[beta]-mannase heat-resistant mutant M14, recombinant bacterium and application thereof

Abstract

The invention relates to a [beta]-mannase heat-resistant mutant M14, a recombinant bacterium and application of the [beta]-mannase heat-resistant mutant M14 and the recombinant bacterium, and belongs to the field of gene engineering and enzyme engineering. The [beta]-mannase heat-resistant mutant M14 is obtained by adopting a protein surface charge optimization strategy, rationally designing and screening a mutation site, improving [beta]-mannase ManAK from aspergillus candidus, then selecting forward mutation through adoption of a high-throughput screening method, and finally, obtaining 23 [beta]-mannase mutants with improved thermal stability. The heat resistance of the obtained [beta]-mannase mutant is 1.2-3.5 times that of an original gene, the heat resistance is remarkably improved, commercial application of the [beta]-mannase mutant is facilitated, and therefore the production cost is reduced.

Description

technical field

[0001] The invention belongs to the fields of genetic engineering and enzyme engineering, and specifically relates to a kind of beta-mannanase heat-resistant mutants, recombinant bacteria and applications thereof. Background technique

[0002] Mannan is the second largest component of hemicellulose, composed of mannopyranose linked by β-1,4 glycosidic bonds. The complete degradation of mannan requires the synergistic action of mannanase, mannosidase, glucosidase, galactosidase and deacetylase. Among them, mannanase is the key enzyme in the degradation process.

[0003] β-mannanase (EC 3.2.1.78) is capable of hydrolyzing mannan into mannose and mannooligosaccharides by catalyzing β-1,4 mannosidic linkages. As an important industrial enzyme preparation, the enzyme is widely used in renewable energy fields such as animal feed, food processing, medicine, textile, biological bleaching and petroleum. Some of these application fields, especially feed pelleting, r...

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