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Evaluation of the competitivity of Saccharomyces cerevisiae native yeasts isolated from the alcoholic fermentation

Grant number: 13/18845-7
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): December 01, 2013
Effective date (End): November 30, 2014
Field of knowledge:Biological Sciences - Microbiology
Principal Investigator:Sandra Regina Ceccato Antonini
Grantee:Isis Gabriela Barbosa Carvalho
Home Institution: Centro de Ciências Agrárias (CCA). Universidade Federal de São Carlos (UFSCAR). Araras , SP, Brazil

Abstract

In the fermentation environment, it is very common to isolate Saccharomyces cerevisiae yeasts with a different phenotype in relation to the selected strain, which commonly display smooth colony and dispersed cells. Strains with rough colony phenotype and cells in pseudohyphae, slow fermenters, are difficult to manage when they are present in the fermentation tanks. The search for characteristics/features that allow the control of only one phenotype preserving the other is very complicated. A previous work of our research group showed a relative differential sensitivity to stressing factors like low pH and high ethanol concentration, when both colony phenotypes of S. cerevisiae were compared (Reis, 2011). This research line is being explored in our lab in another research project supported by Fapesp (process 2012/18082-0, PhD fellowship to Vanda Renata Reis). Considering that the competition is determined mainly by the ability to utilize the limiting growth factor and this is still an unknown point regarding the rough colonies, this work aims to verify the competitive capacity of rough S. cerevisiae strains in conditions of low sugar concentration, different nitrogen sources and in the presence of sulphite, present in molasses. The results will be compared to the performance of the strain PE-2 of S. cerevisiae (smooth colony with dispersed cells), extensively utilized industrially, in the same conditions.