Liu Xiuying, He Xiuping, Lu Ying, Zhang Borun
Laboratory of Yeast Molecular Genetics and Breeding, Institute of Microbiology, Chinese Academy of Sciences, Beijing 1 00101, China
Sheng Wu Gong Cheng Xue Bao. 2011 Jul;27(7):1049-56.
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 degrees C, 3 degrees 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 degrees C and 52 degrees C for 1 h respectively. At temperature higher than 37 degrees C, recombinant strain T44-2 always gave higher cell growth and ethanol production than those of strain CE6. Meanwhile, from 30 degrees C to 40 degrees 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.
乙醇是一种颇具吸引力的化石燃料替代品。酿酒酵母是最重要的乙醇生产菌。然而，在乙醇的工业生产过程中，产乙醇酿酒酵母的细胞生长和发酵都会受到热应激等环境压力的显著影响。在本研究中，我们通过化学诱变和基于基因组DNA诱变的基因重组方法联用，提高了工业产乙醇酿酒酵母的耐热性和发酵性能。重组酿酒酵母菌株T44 - 2能在44℃生长，比原始菌株CE6高3℃。当在48℃和52℃热激1小时时，T44 - 2的存活率分别是CE6的1.84倍和1.87倍。在高于37℃的温度下，重组菌株T44 - 2的细胞生长和乙醇产量始终高于菌株CE6。同时，在30℃至40℃范围内，重组菌株T44 - 2能从200 g/L葡萄糖中产生91.2 - 83.8 g/L乙醇，这表明重组菌株T44 - 2既具有耐热性又具有广泛的热适应性。这项工作提供了一种名为基于基因组DNA诱变的基因重组的新方法，以改善酿酒酵母的生理功能。
