Process for alcoholic fermentation of lignocellulosic biomass

• US 8,642,303 B2
• Filed: 12/22/2009
• Issued: 02/04/2014
• Est. Priority Date: 12/23/2008
• Status: Active Grant

• Current Assignee: GreenField Specialty Alcohols Inc.
• Original Assignee: GreenField Specialty Alcohols Inc.
• Inventors: Benson, Robert Ashley Cooper, Benech, Regis-Olivier
• Primary Examiner(s): Ware, Debbie K
• Application Number:
  US12/644,935
• Publication Number:
  US 20100159552A1
• Time in Patent Office: 1,505 Days
• Field of Search: None
• 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 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,

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 biomass,

wherein the process conditions are selected for the achievement of a severity index of 3.9 to 4.1.

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, 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.

4. The process of claim 1, wherein the elevated temperature is 205 degrees Celsius, the reaction pressure is 235 psig, and the preselected exposure time is 8 minutes.

5. The process of claim 3, wherein the pressure is released within less than 1000 milliseconds.

6. The process of claim 3, wherein the pressure is released within 300 milliseconds.

7. The process of claim 1, wherein the severity index is 4.0.

8. The process of claim 1, 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.

9. The process of claim 1, wherein the fermentation step is carried out at 10-30% consistency, 30-37°

C. and a pH of 5.2 to 5.9.

10. The process of claim 1, wherein the enzymatic hydrolysis of solids is carried out at a temperature of 50°

C., pH 5.0 until completion.

11. The process of claim 1, wherein the fermentation step is carried out at a temperature of 35°

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

12. The process of claim 1, further comprising a process arrangement step for step of collecting and processing fermentation products for distilling fuel grade ethanol.

13. The process of claim 12, 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.

14. The process of claim 13, wherein the process arrangement produces hot ethanol vapor and thin stillage.