Résumé
The yeast Brettanomyces bruxellensis is known as a spoilage yeast of red wines and other fermentedbeverages by producing unpleasant volatile phenols. These compounds derive from the precursorhydroxycinnamic acids (HCA), which are naturally present in grape must, and impart horse-likearomas to the wine. A major challenge for winemakers is to avoid Brettanomyces proliferation incellars to prevent the formation of volatile phenols. However, to date, only a few studies focused onBrettanomyces bruxellensis physiology and in particular, the toxicity of hydroxycinnamic acidsremains poorly understood. In this context, our study aimed to elucidate the potential relationshipsbetween hydroxycinnamic acid content and nature, and yeast fitness in a winemaking environment.The growth and viability of 24 B. bruxellensis from the 8 different genetic groups were monitored byflux cytometry during anaerobic cultures on synthetic wine. The p-coumaric acid appeared to bemore toxic than caffeic and ferulic acids. Interestingly, the evolution of viability and growth does notappear to differ significantly between genetic groups, but varies between strains. At a concentrationof hydroxycinnamic acid as low as 0.35 mM, the most sensitive strains were affected in their viabilityfrom the start of the culture, while the most resistant strains only presented a limited growth. Theresults also indicate a dose effect, underlining the relative resistance of several strains to lowconcentrations of HCAs. However, concentrations above 0.7 mM of p-coumaric acid induced a strongdecrease in both viability and growth of all B. bruxellensis strains. By mimicking winemakingconditions, this study sheds new light on the presence and persistence of B. bruxellensis in cellars.We demonstrate that HCAs exhibit toxicity towards this yeast, paving the way for novel strategies toface wine spoilage