Abstract
There is a growing interest in understanding and describing natural microbial communities involved in the fermentation of food products such as wine. Numerous studies have analyzed the diversity and dynamics of the different yeasts present during wine alcoholic fermentation. Initially, grape must is generally rich in yeasts belonging to the Hanseniaspora, Metschnikowia, Pichia or Torulaspora genera that are referred to as non-Saccharomyces. These non-Saccharomyces are gradually taken over by Saccharomyces cerevisiae, which dominates the active phase of fermentation. The diversity of yeasts present and environmental variations make it complex to study the interaction mechanisms governing microbial dynamics during fermentation. The aim of this work was therefore to develop a model consortium including several yeast species representative of the diversity found during winemaking. The use of a synthetic community simplifies the study of microbial community dynamics during fermentation by reducing the number of species and using controlled environmental conditions. Based on a literature review, we constructed a model consortium consisting of six species, each labelled with a unique combination of fluorochromes. This enabled us to monitor their proportion in a complex mixture using flow cytometry. We studied pairwise interactions in pairs and consortia of these species, in particular to test a possible link between initial α diversity and fermentation performance under osmotic stress. More generally, this microbiological tool could be useful for understanding a wide range of microbial ecology issues in enological fermentation.