Bacillus subtilis capable of expressing beta-mannase at high efficiency, as well as enzyme product and production method thereof

Abstract

The invention provides a bacillus subtilis TQBm strain capable of expressing beta-mannase at high efficiency. The bacillus subtilis TQBm strain is prepared by inducing culture of bacillus subtilis TQK used as a starting strain through adopting a composite mutation technology which repeatedly uses UV (ultraviolet), NTG (nitrosoguanidine) and microwave mutation methods twice. The bacillus subtilis TQB strain has a preservation number of CCTCC (China Center for Type Culture Collection) No.M211147 and can be used for producing high-efficiency beta-mannase and enzyme products BM-I and BM-II. The high-efficiency beta-mannase with average enzyme activity of between 1000 and 2,000mu/ml can be obtained by fermentation under an optimal enzyme production condition, 1ml of enzyme solution can convert 10 to 20g of mannan, and the concentration of a substrate is between 10 and 20 percent. The TQBm strain cultured by the invention has high enzyme production capacity and high enzyme activity; and by using the enzyme product, mannan in konjak, cluster beans, locust beans, sesbania and other plants can be efficiently and economically hydrolyzed to produce mannooligosaccharides.

Description

technical field [0001] The invention relates to microbial fermentation technology and enzyme engineering technology, more specifically, a bacillus for highly expressing β-mannanase and its enzyme product and production method. Background technique [0002] β-mannanase is a kind of endohydrolase that can hydrolyze mannan containing β-glucosidic bond and β-mannosidic bond. Mannan is mainly found in konjac gum, guar gum and locust bean gum , Squat gum, the main components are glucomannan and galactomannan, etc., which constitute the second largest component of plant hemicellulose, and the enzyme product that hydrolyzes mannan in these plants is β-mannan carbohydrase. [0003] Since Akio.T and other American scientists first published the research results of mannanase in the 1980s (Akino T, Nakmura N, Horkoshi K.et al. Characterization of three β-mannanase of an alkalophilic Bacillus sp.[J].Agric Biol Chem. 1988. 52 (3)773-779), the study of mannanase and its enzymatic prepa...

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Problems solved by technology

In some of the above studies, either the enzyme activity is not high, the substrate concentration is low, the cost is high, and the basis for industrial production is lacking (especially for galactomannan); Acid, which brings d