Genome-Scale Screen Of Transcription Factor Genes Affecting The Ethanol Fermentation Of Saccharomyces Cerevisiae

The budding yeast Saccharomyces cerevisiae remains a central position among biofuel-producing organisms.However,the gene expression regulatory networks behind the ethanol fermentation is still not fully understood.Using a static fermentation model,we have examined the ethanol yields on biomass of deletion mutants for all yeast nonessential genes encoding transcription factors and their related proteins in the yeast genome.A total of 18(about 10%)transcription factors are identified to be regulators of ethanol production during fermentation.These transcription factors are mainly involved in cell cycling,chromatin remodeling,transcription,stress response,protein synthesis and lipid synthesis.Compared to the wild type,five single-gene deletion mutants for MBP1,UME6,SWI4,SPT1 and SWI6 showed increased ethanol production at 32 h and 52 h post-inoculation,but five single-gene deletion mutants for SRB8,NGG1,RTF1,RSC1 and SWI3 showed increased ethanol production only at 52 h post-inoculation.Contrarily,eight single-gene deletion mutants for SEF1,INO2,INO4,RIC1,SPS18,YNR063 W,HAC1 and HAT1 exhibited reduced ethanol production at 32 h and 52 h post-inoculation,Among these 10 deletion mutants showing increased ethanol production,only the deletion mutant for RSC1 showed ethanol tolerance,but other nine mutants did not.These data provide a basis for further understanding mechanisms regulating ethanol production in budding yeast.At the end,we tested the ability of these mutants in ethanol production using a 5 L batch fermenter.Two deletion mutants for ACE2 and HAT1 showed increased ethanol production in industrial fermentation medium.However,deletion of ACE2 did not increase ethanol production in two industrial S.cerevisiae strains,Anqi and Fali.