Development of a model consortia of wine yeasts to explore the impact of diversity on wine fermentation.
Résumé
Currently, there is a growing interest in describing and understanding natural microbial community involved in fermented food and beverages such as wine. Hence a lot of studies on wine investigated the diversity and the dynamic of the different yeasts present during the alcoholic fermentation. Must is generally rich in yeast species of the genera Hanseniaspora, Metschnikowia, Pichia, Torulaspora. There are then outcompeted by S. cerevisiae which dominates the active phase of fermentation. It is suggested that several environmental factors, as well as viticultural and winemaking practices can influence the microbial diversity. Due to the yeast diversity and the great variations in environmental conditions, it is often difficult to study the interaction mechanisms driving the microbial dynamics during fermentation. The development of a model consortia could help to analyse the microbial community more easily by reducing the number of species and using defined environmental conditions. Our work aims to build a model consortium of yeasts representing the diversity found during winemaking to study the impact of abiotic stress. We have selected 7 species representing the initial diversity of must and chosen according to bibliography their starting proportion. We show the labelling strategy that enables us to follow individually each species during fermentation by using different fluorescent protein detectable with a flow cytometer. This microbiological tool will be a great help to understand and experiment on the impact of diversity on the oenological fermentation.