PROCESS FOR FERMENTING SUGARS CONTAINING OLIGOMERIC SACCHARIDES

• US 20090011481A1
• Filed: 03/16/2005
• Published: 01/08/2009
• Est. Priority Date: 03/31/2004
• Status: Active Grant

• Current Assignee: Cargill, Inc. (Agricultural Services Division)
• Original Assignee: NatureWorks LLC (Cargill, Inc. (Agricultural Services Division))
• Inventors: Reeder, David H., Beacom, Daniel R., Kolstad, Jeffrey J., Rush, Brian J.
• Granted Patent: US 9,328,364 B2
• Time in Patent Office: Days
• US Class Current: 435/139
• CPC Class Codes: C12P 19/02 Monosaccharides 2-ketogulonic acid C12P7/60
• CPC Class Codes: C12P 19/04 Polysaccharides, i.e. compounds containing more than five saccharide radicals attached to each other by glycosidic bonds
• CPC Class Codes: C12P 19/16 produced by the action of an alpha-1, 6-glucosidase, e.g. amylose, debranched amylopectin non-biological hydrolysis of starch C08B30/00
• CPC Class Codes: C12P 19/20 produced by the action of an exo-1,4 alpha-glucosidase, e.g. dextrose
• CPC Class Codes: C12P 7/56 Lactic acid

Abstract

Sugar mixtures containing nonfermentable oligomers are fermented in the presence of certain enzymes that depolymerise the oligomers simultaneously with the fermentation process.

Claims

1. A fermentation process for fermenting a starch hydrolysate containing 80-98 weight percent of glucose and 1-20 weight percent of glucose oligomers having a degree of polymerization of from 2 to 10, comprising forming a fermentation broth containing the starch hydrolysate if necessary fermenting the starch hydrolysate until the fermentation broth contains 30 g/L or less of glucose and from about 1 to about 25 g/L of one or more nonfermentable glucose oligomers, and then subjecting the fermentation broth to fermentation conditions in the presence of (A) a microorganism that ferments glucose but does not ferment said nonfermentable glucose oligomers and (B) an effective amount of at least one active enzyme that depolymerizes at least one of said nonfermentable glucose oligomers to form a glucose, under conditions such that the depolymerization of the nonfermentable glucose oligomers and the fermentation of the glucose occur simultaneously.

4. The process of claim 1, wherein the desired fermentation product is lactic acid.

2. A process for fermenting a fermentation substrate in the presence of a microorganism, comprising

(A) forming a starting fermentation broth containing (1) a fermentation substrate, of which (a) from about 75 to about 98% by weight is a monosaccharide that is fermentable by the microorganism to a desired fermentation product, and (b) from about 2 to about 25% by weight is one or more oligomeric saccharides that are not fermentable by the microorganism to the desired fermentation product, wherein the starting fermentation broth contains at least 30 g/L of the monosaccharide;

(B) fermenting the starting fermentation broth in the presence of the microorganism to conditions sufficient to ferment the monosaccharide and reduce the monosaccharide concentration in the fermentation broth to less than about 30 g/L;

(C) then adding to the fermentation broth active an effective quantity of at least one enzyme that depolymerizes at least one oligomeric saccharide in the fermentation broth to form a monosaccharide that is fermentable by the microorganism to form a desired fermentation product;

(D) and then subjecting the fermentation broth to conditions sufficient to simultaneously depolymerize at least one oligomeric saccharide and ferment monosaccharides to form the desired fermentation product.

5. The process of claim 2, wherein the oligomeric saccharides have a degree of polymerization of from 2 to 5.

6. The process of claim 5, wherein the desired fermentation product is lactic acid.

7. The process of claim 6 wherein the oligomeric saccharides are oligomers of glucose.

3. (canceled)