The Laboratory of Molecular Genetics and Breeding of Yeast, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.
J Ind Microbiol Biotechnol. 2012 Jan;39(1):73-80. doi: 10.1007/s10295-011-1001-0. Epub 2011 Jun 23.
Bioethanol is an attractive alternative to fossil fuels. Saccharomyces cerevisiae is the most important ethanol producer. However, yeast cells are challenged by various environmental stresses during the industrial process of ethanol production. The robustness under heat, acetic acid, and furfural stresses was improved for ethanologenic S. cerevisiae in this work using genome shuffling. Recombinant yeast strain R32 could grow at 45°C, and resist 0.55% (v/v) acetic acid and 0.3% (v/v) furfural at 40°C. When ethanol fermentation was conducted at temperatures ranging from 30 to 42°C, recombinant strain R32 always gave high ethanol production. After 42 h of fermentation at 42°C, 187.6 ± 1.4 g/l glucose was utilized by recombinant strain R32 to produce 81.4 ± 2.7 g/l ethanol, which were respectively 3.4 and 4.1 times those of CE25. After 36 h of fermentation at 40°C with 0.5% (v/v) acetic acid, 194.4 ± 1.2 g/l glucose in the medium was utilized by recombinant strain R32 to produce 84.2 ± 4.6 g/l of ethanol. The extent of glucose utilization and ethanol concentration of recombinant strain R32 were 6.3 and 7.9 times those of strain CE25. The ethanol concentration produced by recombinant strain R32 was 8.9 times that of strain CE25 after fermentation for 48 h under 0.2% (v/v) furfural stress at 40°C. The strong physiological robustness and fitness of yeast strain R32 support its potential application for industrial production of bioethanol from renewable resources such as lignocelluloses.
生物乙醇是一种有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，在乙醇生产的工业过程中，酵母细胞会受到各种环境压力的挑战。本工作采用基因组改组技术，提高了产乙醇酿酒酵母在热、乙酸和糠醛胁迫下的鲁棒性。重组酵母菌株 R32 能够在 45°C 下生长，并在 40°C 下耐受 0.55%（v/v）乙酸和 0.3%（v/v）糠醛。当乙醇发酵在 30 至 42°C 的温度范围内进行时，重组菌株 R32 始终能产生高浓度的乙醇。在 42°C 下发酵 42 h 后，重组菌株 R32 利用 187.6 ± 1.4 g/l 葡萄糖产生 81.4 ± 2.7 g/l 乙醇，分别是对照菌株 CE25 的 3.4 和 4.1 倍。在 40°C、0.5%（v/v）乙酸条件下发酵 36 h 后，重组菌株 R32 利用 194.4 ± 1.2 g/l 葡萄糖产生 84.2 ± 4.6 g/l 乙醇。重组菌株 R32 的葡萄糖利用率和乙醇浓度分别是对照菌株 CE25 的 6.3 和 7.9 倍。在 40°C、0.2%（v/v）糠醛胁迫下发酵 48 h 后，重组菌株 R32 的乙醇浓度是对照菌株 CE25 的 8.9 倍。酵母菌株 R32 具有较强的生理鲁棒性和适应性，支持其在可再生资源（如木质纤维素）生产生物乙醇方面的工业应用。
