Effect of Hog1p-CD domain knockout on tolerance of complex inhibitors of Saccharomyces cerevisiae

Abstract

Abstract, the aim of this study was to improve the co-fermentation ability of Saccharomyces cerevisiae and its tolerance to inhibitors, so as to enhance the efficiency of producing second-generation fuel ethanol from Saccharomyces cerevisiae. It was found that there was an antagonism between the robustness of inhibition in hydrolysate and xylose metabolism of Saccharomyces cerevisiae using glucose/xylose. In this study, the 6M-15 yeast strain that has alleviated the robust antagonism of xylose-use and xylose-use was selected in the laboratory. The HOG1 knockout strains 6M-15-HOG1Δ(303-316)Ww and 6M-15-HOG1Δ(303-316) ww were constructed. The relationship between HOG1 gene and the robustness of yeast strains and the antagonism between xylose metabolic efficiency and robustness were discussed. Through a series of experiments, including strain construction, growth curve measurement, tolerance evaluation and xylose metabolizing ethanol production ability test, the results showed that the yeast strains with HOG1 gene knocked out had improved the tolerance of complex inhibitors, but decreased the xylose metabolizing ethanol production ability. In addition, a synergy index (SI) was established to characterize the degree of balance between xylose metabolizing ability to produce ethanol and robustness of the strains. The results showed that 6M-15-HOG1Δ(303-316)Ww strain had the highest degree of antagonistic balance between xylose-producing capacity and acetic acid tolerance, indicating that the strain had good application potential in the actual production process. This study not only provides a molecular mechanism for understanding the physiological response of Saccharomyces cerevisiae in the face of environmental stress, but also provides an experimental basis for improving the production performance of yeast strains by means of genetic engineering, which is of great significance for promoting the industrialization of biomass energy.