Detoxifying and recycling of washing solution used in pretreatment of lignocellulose-containing materials

Patent metadata

Field	Value
Publication number	US-10072380-B2
Application number	US-201715496928-A
Country	US
Kind code	B2
Filing date	Apr 25, 2017
Priority date	Sep 3, 2007
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

The invention relates to a process of detoxifying pretreated lignocellulose-containing material comprising washing the pretreated lignocellulose-containing material in a washing solution and treating the used washing solution to remove an enzyme inhibitor and/or an inhibitor of a fermenting organism before recycling the used washing solution.

First claim

The invention claimed is:

1. A process for converting a lignocellulose-containing material into a hydrolyzate comprising mono- and oligosaccharides, the method comprising the steps of:
(a) subjecting a lignocellulose-containing material to a pretreatment;
(b) washing the pretreated lignocellulose-containing material in an aqueous washing solution;
(c) separating the pretreated and washed lignocellulose-containing material from the used washing solution, to obtain a pretreated and washed lignocellulose-containing material;
(d) removing an enzyme inhibitor and/or an inhibitor of a fermenting organism from the used aqueous washing solution obtained in step (c) by contacting the used aqueous washing solution obtained in step (c) with a column comprising a resin directly after washing and separating, and recycling the used aqueous washing solution with less enzyme inhibitor and/or less inhibitor of a fermenting organism to step (b);
(e) enzymatically hydrolyzing the separated lignocellulose-containing material obtained in step (c) resulting in at least partial hydrolysis of the cellulose and/or hemicellulose to obtain a hydrolyzate comprising mono- and/or oligosaccharides; and
(f) continuously repeating steps (a) to (e).

2. The process of claim 1 , wherein the lignocellulose-containing material originates from materials selected from the group consisting of: corn stover, corn fiber, hard wood, soft wood, cereal straw, switch grass, rice hulls, municipal solid waste, industrial organic waste, office paper, and mixtures thereof.

3. The process of claim 1 , wherein the lignocellulose-containing material is chemically and/or mechanically pretreated in step (a).

4. The process of claim 1 , wherein the lignocellulose-containing material is chemically pretreated in step (a), using an acid selected from the group consisting of sulphuric acid, acetic acid, citric acid, tartaric acid, and succinic acid, or mixtures thereof.

5. The process of claim 1 , wherein the lignocellulose-containing material is mechanically pretreated in step (a) at a high temperature and/or a high pressure.

6. The process of claim 1 , wherein the lignocellulose-containing material is subjected to hydrothermal pretreatment in step (a).

7. The process of claim 1 , wherein the lignocellulose-containing material is subjected to hydrothermal pretreatment in step (a) comprising high pressure in the range from 300 to 600 psi.

8. The process of claim 1 , wherein the lignocellulose-containing material is subjected to high temperature in step (a) in the range from about 100 to 300° C.

9. The process of claim 1 , wherein the lignocellulose-containing material is pretreated in step (a) by steam explosion, dilute acid steam explosion and/or wet oxidation.

10. The process of claim 1 , wherein the aqueous washing solution comprises a mixture of water and an organic solvent.

11. The process of claim 1 , wherein the resin comprises —NH 2 as a functional group.

12. The process of claim 1 , wherein the resin comprises —SO 3 , —COOH, —N+(CH 3 ) 3 , or —N(CH 3 ) 2 as a functional group.

13. The process of claim 1 , wherein the enzyme inhibitor and/or the inhibitor of the fermenting organism is selected from the group consisting of terpenes, aldehyde, polyhydroxy aromatics, 4-OH benzyl alcohol, 4-OH benzaldehyde, 4-OH benzoic acid, trimethyl benzaldehyde, 2-furoic acid, coumaric acid, ferulic acid, phenol, guaiacol, veratrole, pyrogallollol, pyrogallol mono methyl ether, vanillyl alcohol, vanillin, isovanillin, vanillic acid, isovanillic acid, homovanillic acid, veratryl alcohol, veratraldehyd, veratric acid, 2-O-methyl gallic acid, syringyl alcohol, syringaldehyde, syringic acid, trimethyl gallic acid, homocatechol, ethyl vanillin, creosol, p-methyl anisol, anisaldehyde, anisic acid, furfural, hydroxymethylfurfural, 5-hydroxymethylfurfural, formic acid, acetic acid, levulinic acid, cinnamic acid, coniferyl aldehyde, isoeugenol, hydroquinone, and combinations thereof.

14. The process of claim 1 , wherein the enzyme inhibitor and/or inhibitor of the fermenting organism is formic acid, acetic acid, or a combination thereof.

15. The process of claim 1 , wherein hydrolysis is carried out using one or more hydrolases selected from the group consisting of cellulase, hemicellulase, amylase, protease, esterase, endoglucanase, beta-glucosidase, cellobiohydrolase, cellobiase, xylanase, alpha-amylase, alpha-glucosidase, glucoamylase, proteases and lipases, or a mixture thereof.

16. The process of claim 15 , wherein the alpha-amylase is an acid amylase and/or a fungal alpha-amylase.

17. The process of claim 1 , wherein hydrolysis is carried out at a temperature between 25° C. and 70° C.

18. The process of claim 1 , wherein hydrolysis is carried out at a pH in the range from 3-8.

19. The process of claim 1 , wherein hydrolysis is carried out for between 12 and 96 hours.

Assignees

• Novozymes As
• Cofco Ltd
• Novozymes Als

Inventors

• Ren Haiyu
• Huang Hong Zhi
• Zheng Jie

Classifications

• D21C11/0042

  Fractionating or concentration of spent liquors by special methods (concentration by evaporation D21C11/10) · CPC title

• D21C9/02

  Washing {; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents} · CPC title

• D21C11/0007

  Recovery of by-products, i.e. compounds other than those necessary for pulping, for multiple uses or not otherwise provided for (volatile compounds obtained by decomposition of spent liquors in order to regenerate them D21C11/125; compounds obtained by fractionating the liquors in order to regenerate them D21C11/0042) · CPC title

• D21C5/005 Primary

  Treatment of cellulose-containing material with microorganisms or enzymes · CPC title

• D21C11/005 Primary

  Treatment of liquors with ion-exchangers · CPC title