title: Quantitative proteomic analysis of the Saccharomyces cerevisiae industrial strains CAT-1 and PE-2.
abstract: Brazilian ethanol fermentation process commonly uses baker's yeast as inoculum. In recent years, wild type yeast strains have been widely adopted. The two more successful examples are PE-2 and CAT-1, currently employed in Brazilian distilleries. In the present study, we analyzed how these strains compete for nutrients in the same environment and compared the potential characteristics which affect their performance by applying quantitative proteomics methods. Through the use of isobaric tagging, it was possible to compare protein abundances between both strains during the fermentation process. Our results revealed a better fermentation performance and robustness of CAT-1 strain. The proteomic results demonstrated many possible features that may be linked to the improved fermentation traits of the CAT-1. Proteins involved in response to oxidative stress (Sod1 and Trx1) and trehalose synthesis (Tps3) were more abundant in CAT-1 than in PE-2 after a fermentation batch. Tolerance to oxidative stress and trehalose accumulation were subsequently demonstrated to be enhanced for CAT-1, corroborating the comparative proteomic results. The importance of trehalose and the antioxidant system was confirmed by using mutant stains deleted in Sod1, Trx1 or Tps3. These deletions impaired fermentation performance, strengthening the idea that the abilities of accumulating high levels of trehalose and coping with oxidative stress are crucial for improving fermentation.
  
  
  
  The importance of the present works emerges from the necessity to better understand the peculiar biological features from two important bioethanol industrial strains of Saccharomyces cerevisiae during batch fermentation. We applied an iTRAQ-based quantitative proteomics analysis to compare these two important strains during batch fermentation and identified possible features involved in the fermentation performance. The results provided by this work will serve as an initial framework for future investigations on the biology of both strains.
authors: Laboratory of Investigation of Stress Factors, Department of Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-909, Brazil.
authors: Renata M
authors: RM
authors: Santos
authors: Proteomics Unit, Rio de Janeiro Proteomics Network, Department of Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-909, Brazil.
authors: Fabio C S
authors: FC
authors: Nogueira
authors: Laboratory of Investigation of Stress Factors, Department of Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-909, Brazil.
authors: Aline A
authors: AA
authors: Brasil
authors: Computational Mass Spectrometry Group, Carlos Chagas Institute, Fiocruz Paraná 81350-010, Brazil.
authors: Paulo C
authors: PC
authors: Carvalho
authors: Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA.
authors: Felipe V
authors: FV
authors: Leprevost
authors: Proteomics Unit, Rio de Janeiro Proteomics Network, Department of Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-909, Brazil.
authors: Gilberto B
authors: GB
authors: Domont
authors: Laboratory of Investigation of Stress Factors, Department of Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro 21941-909, Brazil.
authors: Elis C A
authors: EC
authors: Eleutherio
mesh_terms: D001938:Brazil; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D018384:Oxidative Stress; D040901:Proteomics / Q000379:methods; D012441:Saccharomyces cerevisiae / Q000737:chemistry; D029701:Saccharomyces cerevisiae Proteins / Q000032:analysis*; D014199:Trehalose
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D000431:Ethanol; D014199:Trehalose
keywords: Alcoholic fermentation; Quantitative proteomics; Saccharomyces cerevisiae; iTRAQ