title: Improvement of acetic acid tolerance of Saccharomyces cerevisiae using a zinc-finger-based artificial transcription factor and identification of novel genes involved in acetic acid tolerance.
abstract: Acetic acid is present in cellulosic hydrolysate as a potent inhibitor, and the superior acetic acid tolerance of Saccharomyces cerevisiae ensures good cell viability and efficient ethanol production when cellulosic raw materials are used as substrates. In this study, a mutant strain of S. cerevisiae ATCC4126 (Sc4126-M01) with improved acetic acid tolerance was obtained through screening strains transformed with an artificial zinc finger protein transcription factor (ZFP-TF) library. Further analysis indicated that improved acetic acid tolerance was associated with improved catalase (CAT) activity. The ZFP coding sequence associated with the improved phenotype was identified, and real-time RT-PCR analysis revealed that three of the possible genes involved in the enhanced acetic acid tolerance regulated by this ZFP-TF, namely YFL040W, QDR3, and IKS1, showed decreased transcription levels in Sc4126-M01 in the presence of acetic acid, compared to those in the control strain. Sc4126-M01 mutants having QDR3 and IKS1 deletion (ΔQDR3 and ΔIKS1) exhibited higher acetic acid tolerance than the wild-type strain under acetic acid treatment. Glucose consumption rate and ethanol productivity in the presence of 5 g/L acetic acid were improved in the ΔQDR3 mutant compared to the wild-type strain. Our studies demonstrated that the synthetic ZFP-TF library can be used to improve acetic acid tolerance of S. cerevisiae and that the employment of an artificial transcription factor can facilitate the exploration of novel functional genes involved in stress tolerance of S. cerevisiae.
authors.affiliation: School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China.
authors.forename: Cui
authors.initials: C
authors.lastname: Ma
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Wei
authors.forename: Cuihuan
authors.initials: C
authors.lastname: Sun
authors.forename: Fei
authors.initials: F
authors.lastname: Zhang
authors.forename: Jianren
authors.initials: J
authors.lastname: Xu
authors.forename: Xinqing
authors.initials: X
authors.lastname: Zhao
authors.forename: Fengwu
authors.initials: F
authors.lastname: Bai
mesh_terms: D019342:Acetic Acid / Q000378:metabolism* / Q000633:toxicity*; D002374:Catalase / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004361:Drug Tolerance; D000431:Ethanol / Q000378:metabolism; D017353:Gene Deletion; D020869:Gene Expression Profiling; D005947:Glucose / Q000378:metabolism; D060847:Metabolic Engineering; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*
chemical_list: D004271:DNA, Fungal; D011994:Recombinant Proteins; D014157:Transcription Factors; D000431:Ethanol; D002482:Cellulose; D002374:Catalase; D005947:Glucose; D019342:Acetic Acid