Industrial Saccharomyces cerevisiae strain for high-yield production of xylitol and ethanol by co-fermenting xylose and glucose and construction method

Abstract

The invention discloses an industrial Saccharomyces cerevisiae strain for high-yield production of xylitol and ethanol by co-fermenting xylose and glucose. The industrial Saccharomyces cerevisiae strain is SEB10 with a preservation number of CGMCC NO. 14777. The invention further relates to a construction method of the Saccharomyces cerevisiae strain, and the method comprises the following steps:selecting an original strain; using a Cre-LoxP system to knock out a KanMX gene of the original strain and construct an SEB6kan strain; mutating an HXT3 gene of the SEB6kan strain by using a CRISPR / Cas9 system to construct an SEB6kan-M-HXT3 strain. Through a CRISPR / CasS9 gene editing technology, the 367th site of a transport protein HXT3 can be rapidly and accurately mutated from asparagine to alanine at a fixed point; under the condition with high initial glucose concentration, the Saccharomyces cerevisiae strain prepared according to the construction method provided by the invention improvesthe xylose transport rate, thereby improving the capability of Saccharomyces cerevisiae to co-ferment xylose and glucose and improving the performance of the Saccharomyces cerevisiae to produce xylitol and ethanol; under the condition with a fermentation tank, the xylose consumption rate is increased by 12%, the xylitol production is increased by 13%, the ethanol production is increased by 22%, and the xylitol yield is close to a theoretical value of 1.0.

Description

technical field [0001] The invention relates to the technical field of microbial genetic engineering, in particular to an industrial Saccharomyces cerevisiae strain that utilizes the CRISPR / Cas9 system to mutate the HXT3 gene to improve the xylose transport rate and co-ferment xylose and glucose to high-yield xylitol and ethanol and its construction method. Background technique [0002] Lignocellulosic biomass is mainly derived from agricultural waste, and agricultural waste such as straw is the most abundant renewable organic matter on the earth. About 900 million tons of straw are produced in China every year, and the conversion and treatment methods are still mostly waste or waste. Direct field incineration, the high cost of treatment will cause a great waste of resources, pollute the atmospheric environment, and destroy the ecological balance. The use of biomass resources to produce bioenergy products does not lead to a net increase in the total amount of greenhouse gase...

AI Technical Summary

Problems solved by technology

[0009] The industrial Saccharomyces cerevisiae expression system is relatively complicated. The CtXYL1 (encoding xylose reductase) gene from Candida tropicalis is currently expressed heterologously in Saccharomyces cerevisiae, in order to simulate its fermentation process in lignocellulose hydrolyzate, select When glucose with a high initial concentration is supplied as a carbon source, the recombinant bacteria constructed by it have slow xylose metabolism and low xylitol production, which cannot meet the needs of fermentation

Images