Improvement of robustness and ethanol production of ethanologenic Saccharomyces cerevisiae under co-stress of heat and inhibitors

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 45A degrees C, and resist 0.55% (v/v) acetic acid and 0.3% (v/v) furfural at 40A degrees C. When ethanol fermentation was conducted at temperatures ranging from 30 to 42A degrees C, recombinant strain R32 always gave high ethanol production. After 42 h of fermentation at 42A degrees C, 187.6 +/- A 1.4 g/l glucose was utilized by recombinant strain R32 to produce 81.4 +/- A 2.7 g/l ethanol, which were respectively 3.4 and 4.1 times those of CE25. After 36 h of fermentation at 40A degrees C with 0.5% (v/v) acetic acid, 194.4 +/- A 1.2 g/l glucose in the medium was utilized by recombinant strain R32 to produce 84.2 +/- A 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 40A degrees 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.