Chloé ROULLIER-GALL1, V. David1, F. Bordet1, P. Schmitt-Kopplin2, H. Alexandre1
1 Université de Bourgogne, IUVV, Dijon, France
2 Technische Universität München, Freising Germany
Email contact: chloe.roullier-gall[@]u-bourgogne.fr
AIM: During alcoholic fermentation, when yeasts grow simultaneously, they often do not coexist passively and in most cases interact with each others . They interact by roducing unpredictable compounds an fermentation products that can affect the chemical composition of the wine and therfore alter its aromatic and sensory profile [1, 2].
METHODS: Chardonnay must inoculated with non-Saccharomyces yeasts including Lachancea thermotolerans, Starmerella bacillaris, Metschnikowia pulcherrima and later with Saccharomyces cerevisiae for sequential fermentation screened for metabolite composition using ultra high resolution mass spectrometry .
RESULTS: We show that tremendous differencces exist between yeasts in terms of metabolites production and we could clearly differentiate wines according to the yeast strain used . It appears that single cultures could be easily discriminated from sequential cultures based on their metabolite profile. Biomarkers, which reflect important differences between wines from single or mixed culture fermentation, were extracted and annotated to characterized yeast species impact on wine final composition. New metabolites appeared in wines from sequential fermentation and some others metabolites are not detected anymore compared to single cultures. Our data are consistent with the existence of positive or negative interactions between yeast species.
CONCLUSIONS: The wine composition from sequential culture is not only the addition of metabolites from each species but is the result of complex interactions suggesting that interactions between yeasts are not neutral. The level of metabolites represents integrative information to better understand the microbial interactome in order to control the fermentation by multi-starters.
 Bordet, F. et al. Yeast–Yeast Interactions: Mechanisms, Methodologiesand Impact on Composition. Microorganisms 8, 600 (2020). doi:10.3390/microorganisms8040600
 Petitgonnet, C. et al. Influence of cell-cell contact between L. thermotolerans and S. cerevisiae on yeast interactions and the exo-metabolome. Food Microbiology 83, 122 (2019). doi.org/10.1016/j.fm.2019.05.005
 Roullier-Gall, C. et al. Exploring yeast interactions through metabolic profiling. Sci Rep 10, 6073 (2020). doi.org/10.1038/s41598-020-63182-6