PROCESS OF PRODUCING A FERMENTATION PRODUCT

FIELD OF THE INVENTION

The present invention relates to methods of producing fermentation products, dextrins, and sugars from a starch-containing material.

BACKGROUND ART

A vast number of commercial products that are difficult to produce synthetically are today produced by fermentation. Such products include alcohols (e.g., ethanol, methanol, butanol, 1,3-propanediol); organic acids (e.g., acetic acid, citric acid, itaconic acid, gluconic acid, lactic acid, succinic acid, 2,5-diketo-D-gluconic acid); ketones (e.g., acetone); amino acids (e.g., glutamic acid); gases (e.g., H₂ and CO₂), and more complex compounds, including, for example, antibiotics (e.g., penicillin and tetracycline); enzymes; vitamins (e.g., riboflavin, B₁₂, beta-carotene); and hormones. Fermentation is also commonly used in the consumable alcohol (e.g., beer and wine), dairy (e.g., in the production of yogurt and cheese), leather, and tobacco industries.

A vast number of processes of producing fermentation products, such as ethanol, by fermentation of sugars provided by degradation of a starch-containing material are known in the art.

However, production of fermentation products from such plant materials is still too costly. Therefore, there is a need for providing processes that can increase the yield of the fermentation product and thereby reducing the production costs.

US 2003/0145347 discloses a method of processing grain such as corn and soybeans, utilizing thioredoxin and/or thioredoxin reductase to enhance extractability and recovery of starch and protein.

It is an object of the present invention to provide an improved process for producing a fermentation product.

SUMMARY OF THE INVENTION

The present invention relates to a process of producing a fermentation product, comprising:

(a)        grinding a starch-containing material that has not been wet milled to produce a ground starch-containing material;

(b)        liquefying the ground starch-containing material with an alpha-amylase to produce a liquefied starch-containing material comprising a dextrin;

(c)        saccharifying the liquefied starch-containing material with a saccharifying enzyme to produce a saccharified material comprising a sugar; and

(d)        fermenting the saccharified material with a fermenting organism;

wherein the starch-containing material is treated with a thioredoxin prior to or during grinding, the ground starch-containing material is treated with a thioredoxin prior to or during liquefaction, the liquefied starch-containing material is treated with a thioredoxin prior to or during saccharification, and/or the saccharified material is treated with a thioredoxin prior to or during fermentation.

In another embodiment, the invention relates to a process of producing a fermentation product comprising the steps of:

(a)        grinding a starch-containing material that has not been wet milled to produce a ground star...