Methods for producing ethanol from carbon substrates

• US 20030180900A1
• Filed: 02/06/2003
• Published: 09/25/2003
• Est. Priority Date: 02/08/2002
• Status: Abandoned Application

• Current Assignee: Genencor International Incorporated (International Flavors & Fragrances Incorporated)
• Original Assignee: Genencor International Incorporated (International Flavors & Fragrances Incorporated)
• Inventors: Lantero, Oreste
• Application Number:
  US10/360,010
• Publication Number:
  US 20030180900A1
• Time in Patent Office: Days
• US Class Current: 435/160
• CPC Class Codes: C12P 7/06 Ethanol, i.e. non-beverage
• CPC Class Codes: C12P 7/10 substrate containing cellulosic material
• CPC Class Codes: C12P 7/18 polyhydric
• CPC Class Codes: C12P 7/20 Glycerol
• CPC Class Codes: C12P 7/44 Polycarboxylic acids
• CPC Class Codes: C12P 7/56 Lactic acid
• CPC Class Codes: C12P 7/58 Aldonic, ketoaldonic or saccharic acids uronic acids C12P19/00
• CPC Class Codes: C12P 7/60 2-Ketogulonic acid
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

The present invention provides means for the production of desired end-products of in vitro and/or in vivo bioconversion of biomass-based feed stock substrates, including but not limited to such materials as starch and cellulose. In particularly preferred embodiments, the methods of the present invention do not require gelatinization and/or liquefaction of the substrate. In particularly preferred embodiments, the present invention provides means for the production of ethanol.

Claims

1. A method for producing an alcohol as an end-product comprising the steps of:

a) contacting a carbon substrate and at least one substrate-converting enzyme to produce an intermediate; and

b) contacting said intermediate with at least one intermediate-converting enzyme, wherein said intermediate is substantially all converted by said intermediate enzyme to said alcohol.

2. The method of claim 1, wherein said intermediate-converting enzyme is a microbial enzyme.

3. The method of claim 2, wherein said intermediate-converting microbial enzyme is secreted by a microorganism in contact with said intermediate.

4. The method of claim 1, wherein said substrate-converting enzyme is a microbial enzyme.

5. The method of claim 4, wherein said substrate-converting microbial enzyme is secreted by a microorganism in contact with said substrate.

6. The method of claim 1, wherein said intermediate-converting enzyme and said substrate-converting enzyme are produced by microorganisms of the same species.

7. The method of claim 1, wherein said intermediate-converting enzyme and said substrate-converting enzyme are produced by microorganisms of the different species.

8. The method of claim 1, wherein concentration level of said intermediate is maintained at a level below that which triggers catabolite repression effects upon the conversion of said intermediate to said end-product.

9. The method of claim 1, wherein concentration level of said intermediate is maintained at a level below that which triggers enzymatic inhibition effects upon the conversion of said intermediate to said end-product.

10. The method of claim 1, wherein said intermediate is converted to said end-product at a rate sufficient to maintain the concentration of said at less than 0.25%.

11. The method of claim 1, wherein said substrate is selected from the group consisting of biomass and starch.

12. The method of claim 11, wherein said biomass comprises corn solids.

13. The method of claim 1, wherein said intermediate is selected from the group consisting of hexoses and pentoses.

14. The method of claim 13, wherein said hexose is glucose.

15. The method of claim 1, wherein said contacting said substrate and substrate-converting enzyme further comprises bioconverting said substrate to produce said intermediate.

16. The method of claim 1, wherein said alcohol end-product is ethanol.

17. The method of claim 1, wherein the step of contacting said substrate and said at least one substrate-converting enzyme further comprises providing an amount of said substrate-converting enzyme at a concentration that produces said intermediate at a concentration that is less than or equal to the amount of said intermediate converted by said at least one intermediate-converting enzyme.

18. The method of claim 1, wherein said at least one substrate-converting enzyme converts at least 50% of said substrate to said intermediate within 72 hours.

19. The method of claim 18, wherein said at least one substrate-converting enzyme converts at least 90% of said substrate to said intermediate within 72 hours.

20. The method of claim 19, wherein said at least one substrate-converting enzyme converts at least 95% of said substrate to said intermediate within 72 hours.

21. The method of claim 1, wherein said at least one substrate-converting enzyme and said at least one intermediate-converting enzyme are obtained from a microorganism selected from the group consisting of Rhizopus and Aspergillus.

22. A method for producing alcohol as an end-product comprising the steps of:

a) contacting a carbon substrate and at least one substrate-converting enzyme to produce an intermediate; and

b) contacting said intermediate with at least one intermediate-converting enzyme, wherein said intermediate is substantially all converted by said intermediate enzyme to said alcohol end-product, and wherein the presence of said end-product does not inhibit the further production of said alcohol end-product.

23. The method of claim 22, wherein said intermediate-converting enzyme is a microbial enzyme.

24. The method of claim 22, wherein said intermediate-converting microbial enzyme is secreted by a microorganism in contact with said intermediate.

25. The method of claim 22, wherein said substrate-converting enzyme is a microbial enzyme.

26. The method of claim 22, wherein said substrate-converting microbial enzyme is secreted by a microorganism in contact with said substrate.

27. The method of claim 22, wherein said intermediate-converting enzyme and said substrate-converting enzyme are produced by microorganisms of the same species.

28. The method of claim 22, wherein said intermediate-converting enzyme and said substrate-converting enzyme are produced by microorganisms of the different species.

29. The method of claim 22, wherein said alcohol end-product is ethanol.

30. A method for producing an alcohol end-product comprising the steps of:

a) contacting a carbon substrate and at least one substrate-converting enzyme to produce an intermediate; and

b) contacting said intermediate with at least one intermediate-converting enzyme, wherein said intermediate is substantially all converted by said intermediate enzyme to said alcohol end-product, and wherein the presence of said substrate does not inhibit the further production of said alcohol end-product.

31. The method of claim 30, wherein said intermediate-converting enzyme is a microbial enzyme.

32. The method of claim 30, wherein said intermediate-converting microbial enzyme is secreted by a microorganism in contact with said intermediate.

33. The method of claim 30, wherein said substrate-converting enzyme is a microbial enzyme.

34. The method of claim 30, wherein said substrate-converting microbial enzyme is produced is secreted by a microorganism in contact with said substrate.

35. The method of claim 30, wherein said intermediate-converting enzyme and said substrate-converting enzyme are produced by microorganisms of the same species.

36. The method of claim 30, wherein said intermediate-converting enzyme and said substrate-converting enzyme are produced by microorganisms of the different species.

37. The method of claim 36, wherein said alcohol end-product is ethanol.