Abstract:For the yeast Saccharomyces cerevisiae, the cAMP signal transduction pathway plays an important role in the control of metabolism, proliferation, differentiation and acquisition of stress resistance. During the fermentation process, stress environments such as high temperature, high osmotic pressure, nutrient starvation, high alcohol toxicity, etc. are unavoidable. There is a high requirement for yeast tolerance in industrial applications. It can increase the fermentation performance of strains and reduce the energy consumption during fermentation. The constructed mutant has great signification in industrial application. Based on the existing strain AY12a in the laboratory, the strong promoter PGK1p was added to the N-terminus of MSN2 gene to achieve overexpression of the gene by using the intracellular recombination method, using URA3 gene as the screening marker. The mutant AY12a-msn2 was successfully constructed by PCR verification. The results showed that the mutant had no temperature tolerance. The mutant and AY12a were tested for very high gravity (VHG) fermentation, and the alcohol content, residual sugar, 48 h cell survival rate, CO2 weight loss and fermentation time were determined. The results showed that the alcohol content decrease, the residual sugar content and the survival rate of 48 h cells increased. The mutant had longer fermentation time.
