title: Tolerance of pentose utilising yeast to hydrogen peroxide-induced oxidative stress.
abstract: BACKGROUND
  Bioethanol fermentations follow traditional beverage fermentations where the yeast is exposed to adverse conditions such as oxidative stress. Lignocellulosic bioethanol fermentations involve the conversion of pentose and hexose sugars into ethanol. Environmental stress conditions such as osmotic stress and ethanol stress may affect the fermentation performance; however, oxidative stress as a consequence of metabolic output can also occur. However, the effect of oxidative stress on yeast with pentose utilising capabilities has yet to be investigated.
  
  
  RESULTS
  Assaying for the effect of hydrogen peroxide-induced oxidative stress on Candida, Pichia and Scheffersomyces spp. has demonstrated that these yeast tolerate hydrogen peroxide-induced oxidative stress in a manner consistent with that demonstrated by Saccharomyces cerevisiae. Pichia guillermondii appears to be more tolerant to hydrogen peroxide-induced oxidative stress when compared to Candida shehatae, Candida succiphila or Scheffersomyces stipitis.
  
  
  CONCLUSIONS
  Sensitivity to hydrogen peroxide-induced oxidative stress increased in the presence of minimal media; however, addition of amino acids and nucleobases was observed to increase tolerance. In particular adenine increased tolerance and methionine reduced tolerance to hydrogen peroxide-induced oxidative stress.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Spencer
authors.forename: Trevor G
authors.initials: TG
authors.lastname: Phister
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Smart
authors.affiliation: School of Biosciences, University of Nottingham, Loughborough, Leics LE12 5RD, UK. Darren.greetham@nottingham.ac.uk.
authors.forename: Darren
authors.initials: D
authors.lastname: Greetham
mesh_terms: D000222:Adaptation, Physiological; D056804:Biofuels; D002175:Candida / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation / Q000187:drug effects; D006601:Hexoses / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D018384:Oxidative Stress; D010429:Pentoses / Q000378:metabolism; D010843:Pichia / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D004718:Saccharomycetales / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D013045:Species Specificity
chemical_list: D056804:Biofuels; D006601:Hexoses; D010429:Pentoses; D000431:Ethanol; D006861:Hydrogen Peroxide