液泡蛋白酶B对酿酒酵母高温乙醇发酵效率的影响

【目的】提高酿酒酵母的高耐温性，从而提高菌株在高温下的乙醇发酵性能。【方法】利用染色体整合过表达酿酒酵母液泡蛋白酶B编码基因PRB1。【结果】在41 °C高温条件下进行乙醇发酵，过表达PRB1基因的重组酿酒酵母菌株可在31 h内消耗全部的葡萄糖，而对照菌株在相同时间内仅消耗不到一半的葡萄糖。【结论】利用蛋白酶B基因过表达可构建耐高温酿酒酵母菌株，提高在高温条件下乙醇的发酵效率。

Effect of vacuolar proteinase B on high temperature ethanol fermentation of Saccharomyces cerevisiae

Objective] To improve thermal tolerance of Saccharomyces cerevisiae strains for efficient ethanol fermentation under high temperature. Methods] Vacuolar proteinase B encoding gene PRB1 was integrated into the genome of S. cerevisiae, and cell growth and ethanol fermentation of the recombinant strain were compared with those of the control strain carrying the empty plasmid at 41 °C. Results] PRB1 overexpressing strain consumed glucose completely in the fermentation broth within 31 h, whereas high residual glucose was detected in the fermentation broth of the control strain (35 g/L, about 40% of the total sugar amount) at 23 h and the glucose level was not changed until 31 h. Conclusion] Overexpression of vacuolar protease B encoding gene improved yeast thermal tolerance and ethanol production under high temperature. The robust strain developed in this study has provided basis to further improve thermal tolerance and efficiency of high-temperature ethanol fermentation of the industrial strains and reduce the production cost of fuel ethanol.