Methods of using cellulase for reducing the viscosity of feedstock
The invention provides methods for treatment of feedstock to reduce the relative viscosity and promote release of fermentable sugars.
1. A method of decreasing the relative viscosity of feedstock comprising:
incubating the feedstock with about 0.01 FPU to about 20 FPU cellulase/g dry weight of feedstock for about 10 minutes to about 10 hours at a pH of about 2 to about 6 at a temperature of about 40° C. to about 80° C., said feedstock, prior to treatment, having a relative viscosity of at least 20,000 cP;
thereby decreasing the relative viscosity of the feedstock.
2. The method of claim 1 , wherein the feedstock is a bagasse, corn fiber, corn stover, a plant waste material, a processing or agricultural byproduct, a sugar cane, monoenergy cane, sorghum sudan, Miscanthus , switchgrass, wheat, milo, bulgher, barley, rice, corn, beet, or tree.
3. The method of claim 1 , wherein the feedstock is incubated with about 0.05 FPU to about 20 FPU cellulase/g dry weight of feedstock.
4. The method of claim 1 , wherein the feedstock is incubated for about 10 minutes to about 6 hours.
5. The method of claim 1 , wherein the relative viscosity after treatment is less than 8000 cP.
6. The method of claim 1 , wherein the pH is about 3 to 6.
7. The method of claim 6 , wherein the feedstock is incubated for about 10 minutes to about 6 hours.
8. The method of claim 6 , wherein the relative viscosity after treatment is less than 8000 cP.
9. The method of claim 1 , wherein the feedstock is incubated at a temperature of: about 45° C. to about 80° C.
10. The method of claim 9 , wherein the feedstock is incubated for about 10 minutes to about 6 hours.
11. The method of claim 9 , wherein the relative viscosity after treatment is: less than 8000 cP.
12. The method of claim 1 , wherein the feedstock is pretreated in an acidic solution prior to incubation with cellulase.
13. The method of claim 12 , wherein the acidic solution is phosphoric acid or sulfuric acid.
14. The method of claim 13 , wherein the phosphoric acid solution comprises about 0.01% (w/w) to about 10% (w/w) phosphoric acid.
15. The method of claim 13 , wherein the sulfuric acid solution comprises about 0.01% (w/w) to about 10% (w/w) sulfuric acid.
16. The method of claim 12 , wherein the feedstock is pretreated in an acidic solution for about 2 minutes to about 2 hours.
17. The method of claim 1 , wherein the feedstock is pretreated with steam for about 1 hour to about 3 hours prior to treatment with cellulase.
18. The method of claim 17 , wherein the feedstock is treated with steam after treatment with an acidic solution.
19. The method of claim 18 , wherein the feedstock prior to treatment comprises a mixture solution of about 8-12% dry weight in an aqueous solution.
20. The method of claim 1 , wherein the method decreases relative viscosity of the feedstock by at least 50% as compared to the starting material and/or extracts at least about 40% of fermentable sugars found in the feedstock.
21. The method of claim 20 , wherein the fermentable sugars comprise one or more of xylose, galactose, and arabinose.
22. The method of claim 1 , wherein said method extracts fermentation inhibitors from said feedstock in an amount less than 1% of the volume of the incubation mixture formed by the mixture of feedstock with cellulase.
23. The method of claim 22 , wherein the fermentation inhibitors comprise one or more of furfural, hydroxymethylfurfural, formate, and acetate.
24. A method of decreasing the relative viscosity of feedstock comprising:
incubating the feedstock with about 0.50 FPU to about 5 FPU cellulase/g dry weight of feedstock cellulase for about 15 minutes to about 2 hours; wherein the feedstock is incubated at a pH of about 3 or less at a temperature of at least 60° C. and the feedstock, prior to treatment, has a relative viscosity of at least 20,000 cP;
thereby decreasing the relative viscosity of the feedstock and the relative viscosity after treatment is less than 1500 cP.
25. A method of reducing the viscosity of a feedstock having a viscosity of at least 20,000 cP comprising:
combining the feedstock having a viscosity of at least 20,000 cP with a feedstock obtained by treating a feedstock by the method of claim 1 , wherein the feedstock having a viscosity of at least 20,000 cP comprises 30% or less of the volume of the feedstock treated by the method of claim 1 .