title: Increased ethanol production from glycerol by Saccharomyces cerevisiae strains with enhanced stress tolerance from the overexpression of SAGA complex components.
abstract: During the industrial production of ethanol using yeast, the cells are exposed to stresses that affect their growth and productivity; therefore, stress-tolerant yeast strains are highly desirable. To increase ethanol production from glycerol, a greater tolerance to osmotic and ethanol stress was engineered in yeast strains that were impaired in endogenous glycerol production by the overexpression of both SPT3 and SPT15, components of the SAGA (Spt-Ada-Gcn5-acetyltransferase) complex. The engineered strain YPH499fps1Δgpd2Δ (pGcyaDak, pGupSpt3.15Cas) formed significantly more biomass compared to the strain YPH499fps1Δgpd2Δ (pGcyaDak, pGupCas), and both engineered strains displayed increased biomass when compared to the control YPH499 fps1Δgpd2Δ (pESC-TRP) strain. The trehalose accumulation and ergosterol content of these strains were 2.3-fold and 1.6-fold higher, respectively, than the parent strains, suggesting that levels of cellular membrane components were correlated with the enhanced stress tolerance of the engineered strains. Consequently, the ethanol production of the engineered strain YPH499fps1Δgpd2Δ (pGcyaDak, pGupSpt3.15Cas) was 1.8-fold more than that of strain YPH499fps1Δgpd2Δ (pGcyaDak, pGupCas), with about 8.1g/L ethanol produced. In conclusion, we successfully established that the co-expression of SPT3 and SPT15 that improved the fermentation performance of the engineered yeast strains which produced higher ethanol yields than stress-sensitive yeast strains.
authors.affiliation: School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Kyung Ok
authors.initials: KO
authors.lastname: Yu
authors.forename: Ju
authors.initials: J
authors.lastname: Jung
authors.forename: Ahmad Bazli
authors.initials: AB
authors.lastname: Ramzi
authors.forename: Se Hoon
authors.initials: SH
authors.lastname: Choe
authors.forename: Seung Wook
authors.initials: SW
authors.lastname: Kim
authors.forename: Chulhwan
authors.initials: C
authors.lastname: Park
authors.forename: Sung Ok
authors.initials: SO
authors.lastname: Han
mesh_terms: D001709:Biotechnology / Q000379:methods*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D015966:Gene Expression Regulation, Fungal; D005818:Genetic Engineering / Q000379:methods; D005990:Glycerol / Q000378:metabolism*; D018869:Heat-Shock Response / Q000502:physiology; D009997:Osmotic Pressure; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D035181:TATA-Box Binding Protein / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: C115017:SPT15 protein, S cerevisiae; C075582:SPT3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035181:TATA-Box Binding Protein; D014157:Transcription Factors; D000431:Ethanol; D005990:Glycerol