DEVELOPMENT OF BIOPROSPECTING TOOLS FOR OENOLOGICAL APPLICATIONS
Wine production is a complex biochemical process that involves a heterogeneous microbiota consisting of different microorganisms such as yeasts, bacteria, and filamentous fungi. Among these microorganisms, yeasts play a predominant role in the chemistry of wine, as they actively participate in alcoho-lic fermentation, a biochemical process that transforms the sugars in grapes into ethanol and carbon dioxide while producing additional by-products. The quality of the final product is greatly influenced by the microbiota present in the grape berry, and the demand for indigenous yeast starters adapted to specific grape must and reflecting the biodiversity of a particular region is increasing. This supports the concept that indigenous yeast strains can be associated with a “terroir”.
While some non-Saccharomyces species have been found to affect the chemical composition of wine, their low fermentation ability limits their usefulness, as they are unable to fully metabolize the sugars in the grape juice and produce only small amounts of ethanol. However, non-Saccharomyces strains have several oenological properties that are fundamental for the organoleptic properties of wine. As a result, the use of mixed non-Saccharomyces/Saccharomyces fermentation can be a valid alternative to spontaneous fermentation, as it can mimic natural biodiversity and increase the organoleptic properties of wine while minimizing microbial alterations.
The objectives of this work were to prospect and precisely identify genetically yeasts (more than 300 strains) of interest for the production of fermented beverages using an innovative protocol in several Swiss vineyards, establish a methodology to phenotypically characterize the isolated yeasts, and develop a procedure to assist winegrowers in their use of mixed saccharomyces and non-saccharomyces yeasts.
Issue: OENO Macrowine 2023
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yeast, bioprospection, wine