ABSOLUTE BB, MOSS TREE ABSOLUTE MD TEX
IFRA 43, MOSS-OAK ABS MD TEC IFRA 43, MOSS-OAK ABSOLUTE IFRA 43,
MOSS-TREE ABSOLUTE MD IPM IFRA 43, MYRRH RESINOID BB, MYRRH
RESINOID MD, MYRRH RESINOID TEC, MYRTLE OIL IRON FREE, MYRTLE OIL
TUNISIA RECTIFIED, NARCISSE ABS MD 20 PCT BB, NARCISSE ABSOLUTE
FRENCH, NEROLI OIL TUNISIA, NUTMEG OIL TERPENELESS, OEILLET
ABSOLUTE, OLIBANUM RESINOID, OLIBANUM RESINOID BB, OLIBANUM
RESINOID DPG, OLIBANUM RESINOID EXTRA 50 PCT DPG, OLIBANUM RESINOID
MD, OLIBANUM RESINOID MD 50 PCT DPG, OLIBANUM RESINOID TEC,
OPOPONAX RESINOID TEC, ORANGE BIGARADE OIL MD BHT, ORANGE BIGARADE
OIL MD SCFC, ORANGE FLOWER ABSOLUTE TUNISIA, ORANGE FLOWER WATER
ABSOLUTE TUNISIA, ORANGE LEAF ABSOLUTE, ORANGE LEAF WATER ABSOLUTE
TUNISIA, ORRIS ABSOLUTE ITALY, ORRIS CONCRETE 15 PCT IRONE, ORRIS
CONCRETE 8 PCT IRONE, ORRIS NATURAL 15 PCT IRONE 4095C, ORRIS
NATURAL 8 PCT IRONE 2942C, ORRIS RESINOID, OSMANTHUS ABSOLUTE,
OSMANTHUS ABSOLUTE MD 50 PCT BB, PATCHOULI HEART N.degree. 3,
PATCHOULI OIL INDONESIA, PATCHOULI OIL INDONESIA IRON FREE,
PATCHOULI OIL INDONESIA MD, PATCHOULI OIL REDIST, PENNYROYAL HEART,
PEPPERMINT ABSOLUTE MD, PETITGRAIN BIGARADE OIL TUNISIA, PETITGRAIN
CITRONNIER OIL, PETITGRAIN OIL PARAGUAY TERPENELESS, PETITGRAIN OIL
TERPENELESS STAB, PIMENTO BERRY OIL, PIMENTO LEAF OIL, RHODINOL EX
GERANIUM CHINA, ROSE ABS BULGARIAN LOW METHYL EUGENOL, ROSE ABS
MOROCCO LOW METHYL EUGENOL, ROSE ABS TURKISH LOW METHYL EUGENOL,
ROSE ABSOLUTE, ROSE ABSOLUTE BULGARIAN, ROSE ABSOLUTE DAMASCENA,
ROSE ABSOLUTE MD, ROSE ABSOLUTE MOROCCO, ROSE ABSOLUTE TURKISH,
ROSE OIL BULGARIAN, ROSE OIL DAMASCENA LOW METHYL EUGENOL, ROSE OIL
TURKISH, ROSEMARY OIL CAMPHOR ORGANIC, ROSEMARY OIL TUNISIA,
SANDALWOOD OIL INDIA, SANDALWOOD OIL INDIA RECTIFIED, SANTALOL,
SCHINUS MOLLE OIL, ST JOHN BREAD TINCTURE 10 PCT, STYRAX RESINOID,
STYRAX RESINOID, TAGETE OIL, TEA TREE HEART, TONKA BEAN ABS 50 PCT
SOLVENTS, TONKA BEAN ABSOLUTE, TUBEROSE ABSOLUTE INDIA, VETIVER
HEART EXTRA, VETIVER OIL HAITI, VETIVER OIL HAITI MD, VETIVER OIL
JAVA, VETIVER OIL JAVA MD, VIOLET LEAF ABSOLUTE EGYPT, VIOLET LEAF
ABSOLUTE EGYPT DECOL, VIOLET LEAF ABSOLUTE FRENCH, VIOLET LEAF
ABSOLUTE MD 50 PCT BB, WORMWOOD OIL TERPENELESS, YLANG EXTRA OIL,
YLANG III OIL and combinations of these.
[0183] The colorants can be among those listed in the Color Index
International by the Society of Dyers and Colourists. Colorants
include dyes and pigments and include those commonly used for
coloring textiles, paints, inks and inkjet inks. Some colorants
that can be utilized include carotenoids, arylide yellows,
diarylide yellows, B-naphthols, naphthols, benzimidazolones, disazo
condensation pigments, pyrazolones, nickel azo yellow,
phthalocyanines, quinacridones, perylenes and perinones,
isoindolinone and isoindoline pigments, triarylcarbonium pigments,
diketopyrrolo-pyrrole pigments, thioindigoids. Cartenoids include,
for example, alpha-carotene, beta-carotene, gamma-carotene,
lycopene, lutein and astaxanthin, Annatto extract, Dehydrated beets
(beet powder), Canthaxanthin, Caramel, .beta.-Apo-8'-carotenal,
Cochineal extract, Carmine, Sodium copper chlorophyllin, Toasted
partially defatted cooked cottonseed flour, Ferrous gluconate,
Ferrous lactate, Grape color extract, Grape skin extract
(enocianina), Carrot oil, Paprika, Paprika oleoresin, Mica-based
pearlescent pigments, Riboflavin, Saffron, Titanium dioxide, Tomato
lycopene extract; tomato lycopene concentrate, Turmeric, Turmeric
oleoresin, FD&C Blue No. 1, FD&C Blue No. 2, FD&C Green
No. 3, Orange B, Citrus Red No. 2, FD&C Red No. 3, FD&C Red
No. 40, FD&C Yellow No. 5, FD&C Yellow No. 6, Alumina
(dried aluminum hydroxide), Calcium carbonate, Potassium sodium
copper chlorophyllin (chlorophyllin-copper complex),
Dihydroxyacetone, Bismuth oxychloride, Ferric ammonium
ferrocyanide, Ferric ferrocyanide, Chromium hydroxide green,
Chromium oxide greens, Guanine, Pyrophyllite, Talc, Aluminum
powder, Bronze powder, Copper powder, Zinc oxide, D&C Blue No.
4, D&C Green No. 5, D&C Green No. 6, D&C Green No. 8,
D&C Orange No. 4, D&C Orange No. 5, D&C Orange No. 10,
D&C Orange No. 11, FD&C Red No. 4, D&C Red No. 6,
D&C Red No. 7, D&C Red No. 17, D&C Red No. 21, D&C
Red No. 22, D&C Red No. 27, D&C Red No. 28, D&C Red No.
30, D&C Red No. 31, D&C Red No. 33, D&C Red No. 34,
D&C Red No. 36, D&C Red No. 39, D&C Violet No. 2,
D&C Yellow No. 7, Ext. D&C Yellow No. 7, D&C Yellow No.
8, D&C Yellow No. 10, D&C Yellow No. 11, D&C Black No.
2, D&C Black No. 3 (3), D&C Brown No. 1, Ext. D&C,
Chromium-cobalt-aluminum oxide, Ferric ammonium citrate,
Pyrogallol, Logwood extract,
1,4-Bis[(2-hydroxy-ethyl)amino]-9,10-anthracenedione
bis(2-propenoic)ester copolymers, 1,4-Bis
[(2-methylphenyl)amino]-9,10-anthracenedione,
1,4-Bis[4-(2-methacryloxyethyl) phenylamino]anthraquinone
copolymers, Carbazole violet, Chlorophyllin-copper complex,
Chromium-cobalt-aluminum oxide, C.I. Vat Orange 1,
2-[[2,5-Diethoxy-4-[(4-methylphenyl)thiol]phenyl]azo]-1,3,5-benzenetriol,
16,23-Dihydrodinaphtho[2,3-a:2',3'-i]naphth[2',':6,7]
indolo[2,3-c]carbazole-5,10,15,17,22,24-hexone,
N,N'-(9,10-Dihydro-9,10-dioxo-1,5-anthracenediyl)bisbenzamide,
7,16-Dichloro-6,15-dihydro-5,9,14,18-anthrazinetetrone,
16,17-Dimethoxydinaphtho (1,2,3-cd:3',2',1'-lm)
perylene-5,10-dione, Poly(hydroxyethyl methacrylate)-dye
copolymers(3), Reactive Black 5, Reactive Blue 21, Reactive Orange
78, Reactive Yellow 15, Reactive Blue No. 19, Reactive Blue No. 4,
C.I. Reactive Red 11, C.I. Reactive Yellow 86, C.I. Reactive Blue
163, C.I. Reactive Red 180,
4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-on-
e (solvent Yellow 18),
6-Ethoxy-2-(6-ethoxy-3-oxobenzo[b]thien-2(3H)--
ylidene)benzo[b]thiophen-3(2H)-one, Phthalocyanine green, Vinyl
alcohol/methyl methacrylate-dye reaction products, C.I. Reactive
Red 180, C.I. Reactive Black 5, C.I. Reactive Orange 78, C.I.
Reactive Yellow 15, C.I. Reactive Blue 21, Disodium
1-amino-4-[[4-[(2-bromo-1-oxoallyl)amino]-2-sulphonatophenyl]amino]-9,10--
dihydro-9,10-dioxoanthracene-2-sulphonate (Reactive Blue 69),
D&C Blue No. 9, [Phthalocyaninato(2-)]copper and mixtures of
these.
EXAMPLES
Saccharification
[0184] A cylindrical tank with a diameter of 32 Inches, 64 Inches
in height and fit with ASME dished heads (top and bottom) was used
in the saccharification. The tank was also equipped with a
hydrofoil-mixing blade 16'' wide. Heating was provided by flowing
hot water through a half pipe jacket surrounding the tank.
[0185] The tank was charged with 200 kg water, 80 kg of biomass,
and 18 kg of DUE.TM. Cellulase enzyme. Biomass was corncob that had
been hammer milled and screened to a size of between 40 and 10
mesh. The biomass was irradiated with an electron beam to a total
dosage of 35 Mrad. The pH of the mixture was adjusted and
maintained automatically throughout the saccharification at 4.8
using Ca(OH).sub.2. This combination was heated to 53 deg. C.,
stirred at 180 rpm (1.8 Amp at 460V) for about 24 hours after which
the saccharification was considered completed.
[0186] A portion of this material was screened through a 20-mesh
screen and the solution stored in an 8 gal carboy at 4 deg. C.
Biomass Produced Ethanol and Xylose Stream
[0187] About 400 mL of the saccharified material was decanted into
a 1 L New Brunswick BioFlow 115 Bioreactor. The material was
aerated and heated to 30 deg. C. prior to inoculation. Stirring was
set at 50 rpm. The pH was measured at 5.2, which is acceptable for
fermentation so it was not adjusted. Aeration was discontinued and
the contents of the bioreactor were inoculated with 5 mg of
THERMOSACC.RTM. Dry Yeast (Lallemand, Inc.). Fermentation was
allowed to proceed for about 24 hours.
[0188] After fermentation the glucose concentration was below the
detection limit, the ethanol concentration was about 25 g/L, and
the xylose concentration was 30 g/L.
Purification of Ethanol and Xylose with SMB
[0189] Purification of a xylose stream obtained from enzymatic
hydrolysis of biomass that was fermented and clarified to remove
particulates has done by using simulated moving bed chromatography
(SMB). The system was optimized to deliver up to 100% recovery of
xylose and a 20-fold reduction in feed color, while incurring as
little as 1.76 fold dilution with xylose purity range of between
94-97%.
[0190] Approximation of SMB conditions was accomplished by
performing single column experiments known as pulse tests.
Conditions for any column size can be estimated using pulse test
data and the online Isocratic SMB Parameter Calculator available on
the Semba Biosciences website.
[0191] Simulated Moving Bed Chromatography unit: Semba Biosciences
SMB unit: model Octave 100 chromatography system with 4 Octave 100
pumps, capable of flow rate 0.0-100 ml/min, Control module,
Chromatography module and SembaPro software application.
[0192] Chromatography columns: Eight Kontes brand Chromaflex
jacketed columns 420870 series (2.5 cm ID, 30 cm length, 147 ml bed
volume) were used in the system.
[0193] Stationary phase: Dowex Monosphere 99 CA/320; Mitsubishi
Diaion UBK535.
[0194] Mobile phase (desorbent): DI water with resistivity of 5
M.OMEGA.cm or better.
[0195] A saccharified biomass from corn cob (CC) or wheat straw
(WS) was fermented producing a hydrolyzate mixture containing
xylose as the main component after the ethanol was distilled. The
hydrolyzate was centrifugation and pH was adjusted to between 6-7.
The hydrolyzate was then polish filtered in some cases to less
0.2-micron followed by concentration resulting in a solution
comprising of 40% to 50% dissolved solids. The xylose concentration
in this stream can be in the range of 160 to 225 g/L. The
concentrated xylose stream was then introduced into the SMB system
as the feed stream. A typical analysis for feed stream is provided
in table 1 below. Deionized water was introduced simultaneously as
the eluent stream.
[0196] The chromatography columns and system was preheated to
60.degree. C. Feed material was introduced to the SMB system at a
constant flow rate at ambient temperature. Eluent was
simultaneously pumped to the SMB system at a constant flow rate at
60 deg.C.
[0197] Xylose was enriched (more retained on the stationary phase)
in the extract and unknown dark colored by-product in the raffinate
(move more quickly with the mobile phase). Samples of extract
(xylose enriched stream) and raffinate (by-product stream) were
removed periodically in order to track the progress of the system
with respect to xylose recovery in the extract and xylose losses in
the raffinate.
[0198] Xylose yield can be expressed as % recovery in the extract
stream. Efficiency of the system is characterized in terms of
throughput and dilution of the feed.
[0199] Recovery of xylose in the extract was calculated as
follows:
(Xylose conc. of sample (g/L).times.flow rate of extract
(mL/min))/((xylose conc. of feed.times.flow rate feed (mL/min))
[0200] Losses to the raffinate were calculated as:
(Xylose conc. of sample (g/L).times.flow rate of raffinate
(mL/min))/((xylose conc. of feed.times.flow rate feed (mL/min))
[0201] Dilution of xylose in the extract was calculated once the
system reached steady state as follows:
Xylose conc. of extract sample (g/L)/xylose conc. of feed (g/L)
TABLE-US-00002 TABLE 1 Feed stream analysis Component Analysis
Solids 49.1% Xylose 226.6 g/L Cellobiose 4.6 g/L Lactose 11.8 g/L
Arabinose 8.4 g/L Glycerol 13.1 g/L Xylitol 3.6 g/L Phosphorus
300.6 ppm Sodium 5381.6 ppm Calcium 5411.6 ppm Sulfur 555.3 ppm
Silicon 78.1 ppm Potassium 14391.2 ppm Magnesium 267.0 ppm Acetic
acid 59.3 g/L
[0202] Any dilution incurred during the SMB purification introduces
water that ultimately would need to be removed from the system.
This extra water would need to be removed by distillation, which is
a very costly and high-energy procedure. Less dilution of the feed
hence requires less energy downstream.
[0203] The SMB process was manipulated/modified by changing column
conditions from a process that initially incurred relatively high
dilution of the feed stream. Product stream/feed stream ratio has
been reduced from 7.5 to 2.3. Similarly, the amount of waste stream
was also reduced from an initial waste stream/feed ratio of 7.2 to
an improved ratio of 1.2.
Biomass Produced L-Lactic Acid and Xylose Stream
[0204] Saccharified biomass made utilizing similar steps as
described above was used as the sugar source to produce a L-Lactic
acid xylose stream.
[0205] The glucose to L-Lactic acid fermenting organism
Lactobacillus rhamnosus NRRL B-445 was grown in 25 mL of MRS medium
(BD Diagnostic Systems No.: 288130) from 250 uL freezer stocks. The
culture was incubated overnight in a shaker incubator at 37.degree.
C. and 150-200 rpm.
[0206] Fermentation to produce the lactic acid was conducted in a
bioreactor equipped with a heating mantel, stifling impellors, pH
monitoring probes and temperature monitoring thermocouples.
[0207] The production medium for an experiment used 11 L of
saccharified biomass, 22 g of yeast extract, 1.6 mL of antifoam
AFE-0010, and 6% CaCO.sub.3. The media was heated to 70.degree. C.
for 1 hour and then cooled to 37.degree. C. The media was then
inoculated with 1% (110 mL) of the Lactobacillus rhamnosus.
Fermentation was allowed to proceed at 37.degree. C. while the
solution was stirred at 200 rpm. Glucose was completely consumed by
48 hours.
[0208] Subsequent to the fermentation, eight liters of the
unpurified fermentation product was heated at 90.degree. C. for
30-45 minutes and then cooled to room temperature. The cooled
mixture was acidified using concentrated sulfuric acid to between
pH 1.5 and 2 using pH strip indicators to monitor the pH. The
mixture was stirred at room temperature for 2 hours, during which
time a precipitate (e.g., including calcium sulfate) formed.
[0209] The suspension was centrifuged at 3400 rpm for 25 m and the
supernatant was filtered through a 0.22 .mu.m filter and 5.5 L of
filtrate was collected. Samples of the filtrate were collected for
analysis.
[0210] The filtrate was subsequently percolated through a column
containing 2.7 L of strongly acidic cation exchange resin,
Mitsubishi Diaion PK 228 in the acid form, at a flow rate of 1 bed
volume per hour (BV/h). The first liter of eluate was discarded.
The rest of the eluate was collected. Two liters of water were
added to the column after the filtrate had been added, and these
were also collected and combined with the eluate, providing 6.5 L
of combined eluate. The combined eluate was sampled for
analysis.
[0211] The combined eluate was subsequently concentrated utilizing
a rotary evaporator, providing 1.2 L of concentrate. A sample was
collected for analysis.
[0212] High Performance Liquid Chromatography (HPLC) was used to
analyze the L-lactic acid, xylose and acetic acid concentrations.
Inductively coupled plasma optical emission spectroscopy (ICP-OES)
was used to analyze the concentration of sulfur, iron, sodium,
calcium and magnesium. The analysis data is reported in Table
2.
TABLE-US-00003 TABLE 2 HPLC and ICP Analysis Pre SMB for Lactic
acid Fermentation Product Lactic Acetic ICP-OES Data - Sample Vol.
Xylose Acid Acid (Detection limit 10 ppm) Description (L) (g/L)
(g/L) (g/L) S Fe Mg Na Ca P Processed 5.5 34.402 62.409 7.208 1089
20 250 49 575 not medium done before PK228 Eluate from 6.5 27.188
49.476 5.666 741 <10 <10 384 <10 69 PK228 Concentrate 1.2
152.3 274.5 11.2 3662 <10 <10 1778 <10 358
Purification of L-Lactic Acid and Xylose Stream Utilizing SMB
[0213] Separation of lactic acid and xylose from lactic acid:xylose
mixtures was performed using Simulated Moving Bed Chromatography
(SMB) as described here.
Equipment and Analysis Methods
[0214] Simulated Moving Bed Chromatography unit: Semba Biosciences
SMB unit: model Octave 100 chromatography system with 4 Octave 100
pumps, capable of flow rate 0.0-100 ml/min, Control module,
Chromatography module and SembaPro software application.
[0215] Chromatography columns: Eight Kontes brand Chromaflex
jacketed columns 420870 series (2.5 cm ID, 30 cm length, 147 ml bed
volume) were used in the system.
[0216] Stationary phase: Mitsubishi Diaion UBK550.
[0217] Mobile phase (desorbent): 5 mM sulfuric acid prepared with
ACS grade sulfuric acid (98% .sup.w/.sub.w) and DI water with
resistivity of 5 M.OMEGA.cm or better.
[0218] Lactic acid separation efficiency in the extract can be
determined using High Performance Liquid Chromatography.
Chromatogram peak area analysis was used to calculate and express
percentage efficiency as follows:
1-(chromatogram peak area of xylose (Absorbance
units)/(chromatogram peak area of lactic acid (Absorbance
units)+chromatogram peak area of lactic acid dimer (Absorbance
units)))
[0219] Concentration of lactic acid in the Extract were determined
using standard analytical High Performance Liquid Chromatography
methodology referenced to an appropriate external standard sample
and is expressed in g L.sup.-1.
[0220] Xylose separation efficiency in the Raffinate was determined
using High Performance Liquid Chromatography. Chromatogram peak
area analysis was used to calculate and express percentage
efficiency as follows:
1-((chromatogram peak area of lactic acid (Absorbance
units)+chromatogram peak area of lactic acid dimer (Absorbance
units))/chromatogram peak area of xylose (Absorbance units)).
[0221] Concentration of xylose in the raffinate were determined
using standard analytical High Performance Liquid Chromatography
methodology referenced to an appropriate external standard sample
and is expressed in g L.sup.-1.
[0222] Losses to the raffinate were calculated as:
(Lactic acid concentration of sample (g L.sup.-1).times.flow rate
of Raffinate (mL min.sup.-1))/((lactic acid concentration of
Feed.times.Feed flow rate (mL min.sup.-1))
[0223] Dilution of lactic acid in the Extract was calculated once
the system reached steady state as follows:
Lactic acid concentration of extract sample (g L.sup.-1)/lactic
acid concentration of Feed (g L.sup.-1)
[0224] Dilution of xylose in the raffinate was calculated once the
system reached steady state as follows:
Xylose concentration of raffinate sample (g L.sup.-1)/xylose
concentration in Feed (g L.sup.-1)
Model Compound Study
[0225] Model mixtures of FCC grade lactic acid and FCC grade xylose
were prepared in ratios and concentrations representative of
fermentation derived lactic acid and xylose mixtures. These model
mixtures were employed to explore the design space using standard
multivariate analyses to determine SMB operational conditions.
[0226] The chromatography columns were maintained at ambient
temperature (24-28.degree. C.) during the experiments. Feed
material and desorbent were simultaneously introduced to the system
at a constant flow rate.
[0227] Lactic acid was enriched (more retained on the stationary
phase) in the extract and xylose enriched in the raffinate (less
retained on the stationary phase). Samples of extract (lactic acid
enriched stream) and raffinate (by-product stream) were removed
periodically in order to monitor the performance, e.g., the
separation efficiency.
[0228] Operational conditions were found to deliver any individual
separation efficiency of xylose or lactic acid (e.g., up to 100%),
or a simultaneous separation efficiency of xylose and lactic acid
of up to 96%. The dilution of lactic acid output can be selected at
any level from 1.99 fold to 233.83 fold dependent on operational
objectives.
Fermentation Derived Xylose and Lactic Acid Separation
[0229] The concentrates, derived from the fermentation of
saccharified material producing lactic acid and xylose mixtures,
were subjected to SMB for separation of the xylose and Lactic acid
in the mixtures.
[0230] Multiple experiments showed that lactic acid concentration
in such mixture ranged between about 135 to 300 g L.sup.-1, xylose
concentrations ranged from 77 to 230 g L.sup.-1 and the ratios of
lactic acid to xylose in this mixtures ranged from 1:0.55 to
1:0.88.
[0231] The lactic acid: xylose mixture streams from the concentrate
was introduced into the SMB system as the Feed stream while 5 mM
sulfuric acid was introduced simultaneously as the Desorbent
stream. Results from an experiment is listed in Table 3.
TABLE-US-00004 TABLE 3 Raffinate and Extract Results Dilution
Lactic Acid Xylose of Main Separation Concentration Concentration
Component Efficiency Starting 134.9 g L.sup.-1 76.6 g L.sup.-1 --
-- Material Extract 68.6 g L.sup.-1 6.0 g L.sup.-1 1.97 87.4%
Raffinate 0.6 g L.sup.-1 12.3 g L.sup.-1 6.25 97.0%
[0232] Xylose from the extract can be concentrated, for example, to
provide a concentrate such as a syrup or even xylose in a dry form.
Lactic acid obtained in the extract stream can be concentrated and
then subjected to a secondary, sequential SMB treatment to remove
later running, for example more polar, impurities. Following this,
additional concentration of the output lactic acid solution can be
required.
[0233] Once final concentration has been accomplished an orthogonal
purification technique can be applied to separate lactic acid from
residual sulfuric acid. Examples of suitable orthogonal techniques
include reactive distillation (e.g., distillation in the presence
of methanol to produce the more volatile methyl ester),
solvent--solvent extraction and sequential
derivitization--isolation--hydrolysis.
[0234] Other than in the examples herein, or unless otherwise
expressly specified, all of the numerical ranges, amounts, values
and percentages, such as those for amounts of materials, elemental
contents, times and temperatures of reaction, ratios of amounts,
and others, in the following portion of the specification and
attached claims may be read as if prefaced by the word "about" even
though the term "about" may not expressly appear with the value,
amount, or range. Accordingly, unless indicated to the contrary,
the numerical parameters set forth in the following specification
and attached claims are approximations that may vary depending upon
the desired properties sought to be obtained by the present
invention. At the very least, and not as an attempt to limit the
application of the doctrine of equivalents to the scope of the
claims, each numerical parameter should at least be construed in
light of the number of reported significant digits and by applying
ordinary rounding techniques.
[0235] Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the invention are approximations,
the numerical values set forth in the specific examples are
reported as precisely as possible. Any numerical value, however,
inherently contains error necessarily resulting from the standard
deviation found in its underlying respective testing measurements.
Furthermore, when numerical ranges are set forth herein, these
ranges are inclusive of the recited range end points (e.g., end
points may be used). When percentages by weight are used herein,
the numerical values reported are relative to the total weight.
[0236] Also, it should be understood that any numerical range
recited herein is intended to include all sub-ranges subsumed
therein. For example, a range of "1 to 10" is intended to include
all sub-ranges between (and including) the recited minimum value of
1 and the recited maximum value of 10, that is, having a minimum
value equal to or greater than 1 and a maximum value of equal to or
less than 10. The terms "one," "a," or "an" as used herein are
intended to include "at least one" or "one or more," unless
otherwise indicated.
[0237] Any patent, publication, or other disclosure material, in
whole or in part, that is said to be incorporated by reference
herein is incorporated herein only to the extent that the
incorporated material does not conflict with existing definitions,
statements, or other disclosure material set forth in this
disclosure. As such, and to the extent necessary, the disclosure as
explicitly set forth herein supersedes any conflicting material
incorporated herein by reference. Any material, or portion thereof,
that is said to be incorporated by reference herein, but which
conflicts with existing definitions, statements, or other
disclosure material set forth herein will only be incorporated to
the extent that no conflict arises between that incorporated
material and the existing disclosure material.
[0238] While this invention has been particularly shown and
described with references to preferred embodiments thereof, it will
be understood by those skilled in the art that various changes in
form and details may be made therein without departing from the
scope of the invention encompassed by the appended claims.
* * * * *