title: Expression of Mitochondrial Cytochrome C Oxidase Chaperone Gene (COX20) Improves Tolerance to Weak Acid and Oxidative Stress during Yeast Fermentation.
abstract: BACKGROUND
  Saccharomyces cerevisiae is the micro-organism of choice for the conversion of fermentable sugars released by the pre-treatment of lignocellulosic material into bioethanol. Pre-treatment of lignocellulosic material releases acetic acid and previous work identified a cytochrome oxidase chaperone gene (COX20) which was significantly up-regulated in yeast cells in the presence of acetic acid.
  
  
  RESULTS
  A Δcox20 strain was sensitive to the presence of acetic acid compared with the background strain. Overexpressing COX20 using a tetracycline-regulatable expression vector system in a Δcox20 strain, resulted in tolerance to the presence of acetic acid and tolerance could be ablated with addition of tetracycline. Assays also revealed that overexpression improved tolerance to the presence of hydrogen peroxide-induced oxidative stress.
  
  
  CONCLUSIONS
  This is a study which has utilised tetracycline-regulated protein expression in a fermentation system, which was characterised by improved (or enhanced) tolerance to acetic acid and oxidative stress.
authors.affiliation: University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom.
authors.forename: Vinod
authors.initials: V
authors.lastname: Kumar
authors.affiliation: University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Hart
authors.affiliation: University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom.
authors.forename: Ethiraju R
authors.initials: ER
authors.lastname: Keerthiraju
authors.affiliation: University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Waldron
authors.affiliation: University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Tucker
authors.affiliation: University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom.
authors.forename: Darren
authors.initials: D
authors.lastname: Greetham
mesh_terms: D019342:Acetic Acid / Q000494:pharmacology*; D005285:Fermentation / Q000187:drug effects / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006868:Hydrolysis; D008565:Membrane Proteins / Q000235:genetics*; D024101:Mitochondrial Proteins / Q000235:genetics*; D018384:Oxidative Stress / Q000187:drug effects; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D013752:Tetracycline / Q000494:pharmacology; D014908:Triticum / Q000378:metabolism
chemical_list: C405324:Cox20 protein, S cerevisiae; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins; D006861:Hydrogen Peroxide; D013752:Tetracycline; D019342:Acetic Acid