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BR-112019007921-B1 - Methods for Reducing Foam During Ethanol Fermentation

BR112019007921B1BR 112019007921 B1BR112019007921 B1BR 112019007921B1BR-112019007921-B1

Abstract

The invention relates to methods for reducing foam during ethanol fermentation by adding a phospholipase A and/or a phospholipase C during fermentation.

Inventors

  • Kim Borch
  • Justin Schroeder
  • Xinyu Shen

Assignees

  • NOVOZYMES A/S

Dates

Publication Date
20260310
Application Date
20171017
Priority Date
20161017

Claims (3)

  1. 1. Method for reducing foam during ethanol fermentation characterized by a phospholipase A and a phospholipase C being present and/or added during fermentation; wherein said phospholipase A is the mature part of the sequence shown as SEQ ID NO: 2; wherein said phospholipase C is the mature part of the sequence shown as SEQ ID NO: 7.
  2. 2. Process for producing ethanol characterized by comprising: (a) converting a starch-containing material into dextrins with an alpha-amylase; (b) saccharifying the dextrins using a carbohydrate-generating enzyme to form fermentable sugars; (c) fermenting the fermentable sugars into ethanol using a fermenting organism; wherein a phospholipase A and a phospholipase C are present and/or added during steps (b) and/or (c), wherein said phospholipase A is the mature part of the sequence shown as SEQ ID NO: 2; wherein said phospholipase C is the mature part of the sequence shown as SEQ ID NO: 7.
  3. 3. Use of a phospholipase A and a phospholipase C characterized by being to reduce foam formation during ethanol fermentation, wherein said phospholipase A is the mature part of the sequence shown as SEQ ID NO: 2 and phospholipase C is the mature part of the sequence shown as SEQ ID NO: 7.

Description

FIELD OF THE INVENTION [0001] The present invention relates to methods for reducing foam during ethanol fermentation and to processes for producing ethanol that include a foam-free fermentation step using a method of the invention. BACKGROUND OF THE INVENTION [0002] Ethanol for use as fuel is typically produced by first grinding starch-containing material in a dry grinding or wet milling process, then degrading the material into fermentable sugars using enzymes, and finally converting the sugars directly or indirectly into the desired fermentation product using a fermenting organism. Ethanol can be recovered from fermented wort (often referred to as "hopped wort"), for example, by distillation, which separates the ethanol from other liquids and/or solids. [0003] The document in WO 2008/135547 refers to foam reduction in processes for the production of a fermentation product by placing the fermentation medium comprising a fermenting organism in contact with a lipolytic enzyme selected from the group consisting of phospholipase, lyso-phospholipase and lipase and with a metallic salt. [0004] The document in WO 2014/147219 refers to a phospholipase A from Talaromyces leycettanus. [0005] The document in WO2015/140275 reveals a phospholipase C from Bacillus thuringiensis. [0006] Foam generation during ethanol fermentation is a major problem, especially in ethanol production processes where starch-containing material is liquefied with an alpha-amylase and a protease before saccharification and fermentation. [0007] Therefore, there is a desire to reduce foam in ethanol fermentation. SUMMARY OF THE INVENTION [0008] The object of the present invention is to provide methods for reducing foam in a fermentation medium during ethanol fermentation, wherein fermentable sugars are converted into ethanol by a fermenting organism, such as yeast. The invention also relates to processes for producing ethanol from starch-containing material using an antifoaming method of the invention. [0009] The inventor surprisingly found that by adding phospholipase A from Talaromyces leycettanus (SEQ ID NO: 2) and/or phospholipase C from Bacillus thuringiensis (SEQ ID NO: 7), the foam generated before and/or during ethanol fermentation can be reduced or avoided. Foam is especially a problem when ethanol fermentation is carried out using yeast in a fermentation medium comprising fermentable sugars derived from starch-containing material that has been liquefied in the presence of an alpha-amylase and a protease prior to saccharification and ethanol fermentation. [0010] Therefore, in the first aspect, the invention relates to methods for reducing foam during ethanol fermentation, wherein a phospholipase A and/or a phospholipase C are present and/or are added during fermentation. [0011] In one embodiment, phospholipase (or phospholipases) is added to the yeast propagation tank. [0012] In a preferred embodiment, phospholipase A is the mature part of the sequence presented as SEQ ID NO: 2 or a sequence that has sequence identity with the same of at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%. [0013] In one embodiment, phospholipase A is derived from a Talaromyces strain, in particular, Talaromyces leycettanus. Phospholipase A may be a phospholipase A1 classified under E.C. 3.1.1.32. [0014] In a preferred embodiment, phospholipase C is the mature part of the sequence presented as SEQ ID NO: 7, or a sequence that has sequence identity with the same of at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%. [0015] In one embodiment, phospholipase C is derived from a strain of Bacillus, in particular, Bacillus thuringiensis. Phospholipase C may be classified under E.C. 3.1.4.3. [0016] In one embodiment, phospholipase A presented in SEQ ID NO: 2 and phospholipase C presented in SEQ ID NO: 7 may be present and/or added during fermentation. [0017] In another aspect, the invention relates to processes for producing ethanol comprising (a) converting a starch-containing material into dextrins with an alpha-amylase; (b) saccharifying the dextrins using a carbohydrate-generating enzyme, in particular, a glucoamylase, to form fermentable sugars; (c) fermenting the fermentable sugars into ethanol using a fermenting organism; wherein phospholipase A and/or phospholipase C are present and/or added during steps (b) and/or (c). [0018] In a preferred embodiment, phospholipase A, for example, a derivative of a Talaromyces strain, in particular, Talaromyces leycettanus, is the mature part of the sequence presented as SEQ ID NO: 2, or one that has a sequence identity with the same of at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at lea