Process for producing sugars from cellulosic biomass

• US 20090011474A1
• Filed: 06/20/2008
• Published: 01/08/2009
• Est. Priority Date: 06/20/2007
• Status: Abandoned Application

• Current Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Original Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Inventors: Balan, Venkatesh, Dale, Bruce E.
• Application Number:
  US12/214,687
• Publication Number:
  US 20090011474A1
• Time in Patent Office: Days
• US Class Current: 435/99
• CPC Class Codes: C12P 19/14 produced by the action of a carbohydrase (EC 3.2.x), e.g. by alpha-amylase , e.g. by cellulase, hemicellulase
• CPC Class Codes: C12P 7/06 Ethanol, i.e. non-beverage
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

A process for increasing production of sugars from cellulose in a plant biomass using ammonia after swelling of the biomass with water and enzymatic hydrolysis is described. The sugars are preferably fermented to an alcohol, particularly ethanol as a fuel for vehicles.

Claims

1. A process by which whole plants are harvested as a biomass and processed together as one unit so that sugars are generated and then optionally fermented to an alcohol which comprises:

(a) soaking the biomass in water for a period of time so as to increase the water within the biomass and to enhance sugar production from the biomass;

(b) treating the plant biomass with concentrated ammonia under pressure in a closed vessel and then relieving the pressure to provide a treated plant biomass with recovery of the ammonia;

(c) hydrolyzing the treated plant biomass in the presence of water to sugars using a combination of enzymes which hydrolyze cellulose, hemicellulose and other carbohydrates in the biomass to produce sugars; and

(d) optionally fermenting the sugars to produce the alcohol.

2. The process of claim 1 wherein the whole plant comprises both edible grain and non-edible (cell wall) portions of the plant.

3. The process of claim 2 wherein the whole plant is selected from the group consisting of corn, wheat and rice.

4. The process of claim 1 wherein plant cell wall rich portions and grains as the whole plants are harvested at the same time.

5. The process of any one of claims 1, 2, 3, or 4 wherein the biomass has a water content in step (d) of between about 0.1 and 2.0 kg water/kg of dry biomass.

6. The process of any one of claims 1, 2, 3, or 4 wherein the biomass is charged into the closed vessel reactor with the ammonia in an amount between about 0.2 and 2.0 kg of ammonia/kg of dry biomass.

7. The process of claim 1 wherein the temperature of the mixture of ammonia and the plant biomass in the closed vessel is between about 50°

C. and 200°

C.

8. The process of claim 1 wherein the biomass in the vessel is at a preselected temperature for a preselected time and then the pressure is released explosively causing disruption of the biomass.

9. The process of claim 8 wherein the pretreated biomass is processed to recover ammonia from the biomass.

10. The process of claim 1 wherein the sugars in step (c) are separated by filtering the water containing the sugars from the biomass.

11. The process of claim 1 wherein the sugars are produced from the biomass by cellulase, hemicellulase and amylase during the hydrolysis.

12. The process of claim 1 wherein amylase to hydrolyze starch and cellulases and hemicellulases to hydrolyze cell wall components are added in amounts to convert the carbohydrate to fermentable sugars.

13. The process of claim 1 wherein the alcohol is ethanol.

14. The process of claim 1 wherein the disruption of the biomass in step (c) is by an Ammonia Fiber Explosion (also called Ammonia Fiber Expansion) process (AFEX).

15. The process of claim 1 wherein in step (a) the absorbed ratio of water to biomass is in an amount of about 60 to 233 wt. % on a dry weight basis of the biomass and wherein a water to ammonia ratio is in a range of 0.6:

1 to 2.3;

3.

16. The process of claim 1 wherein the biomass is comminuted before or after the soaking in step (a).

17. The process of any one of claims 1, 2, 3, or 4 wherein in step (a) the soaking in water is with autoclaving.

18. The process of any one of claims 1, 2, 3, or 4 wherein a nonionic surfactant is provided with the enzymes in step (c) to increase the hydrolytic activity of the enzymes.

19. The process of any one of claims 1, 2, 3 or 4 wherein the biomass is washed after the treatment with the ammonia in step (b).