Mutant of pectin lyase from Aspergillus niger and viscosity reducer of corn syrup in alcohol fermentation production

Abstract

The invention provides an aspergillus niger pectin lyase mutant and a viscosity reducer for syrup during corn ethanol fermentation production, and relates to the field of biotechnologies. Lysine at the 241st positions of amino acid sequences of aspergillus niger pectin lyase is replaced by methionine to obtain the mutant. The invention further provides an encoding gene of the mutant. A method for preparing the mutant includes fermenting Escherichia coli with the encoding gene of the mutant to obtain the mutant. The viscosity reducer for the syrup during corn ethanol fermentation production is a mixture of the mutant and one or two types of cellulase, xylanase, beta-glucanase, mannanase, glutamine transaminase and lipase. The aspergillus niger pectin lyase mutant, the viscosity reducer and the encoding gene have the advantages that the aspergillus niger pectin lyase mutant is excellent in enzyme stability and catalytic activity, and the method for preparing the aspergillus niger pectin lyase mutant is simple; the viscosity of the syrup can be quickly and efficiently reduced by the viscosity reducer during corn ethanol fermentation production under the condition of low energy consumption.

Description

technical field [0001] The invention relates to the field of biotechnology, in particular to a mutant of Aspergillus niger pectin lyase and a viscosity reducer for syrup in corn alcohol fermentation production. Background technique [0002] There are two types of corn distillers grain protein feed products on the market: one is DDG (Distillers Dried Grains), which is a feed obtained by simply filtering corn distillers grains, drying the filter residue, draining the filtrate, and drying the filter residue alone; One is DDGS (Distillers Dried Grains with Solubles) feed, that is, dried distiller's grains containing soluble solids, which is obtained by drying and concentrating the filtrate and then mixing and drying the filter residue. The energy and total nutrients of the latter are significantly higher than the former. [0003] The distiller's waste mash after corn alcohol fermentation is centrifuged or plate-and-frame filtered to obtain wet distiller's grains (WDG) and super...

AI Technical Summary

Problems solved by technology

Due to the low concentration of syrup, a large amount of water is brought in, which greatly increases the energy consumption of feed drying steam, raises the drying temperature, prolongs the high temperature residence time, destroys a large amount of nutrients, and produces a large amount of Maillard reaction, which makes DDGS darker. , it is easy to have a burnt smell, which affects the palatability of animals, and finally affects the grade and price of DDGS feed, reducing the profits of corn fuel ethanol enterprises

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