PROCESS FOR ALCOHOLIC FERMENTATION OF LIGNOCELLULOSIC BIOMASS

• US 20100159552A1
• Filed: 12/22/2009
• Published: 06/24/2010
• Est. Priority Date: 12/23/2008
• Status: Active Grant

• Current Assignee: GreenField Specialty Alcohols Inc.
• Original Assignee: GreenField Ethanol Inc.
• Inventors: Benech, Régis-Olivier, BENSON, Robert Ashley Cooper
• Granted Patent: US 8,642,303 B2
• Time in Patent Office: Days
• US Class Current: 435/165
• CPC Class Codes: C12P 7/10 substrate containing cellulosic material
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

A process for the production of ethanol wherein a hydrolyzed lignocellulosic biomass is fermented in the presence of a stillage residue. The fermentation of cellulosic hydrolysates is improved by adding prior to and/or during fermentation a stillage residue side stream from a corn starch-to-ethanol process as a nutrient source for the yeast organisms used in the fermentation. Stillage residues from the grain dry mill ethanol producing process, including the whole stillage, wet cake, thin stillage, and/or syrup are added to assist as a nitrogen and nutrient source for the fermentive processes. The stillage residue is produced by any grain-to-ethanol process.

Claims

1. A process for the production of ethanol, the process comprising the step of fermenting a hydrolyzed lignocellulosic biomass in the presence of a stillage residue, the stillage residue is produced by a whole grain starch-to-ethanol process.

2. The process of claim 1, wherein the stillage residue is selected from the group consisting of whole stillage, thin stillage, wetcake, syrup, and any combination thereof.

3. The process of claim 1, further comprising a propagation step whereby yeast is conditioned and grown prior to the step of fermentation.

4. The process of claim 1, wherein the hydrolyzed lignocellulosic biomass is produced by acid pre-treatment wherein the acid catalyst is a mineral acid or a carboxylic acid.

5. The process of claim 1, wherein the hydrolyzed lignocellulosic biomass is selected from the group consisting of agricultural residues, purpose grown crops, woody biomass, and any combination thereof.

6. The process of claim 1, wherein the hydrolyzed lignocellulosic biomass is obtained from corn cobs.

7. The process of claim 1, wherein the ethanol is produced by fermentation with a ethanologenic organism.

8. The process of claim 7, wherein the ethanologenic organism is a prokaryotic organism.

9. The process of claim 8, wherein the ethanologenic organism is selected from the group consisting of Escherichia coli, Klebsiella oxytoca, and Zymomonas mobilis, Clostridium thermocellum.

10. The process of claim 7, wherein the ethanologenic organism is a eukaryotic organism.

11. The process of claim 10, wherein the eukaryotic organism is selected from the group consisting of Saccharomyces cerevisia, Pichia stipitis.

12. A process for the propagation of yeast, the process comprising the step of propagating yeast in the presence of a stillage residue from a whole grain starch-to-ethanol process.

13. The process of claim 12, wherein the stillage residue is selected from the group consisting of whole stillage, thin stillage, wetcake, syrup, and any combination thereof.

14. A process for the production of cellulosic ethanol from lignocellulosic biomass, comprising the steps of:

Pretreating the lignocellulosic biomass to decompose the lignocellulosic biomass into fibrous solids;

Hydrolyzing the fibrous solids with enzymes to produce cellulose sugars; and

fermentating the cellulose sugars in the presence of a stillage residue from a whole grain starch-to-ethanol dry mill process.

15. The process of claim 14, wherein the stillage residue is selected from the group consisting of whole stillage, thin stillage, wetcake, syrup, and any combination thereof.

16. The process of claim 14, wherein the step of pretreating the lignocellulosic biomass includes process conditions including the step of exposing the lignocellulosic biomass to steam in a reaction vessel at an elevated temperature and reaction pressure for a preselected exposure time, and releasing the reaction pressure for explosive decomposition of the lignocellulosic bioimass.

17. The process of claim 16, wherein the elevated temperature is in the range of 190-210°

Celsius, the reaction pressure is between 190 to 275 psig, and the preselected exposure time is between 3 to 10 minutes.

18. The process of claim 16, wherein the elevated temperature is 205 degrees Celsius, the reaction pressure is 235 psig, and the preselected exposure time is 8 minutes.

19. The process of claim 17, wherein the pressure is released within less than 1000 milliseconds.

20. The process of claim 17, wherein the pressure is released within 300 milliseconds.

21. The process of claim 16, wherein the process conditions are selected for the achievement of a severity index of 3.9 to 4.1.

22. The process of claim 21, wherein the severity index is 4.0.

23. The process of claim 14, wherein the enzymatic hydrolysis is carried out at 10-30% consistency, and at a temperature of 40-60°

Celsius and a pH 4.5 to 5.5.

24. The process of claim 14, wherein the fermentation step is carried out at 10-30% consistency, 30-37°

C. and a pH of 5.2 to 5.9.

25. The process of claim 14, wherein the enzymatic hydrolysis of solids generated during the pressure release steps is carried out at a temperature of 50°

C., pH 5.0 until completion.

26. The process of claim 14, wherein the fermentation step is carried out at a temperature of 35°

C., and at a pH of 5.3 until completion.

27. The process of claim 14, further comprising a process arrangement step for step of collecting and processing fermentation products for distilling fuel grade ethanol.

28. The process of claim 27, wherein the process arrangement step for distilling fuel grade ethanol includes a distillation portion, a condensation and dehydration portion, a separation and drying portion and an evaporation portion.

29. The process of claim 28, wherein the process arrangement produces hot ethanol vapor and thin stillage.