Overview of Dekkera bruxellensis behaviour in an ethanol-rich environment using untargeted and targeted metabolomic approaches

Dekkera bruxellensis is a yeast known for its ability to produce ethyl phenols from hydroxycinnamic acid in wine, affecting the quality of its flavour. In wine, D. bruxellensis is not responsible for producing ethanol, however it is able to survive and sometimes also to grow in the presence of large amounts of ethanol. Because of its endurance, D. bruxellensis poses a serious threat to the wine industry and can cause substantial financial losses. In order to analyse yeast activity in the presence of different amounts of ethanol, the metabolic profile of a D. bruxellensis strain isolated from wine was outlined in defined chemical conditions in model wines. The metabolic profile of model wines with 10%, 11%, and 12% ethanol after D. bruxellensis growth was studied. Several ethyl esters and phenyl ethanol, together with 4-ethyl guaiacol, were produced in significantly higher amounts in response to the increase in ethanol stress. It was shown how the cell metabolism of specific compounds increased in response to a higher ethanol content, although yeast cell growth was limited.