Construction of a temperature-controlled Aspergillus niger gene engineered to express cellulase

Abstract

The invention discloses construction of a temperature-controlled aspergillus niger genetically engineered bacterium started to express an excision enzyme of cellulose and belongs to the field of enzyme engineering. The aspergillus niger genetically engineered bacterium disclosed by the invention is an aspergillus niger strain which is integrated with a gene of the excision enzyme of cellulose in a position of a heat shock protein gene. Construction of the aspergillus niger genetically engineered bacterium comprises the following steps: synthesizing a homologous recombinant fragment shown in a nucleotide sequence such as SEQ ID NO. 1; enzyme-digesting the recombinant fragment and a pWM1 plasmid by using Sa1I and then connecting transformed DH5alpha to obtain a homologous recombinant plasmid; transforming agrobacterium by using the homologous recombinant plasmid and obtaining the target strain by agrobacterium tumefaciens-mediated transformation. According to the invention, heat shock expression of the excision enzyme of cellulose is realized, so that the enzyme constitution of the cellulose of aspergillus niger is reasonable, so that the catalytic capacity of the cellulose is enhanced; the strain constructed does not generate toxins and is high in safety and suitable for industrial application.

Description

technical field [0001] The invention belongs to the field of enzyme engineering, and in particular relates to a genetic engineering bacterium of Aspergillus niger capable of expressing cellulase exocutase through temperature control and a construction method thereof. Background technique [0002] Cellulose is the most abundant renewable resource on the earth. The cellulose produced by photosynthesis on the earth reaches about 10 billion tons every year. The use of cellulose to produce bioenergy is the key to alleviating the energy crisis and realizing the sustainable development of human beings. [0003] The key to cellulose utilization is to degrade cellulose into fermentable sugar-glucose. The degradation of cellulose requires the joint action of exonuclease, endonuclease and glucosidase. Among them, exolytic enzymes degrade the crystal structure of cellulose, which is the rate-limiting step for cellulase to degrade cellulose, while endolytic enzymes degrade long fragment...

AI Technical Summary

Problems solved by technology

Mixing with high exonuclease activity cellulase itself increases the process of mixing and increases the cost of degradation

And the cost of cellulase with high exonuclease activity is also high

Mixed fermentation due to toxins produced by Trichoderma reesei greatly limits the scope of use of cellulase