Process for making fuels and chemicals from AFEX-treated whole grain or whole plants

• US 20090053771A1
• Filed: 08/21/2008
• Published: 02/26/2009
• Est. Priority Date: 08/22/2007
• 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: Bals, Bryan, Dale, Bruce, Chundawat, Shishir, Balan, Venkatesh
• Application Number:
  US12/229,225
• Publication Number:
  US 20090053771A1
• Time in Patent Office: Days
• US Class Current: 435/72
• 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 7/10 substrate containing cellulosic material
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

A process for hydrolyzing whole grain or whole plant biomass after an Ammonia Fiber Explosion (AFEX) process step is described. The process preferably uses a biomass that is hydrolyzed using a different combination of enzymes (amylase, cellulase and hemicellulase) to sugars for fermentation to produce ethanol. Harvesting the whole plant inclusive of grains and stalk for ethanol bio-processing is an economical route for future biorefineries. In addition to sugars, various value-added products like proteins and oil can be co-generated.

Claims

1. A process for producing sugars from plant biomass, the process comprising:

(a) providing a comminuted plant biomass comprising cellulose, hemicellulose, and starch;

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

(c) hydrolyzing the treated plant biomass in the presence of water to form sugars using a combination of enzymes which hydrolyze the cellulose, the hemicellulose, and the starch to produce the sugars, the enzymes comprising an amylase and a cellulase.

2. The process of claim 1, wherein the plant biomass is selected from the group consisting of corn, wheat, rice, and combinations thereof.

3. The process of claim 2, wherein the plant biomass comprises corn silage.

4. The process of claim 1, wherein the plant biomass is a whole plant comprising an edible grain of the plant and a lignocellulosic portion of the plant, the edible grain and the lignocellulosic portion of the plant having been harvested at the same time.

5. The process of claim 1, wherein:

(i) the plant biomass has a water content in step (c) ranges from about 0.1 kg and 2 kg water/kg of dry plant biomass;

(ii) the plant biomass is contacted with the ammonia in step (b) in an amount ranging from about 0.2 kg and 2 kg of ammonia/kg of dry plant biomass; and

(iii) the temperature of the mixture of the ammonia and the plant biomass in the closed vessel in step (b) ranges from about 50°

C. and 150°

C.

6. The process of claim 1, wherein step (b) further comprises:

(b-1) maintaining the closed vessel at a preselected temperature for a preselected time and an elevated pressure ranging from about 100 psi to 500 psi, and then

(b-2) explosively releasing the pressure from the closed vessel, thereby causing disruption of the biomass by the ammonia.

7. The process of claim 1, further comprising:

(d) filtering the water from the hydrolyzed plant biomass to separate and recover the formed sugars.

8. The process of claim 1, wherein the enzymes in step (c) further comprise a hemicellulase.

9. The process of claim 8, wherein:

(i) the amylase comprises one or more of α

-amylase and glucoamylase;

(ii) the cellulase comprises one or more of endocellulase, exocellulase, and β

-glucosidase; and

(iii) the hemicellulase comprises one or more of xyloglucanase, β

-xylosidase, endoxylanase, α

-L-arabinofuranosidase, α

-glucuronidase, and acetyl xylan esterase.

10. The process of claim 1, wherein the combination of enzymes comprises about 1 mg amylase/g glucan to about 100 mg amylase/g glucan and about 1 mg cellulase/g glucan to about 100 mg cellulase/g glucan.

11. The process of claim 1, wherein the combination of enzymes comprises a first enzyme and a second enzyme, and step (c) further comprises:

(c-1) adding the first enzyme to the treated plant biomass and allowing the first enzyme to hydrolyze the treated plant biomass for a first preselected time, and then

(c-2) adding the second enzyme to the treated plant biomass and allowing the second enzyme to hydrolyze the treated plant biomass for a second preselected time.

12. The process of claim 11, wherein the first enzyme comprises an amylase to hydrolyze starch in the treated plant biomass and the second enzyme comprises a cellulase to hydrolyze cell wall components in the treated plant biomass.

13. The process of claim 12, wherein the first enzyme is deactivated prior to adding the second enzyme to the treated plant biomass.

14. The process of claim 1, further comprising:

(d) fermenting the sugars, thereby forming ethanol.

15. A process for producing a fermentation product from a whole-plant biomass processed as a unit, the process comprising:

(a) providing a monocot whole-plant biomass comprising an edible grain of the plant biomass and a lignocellulosic portion of the plant biomass, the edible grain and the lignocellulosic portion of the plant biomass having been harvested at the same time;

(b) treating the monocot whole-plant biomass with ammonia under pressure and then rapidly releasing the pressure to provide a disrupted cellulosic plant biomass;

(c) hydrolyzing the disrupted cellulosic plant biomass to form sugars using a combination of enzymes comprising an amylase and a cellulase; and

(d) fermenting the formed sugars to produce a fermentation product.

16. The process of claim 15, wherein step (b) comprises performing an Ammonia Fiber Explosion (Expansion) process (AFEX).

17. The process of claim 15, wherein the monocot whole-plant biomass is soaked in water or a dilute combination of water and ammonia for a period of time prior to the treatment in step (b) to enhance sugar production.

18. The process of claim 15, wherein the fermentation product comprises ethanol.

19. The process of claim 15, wherein the enzymes in step (c) further comprise a hemicellulase.

20. A process for producing sugars from whole-plant biomass, the process comprising:

(a) providing a comminuted whole-plant biomass selected from the group consisting of corn, wheat, rice, and combinations thereof, the whole-plant biomass comprising an edible grain of the plant biomass and a lignocellulosic portion of the plant biomass, the edible grain and the lignocellulosic portion of the plant biomass having been harvested at the same time;

(b) treating the whole-plant biomass with about 0.2 kg to 2 kg of ammonia/kg of dry plant biomass in a closed vessel at an elevated pressure ranging from about 100 psi to 200 psi and an elevated temperature ranging from about 50°

C. to 100°

C. for a preselected time, and then explosively releasing the pressure to provide a disrupted cellulosic plant biomass;

(c) hydrolyzing the disrupted cellulosic plant biomass to form sugars with enzymes comprising (i) an amylase to hydrolyze starch in the treated whole-plant biomass and (ii) a cellulase to hydrolyze cell wall components in the treated whole-plant biomass, thereby producing the sugars.