title: Improvement of oxidative stress tolerance in Saccharomyces cerevisiae through global transcription machinery engineering.
abstract: Excessive oxidative stress poses significant damage to yeast cells during fermentation process, and finally affects fermentation efficiency and the quality of products. In this paper, global transcription machinery engineering was employed to elicit Saccharomyces cerevisiae phenotypes of higher tolerance against oxidative stress caused by H2O2. Two strains from two plasmid-based mutagenesis libraries (Spt15 and Taf25), which exhibited significant increases in oxidative stress tolerance, were successfully isolated. At moderate H2O2 shock (≤3.5 mM), a positive correlation was found between the outperformance in cell growth of the oxidation-tolerate strains and H2O2 concentration. Several mutations were observed in the native transcription factors, which resulted in a different transcriptional profile compared with the control. Catalase and superoxide dismutase activities of the two mutants increased under H2O2 stress conditions. Fermentation experiments revealed that the mutant strain taf25-3 has a shorter lag phase compared to the control one, indicating that taf25-3 had improved adaptation ability to H2O2-induced oxidative stress and higher fermentation efficiency. Our study demonstrated that several amino acid substitutions in general transcription factors (Spt15 and Taf25) could modify the cellular oxidation defense systems and improve the anti-oxidation ability of S. cerevisiae. It could make the industrial ethanol fermentation more efficient and cost-effective by using the strain of higher stress tolerance.
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Tsinghua East Road, Haidian District, PO Box 398, Beijing, 100083, China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Zhao
authors.forename: Jingyuan
authors.initials: J
authors.lastname: Li
authors.forename: Beizhong
authors.initials: B
authors.lastname: Han
authors.forename: Xuan
authors.initials: X
authors.lastname: Li
authors.forename: Jingyu
authors.initials: J
authors.lastname: Chen
mesh_terms: D019943:Amino Acid Substitution; D060846:Cell Engineering; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D016296:Mutagenesis; D018384:Oxidative Stress / Q000235:genetics*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D035381:TATA-Binding Protein Associated Factors / Q000235:genetics*; D035181:TATA-Box Binding Protein / Q000235:genetics*; D035362:Transcription Factor TFIID / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D017382:Reactive Oxygen Species; C115017:SPT15 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C100497:TAF10 protein, S cerevisiae; D035381:TATA-Binding Protein Associated Factors; D035181:TATA-Box Binding Protein; D035362:Transcription Factor TFIID; D000431:Ethanol