Industrial saccharomyces cerevisiae strain for synchronously producing xylitol and ethanol and construction method of industrial saccharomyces cerevisiae strain

Abstract

The invention provides an industrial saccharomyces cerevisiae strain for synchronously producing xylitol and ethanol and a construction method of the industrial saccharomyces cerevisiae strain. The strain highly expresses an FPS1 gene and an XYL1 gene. Specifically, the strain is SEB20, the classification name of the strain is Saccharomyces cerevisiae, and the preservation number of the strain is CGMCC No.22590. The strain is obtained by taking the Saccharomyces cerevisiae SEB10 as an original strain, replacing a promoter PFPS1 of a gene FPS1 with a strong promoter PTDH3, and increasing the copy number of a CtXYL1 gene while knocking out two site gene coding regions of SOR1 and SOR2. Under the condition that the initial glucose concentration of the saccharomyces cerevisiae strain SEB20 is relatively high, the xylose consumption rate and the yield of xylitol and ethanol are improved. Under a test tube fermentation condition, compared with SEB10, the xylose consumption rate is increased by 73.5%, and the xylitol yield is increased by 27.0%. Under the conditions of straw pre-saccharification and simultaneous saccharification fermentation, compared with an original strain SEB10, the strain SEB20 has the advantages that the xylose consumption rate is increased by 24.1%, the xylitol yield is increased by 42.9%, the xylitol yield is close to a theoretical value 1.0, and the ethanol yield is increased by 5.0%.

Description

technical field [0001] The invention relates to the technical field of microbial genetic engineering, in particular to an industrial Saccharomyces cerevisiae strain synchronously producing xylitol and ethanol and a construction method thereof. Background technique [0002] The massive consumption of fossil fuels has caused serious problems such as energy depletion, rising prices and global climate change. Lignocellulosic biomass such as agricultural waste (bagasse, corncobs, corn stalks, wheat and rice straw, etc.), waste wood, and industrial waste (including pulp, paper processing waste, etc.) can be used as potential raw materials for biofuels. It is widely sourced, low-cost, and undergoes environmentally sound biological treatment to produce fuel ethanol, which benefits rural communities and society as a whole with macroeconomic benefits. In China, more than 900 million tons of straw are produced every year, and the comprehensive utilization rate of straw exceeds 85%. Af...

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Problems solved by technology

[0005] The object of the present invention is to solve the problem that after the existing CtXYL1 (encoding xylose reductase) gene derived from Candida tropicalis is expressed heterologously in Saccharomyces cerevisiae, in order to simulate its fermentation process in lignocellulose hydrolyzate, select a high initial concentration When glucose is supplied as a carbon source, the recombinant bacteria constructed by the xylose metabolism rate is slow, the xylitol yield is low, and cannot meet the needs of fermentation, and then a high-expression FPS1 gene is provided to solve the above problems, and the SOR1 / SOR2 The industrial Saccharomyces cerevisiae strain SEB20 with high xylitol and ethanol production under co-fermentation glucose and xylose conditions by replacing the gene coding region with CtXYL1 gene and its construction method

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