Method for preparing β-galactosidase enzyme preparation by liquid fermentation of Bacillus subtilis

Abstract

The present invention relates to a method for preparing a beta-galactosidase preparation through liquid fermentation by using Bacillus subtilis. The method is characterized by comprising: selecting Bacillus subtilis F69 as a beta-galactosidase production strain, adopting a shake flask shocking method to ferment to prepare a fermentation broth or adopting a fermentation tank ventilation fermentation method to prepare a fermentation broth, and carrying out preparation of a beta-galactosidase preparation to obtain the beta-galactosidase preparation finished product. The produced beta-galactosidase has the following characteristics that: heat resistance is good, wherein the residual enzyme activity achieves 85% after thermal insulation for 60 min at a temperature of 80 DEG C; the enzyme activity is high, wherein the fermentation broth enzyme activity achieves 216 U / ml; and the enzyme recovery rate is high, wherein the total enzyme activity recovery rate is more than 80%, and the enzyme freeze-dried powder enzyme activity unit achieves 2512 U / g. In addition, the operation process is simple, the production efficiency is high, the production cost is low, and the method is suitable for mass production.

Description

technical field [0001] The invention relates to the technical field of bioengineering, in particular to a method for preparing a beta-galactosidase enzyme preparation by liquid fermentation of bacillus subtilis. Background technique [0002] β-galactosidase (EC3.2.1.23), also known as lactase, widely exists in various animals, plants and microorganisms, and its sources are very rich. Among them, lactic acid bacteria, Bacillus circulans, Escherichia coli, gas-producing enterobacteria, etc. in bacteria; Aspergillus oryzae, Aspergillus niger, Aspergillus carbonaceus, etc. in molds; , Candida tropicalis, etc.; Streptomyces coelicolor in actinomycetes all produce β-galactosidase. Due to the biological characteristics of rapid growth and efficient metabolism of microorganisms, they have become the main source of industrial enzyme preparations. β-galactosidase has important uses in the dairy industry: first, it can hydrolyze lactose in milk and other dairy products, and eliminate...

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Problems solved by technology

[0003] At present, β-galactosidase has been isolated from a variety of bacteria and fungi, but the β-galactosidase used in production has poor heat resistance, can only work at room temperature, and has a slow hydrolysis reaction rate. It takes a long time, and the fresh milk is easily contaminated by bacteria and deteriorates, which greatly limits its application range

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