BELY Marina
Associate professor in microbiology, I am working at the Institute of Vine and Wine Sciences of the University of Bordeaux. My work involves control of alcoholic fermentation and yeast selection. My current area of research is the investigation of non-Saccharomyces yeasts with a specific focus on yeast of interest in enology such as Torulaspora delbrueckii.
Grape must is a complex ecosystem in which numerous microbial interactions occur. In the early stages of winemaking, non-Saccharomyces yeasts are predominant. Due to the low ethanol tolerance of these yeasts and microbial competition, Saccharomyces cerevisiae becomes quickly predominant and the main agent of alcoholic fermentation. In this conference, first a short presentation about the main species involved in the alcoholic fermentation, Saccharomyces cerevisiae, will be provided (taxonomy, morphology, reproduction and metabolisms). Then the diversity of yeasts (non-Saccharomyces yeasts and S.cerevisiae) on grapes as well as during the alcoholic fermentation process will be presented. Finally, the various environmental factors acting on the progress of the alcoholic fermentation on which the oenologist can act will be investigated (selected yeast, nitrogen supplementation, temperature, oxygen, must clarification…), classic and hyperosmotic (sauternes) conditions.