Enhanced volatile phenols in wine fermented with Saccharomyces cerevisiae and spoiled with Pichia guilliermondii and Dekkera bruxellensis

Aims: To investigate whether the presence of Pichia guilliermondii impacts on the production of volatile phenols from mixed wine fermentations with Dekkera bruxellensis and Saccharomyces cerevisiae. Methods and Results: Four inoculation strategies were performed in small-scale fermentations involving P. guilliermondii, D. bruxellensis and S. cerevisiae using Syrah grape juice supplemented with 100 mg l-1 of p-coumaric acid. High pressure liquid chromatography was used for the quantification or volatile phenols. Significant high levels of 4-ethylphenol and 4-ethylguaicol (720 and 545 mu g l-1, respectively), as well as the highest levels of 4-vinylphenol (> 4500 mu g l-1), were observed when P. guilliermondii species was inoculated from the beginning of the fermentation. Conclusions: The metabolic interaction occurring between the high vinylphenol producer species P. guilliermondii and D. bruxellensis exhibiting a high vinylphenol reductase activity resulted in an increased production of volatile phenols in wine. Significance and Impact of the Study: Pichia guilliermondii must be considered a very important spoilage yeast in the wine industry capable of producing large amounts of volatile phenols.