Multi-enzyme product comprising glucoumylolytic, proteolytic and xylanolytic activities and process for preparing the same

Abstract

Enzyme preparation (I) produced by fermenting wheat bran with an Aspergillus niger strain has glucoamylase, protease and xylanase activities of at least 100 U / g (dry basis), provided that the glucoamylase activity is at least 750 U / g and / or the xylanase activity is at least 300 U / g. An Independent claim is also included for the production of (I) by: (1) moistening and pasteurizing or sterilizing wheat bran; (2) inoculating an at least 10 cm thick layer of the bran with Aspergillus niger; and (3) fermenting the bran in an aerated and periodically agitated reactor at 28 - 38 degrees C for 1 - 3 days while maintaining the moisture content of the bran at 50 - 60 wt.%.

Description

technical field

[0001] The present invention relates to a multi-enzyme product having glucoamylase, proteolytic ester and xylanase activities and a method for preparing the product by solid-state fermentation of wheat bran with the aid of Aspergillus niger. Background technique

[0002] It is known to produce ethanol from cornstarch by means of an enzymatic process comprising the steps of liquefying the starch with alpha-amylase to hydrolyze the starch to dextrins, followed by glucoamylase (also known as amyloglucosidase) Saccharification is performed to hydrolyze dextrins to glucose and finally to ferment glucose to ethanol.

[0003] The use of alpha-amylases and glucoamylases is generally satisfactory when starting from relatively pure starch emulsions obtained by wet grinding corn, but is used when it is desired to substitute wheat starch or flour for corn starch. Satisfactory results were not obtained with the two enzymes alone because the presence of hemicellulose incr...