Dekkera and Brettanomyces: characterization and fermentative behavior of strains contaminating alcoholic fermentation

• Grant number: 05/04011-0
• Support Opportunities: Regular Research Grants
• Start date: June 01, 2006
• End date: August 31, 2009
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Sandra Regina Ceccato Antonini
• Grantee: Sandra Regina Ceccato Antonini
• Host Institution: Centro de Ciências Agrárias (CCA). Universidade Federal de São Carlos (UFSCAR). Araras , SP, Brazil

Abstract

Brettanomyces/Dekkera yeasts are involved in the process of deterioration of wines after the end of alcoholic and malolactic fermentations and are responsible for the formation of secondary compounds that confer unpleasant odors on the wines. This is down to an opportunistic and non-competitive microorganism which has already been documented in the continuous process of ethanol production and which can be combated with the use of killer yeast. Owing to the important role these yeasts play as contaminants in the fermentative process of wine and alcohol and the scant information there is on the subject, especially regarding ethanolic fermentation, the present study proposes to characterize the strains of Dekkera/Brettanomyces isolates from a variety of fermentative processes using physiological/biochemical tests, to verify the killer activity and the sensitivity of the same yeasts to a variety of killer toxins, in addition to evaluating the growth and the fermentative behavior of these strains in industrial conditions. It is hoped that the results may contribute to the understanding of the role the Dekkera/Brettanomyces yeasts play in the process of alcoholic fermentation in comparison with isolates of winery environments, where knowledge is better established. Fast and reliable tests are also proposed for the detection of these strains in the processes, even though they have slow rates of growth and a low level of occurrence. (AU)