基于基因组DNA诱变的遗传重组改造乙醇工业酵母的耐热性及发酵性能

Improvement of thermal adaptability and fermentation of industrial ethanologenic yeast by genomic DNA mutagenesis-based genetic recombination

摘要:

酵母菌是乙醇发酵工业中非常重要的微生物细胞工厂，发酵过程中温度变化胁迫一直是影响生产效率的重要瓶颈之一，选育具有广泛温度适应性的酵母菌株对提高发酵性能和降低生产成本具有重要意义。通过化学诱变和基于基因组DNA诱变的遗传重组技术对乙醇工业酵母菌的温度适应性进行改造，获得耐热性能和发酵性能得到提高的重组酿酒酵母Saccharomyces cerevisiae T44-2。重组菌株T44-2的最高生长温度比原始菌株CE6提高了3 ℃，48 ℃和52 ℃热激处理1 h，重组菌株的细胞存活率分别是原始菌株的1.84

Abstract:

Ethanol is an attractive alternative to fossil fuels. Saccharomyces cerevisiae is the most important ethanol producer. However, in the process of industrial production of ethanol, both cell growth and fermentation of ethanologenic S. cerevisiae are dramatically affected by environmental stresses, such as thermal stress. In this study, we improved both the thermotolerance and fermentation performance of industrial ethanologenic S. cerevisiae by combined usage of chemical mutagenesis and genomic DNA mutagenesis-based genetic recombination method. The recombinant S. cerevisiae strain T44-2 could grow at 44 °C, 3 °C higher than that of the original strain CE6. The survival rate of T44-2 was 1.84 and 1.87-fold of that of CE6 when heat shock at 48 °C and 52 °C for 1 h respectively. At temperature higher than 37 °C, recombinant strain T44-2 always gave higher cell growth and ethanol production than those of strain CE6. Meanwhile, from 30 °C to 40 °C, recombinant strain T44-2 produces 91.2–83.8 g/L of ethanol from 200 g/L of glucose, which indicated that the recombinant strain T44-2 had both thermotolerance and broad thermal adaptability. The work offers a novel method, called genomic DNA mutagenesis-based genetic recombination, to improve the physiological functions of S. cerevisiae.