Process for producing ethanol from plant biomass using the fungus paecilomyces sp.

• US 4,840,903 A
• Filed: 08/08/1985
• Issued: 06/20/1989
• Est. Priority Date: 08/08/1985
• Status: Expired due to Fees

• Current Assignee: The United States of America As Represented By The Secretary of Agriculture
• Original Assignee: United States Department of Energy (Government of the United States of America)
• Inventors: Wu, Jung Fu
• Primary Examiner(s): Warren, Charles F.
• Application Number:
  US06/763,585
• Time in Patent Office: 1,412 Days
• Field of Search: 435/161, 435/163, 435/932, 435/165
• US Class Current: 435/165
• CPC Class Codes: C12N 1/145 Fungal isolates
• CPC Class Codes: C12P 7/10 substrate containing cellulosic material
• CPC Class Codes: C12R 2001/79 Paecilomyces
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel
• CPC Class Codes: Y10S 435/932 Paecilomyces

Abstract

A process for producing ethanol from plant biomass is disclosed. The process in cludes forming a substrate from the biomass with the substrate including hydrolysates of cellulose and hemicellulose. A species of the fungus Paecilomyces, which has the ability to ferment both cellobiose and xylose to ethanol, is then selected and isolated. The substrate is inoculated with this fungus, and the inoculated substrate is then fermented under conditions favorable for cell viability and conversion of hydrolysates to ethanol. Finally, ethanol is recovered from the fermented substrate.

Claims

1. A process for producing ethanol from plant biomass comprising:

forming a substrate from said biomass, said substrate including hydrolysates of cellulose and hemicellulose;

selecting and isolating a species of the fungus Paecilomyces sp. NF1 which species has the ability to ferment both cellobiose and xylose to ethanol;

inoculating said substrate with said selected fungus;

fermenting said inoculated substrate under conditions favorable for cell viability and conversion of hydrolysates to ethanol; and

recovering the ethanol from said substrate.

2. The process as claimed in claim 1, wherein the step of fermenting said substrate is carried out at a temperature ranging from about 20°

-42°

C.

3. The process as claimed in claim 2, wherein said temperature range comprises 30°

-37°

C.

4. The process as claimed in claim 1, wherein the pH of said inoculated substrate is maintained at about 2.2-7.0 during fermentation thereof.

5. The process as claimed in claim 1, wherein said biomass includes cellulose and hemicellulose, and wherein said substrate is formed by saccharification of said cellulose and hemicellulose.

6. The process as claimed in claim 5, wherein said saccharification step comprises acid hydrolysis.

7. The process as claimed in claim 5, wherein said saccharification step comprises enzymatic hydrolysis.

8. A process for producing ethanol from a substrate comprising:

forming a substrate selected from the group consisting of pentoses, hexoses, the disaccharides including sucrose, maltose, cellobiose and lactose, polysaccharides, and mixtures thereof;

inoculating said substrate with a species of the fungus Paecilomyces sp. NF1 species has the ability to ferment one or more of said, substrate components to ethanol;

fermenting said inoculated substrate under conditions favorable for cell viability and production of ethanol; and

recovering the ethanol from said fermented substrate.

9. The process as claimed in claim 8, wherein the fermentation of said inoculated substrate is carried out at a temperature ranging from about 20°

-42°

C.

10. The process as claimed in claim 8, wherein the pH of the inoculated substrate is about 2.2-7.0 during fermentation thereof.

11. The process as claimed in claim 8, wherein said pentoses are selected from the group consisting of D-xylose, D-ribose, L-arabinose, and mixtures thereof.

12. The process as claimed in claim 8, wherein said hexoses are selected from the group consisting of D-glucose, mannose, D-galactose, fructose, sorbose, and mixtures thereof.

13. The process as claimed in claim 8, wherein said disaccharide is selected from the group consisting of D-cellobiose, sucrose, maltose, lactose, and mixtures thereof.

14. The process as claimed in claim 8, wherein said polysaccharide comprises starch.

15. The process as claimed in claim 8, wherein said substrate comprises a mixture of at least xylose, glucose and cellobiose.

16. The process as claimed in claim 8, wherein said pentoses and hexoses are hydrolysate sugars of cellulose and hemicellulose.

17. A process for producing ethanol from a substrate having a least a portion thereof selected from the group consisting of cellobiose, xylose and mixtures thereof, said process comprising the steps of:

isolating a species of the filamentous fungus Paecilomyces sp. NF1 the ability to ferment both cellobiose and xylose to ethanol;

inoculating said substrate with the isolated fungus;

fermenting said inoculated substrate under conditions favorable for cell viability and conversion of any cellobiose and xylose present therein to ethanol; and

recovering the ethanol from said fermented substrate.

18. The process as claimed in claim 17, wherein the fermentation of said inoculated substrate is carried out at a temperature of about 20°

-42°

C.

19. The process as claimed in claim 17, wherein the pH of the inoculated substrate is approximately 2.2-7.0 during fermentation thereof.

20. The process as claimed in claim 17, wherein said substrate portion is derived by the acid hydrolysis of cellulose and hemicellulose.

21. The process as claimed in claim 17, wherein said substrate portion is derived by the enzymatic hydrolysis of cellulose and hemicellulose.

22. The process as claimed in claim 17, wherein said substrate comprises a mixture of at least xylose, cellobiose and glucose.

23. The process as claimed in claim 17, wherein said mixture is derived by the saccharification of cellulose and hemicellulose.

24. The process as claimed in claim 17, wherein said fermentation is carried out under aerobic conditions.

25. The process as claimed in claim 17, wherein said fermentation is carried out under anaerobic conditions. of ATCC No. 20766 and which is capable of assimilating both cellobiose and xylose to produce ethanol in recoverable amounts.

26. In a process for fermenting an aqueous fermentable sugars-containing solution to ethanol, the improvement comprising innoculating said solution with a species of the fungus Paecilomyces sp. NF1 which ferments sugars, to ethanol, and allowing fermentation to proceed.

27. The improvement as claimed in claim 26, wherein the fermentation is allowed to proceed until fermentation of the sugars present in said solution is substantially complete.