title: Enhanced fermentative performance under stresses of multiple lignocellulose-derived inhibitors by overexpression of a typical 2-Cys peroxiredoxin fromKluyveromyces marxianus.
abstract: BACKGROUND
  Bioethanol from lignocellulosic materials is of great significance to the production of renewable fuels due to its wide sources. However, multiple inhibitors generated from pretreatments represent great challenges for its industrial-scale fermentation. Despite the complex toxicity mechanisms, lignocellulose-derived inhibitors have been reported to be related to the levels of intracellular reactive oxygen species (ROS), which makes oxidoreductase a potential target for the enhancement of the tolerance of yeasts to these inhibitors.
  
  
  RESULTS
  A typical 2-Cys peroxiredoxin fromKluyveromyces marxianusY179 (KmTPX1) was identified, and its overexpression was achieved inSaccharomyces cerevisiae280. Strain TPX1 with overexpressedKmTPX1gene showed an enhanced tolerance to oxidative stresses. Serial dilution assay indicated thatKmTPX1gene contributed to a better cellular growth behavior, when the cells were exposed to multiple lignocellulose-derived inhibitors, such as formic acid, acetic acid, furfural, ethanol, and salt. In particular,KmTPX1expression also possessed enhanced tolerance to a mixture of formic acid, acetic acid, and furfural (FAF) with a shorter lag period. The maximum glucose consumption rate and ethanol generation rate inKmTPX1-expressing strain were significantly improved, compared with the control. The mechanism of improved tolerance to FAF depends on the lower level of intracellular ROS for cell survival under stress.
  
  
  CONCLUSIONS
  A new functional geneKmTPX1fromK. marxianusis firstly associated with the enhanced tolerance to multiple lignocellulose-derived inhibitors inS. cerevisiae. We provided a possible detoxification mechanism of theKmTPX1for further theoretical research; meanwhile, we provided a powerful potential for application of theKmTPX1overexpressing strain in ethanol production from lignocellulosic materials.
authors.affiliation: School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024 China.
authors.forename: Jiaoqi
authors.initials: J
authors.lastname: Gao
authors.affiliation: School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024 China.
authors.forename: Hualiang
authors.initials: H
authors.lastname: Feng
authors.affiliation: School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024 China.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Yuan
authors.affiliation: School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024 China.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024 China.
authors.forename: Shengbo
authors.initials: S
authors.lastname: Hou
authors.affiliation: School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024 China.
authors.forename: Shijun
authors.initials: S
authors.lastname: Zhong
authors.affiliation: School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024 China.|State Key Laboratory of Microbial Metabolism, Shanghai Jiaotong University, Shanghai, 200240 China.
authors.forename: Fengwu
authors.initials: F
authors.lastname: Bai
keywords: Ethanol fermentation; Inhibitors; Kluyveromyces marxianus; Lignocellulose; Peroxiredoxin; Tolerance