Selection and characterization of a Patagonian Pichia kudriavzevii for wine deacidification

Aims: The purpose of this study was to select autochthonous yeasts with metabolic ability to degrade L-malic acid for its potential use in young wine deacidification. Methods and Results: Fifty seven Patagonian nonSaccharomyces yeast of oenological origin were identified by conventional molecular methods and tested in their capability to grow at the expense of L-malic acid. Only four isolates belonging to Pichia kudriavzevii species showed this property, and one of them was selected to continue with the study. This isolate, named as P. kudriavzevii (N) over tilde NI15, was able to degrade L-malic acid in microvinifications, increasing the pH 0.2-0.3 units with a minimal effect on the acid structure of wine. Additionally, this isolate produced low levels of ethanol, important levels of glycerol (10.41 +/- 0.48 g l(-1)) and acceptable amounts of acetic acid (0.86 +/- 0.13 g l(-1)). In addition, it improved the sensorial attributes of wine increasing its fruity aroma. Conclusions: The selection of yeasts for oenological use among nonSaccharomyces species led to the finding of a yeast strain with novel and interesting oenological characteristics which could have significant implications in the production of well-balanced and more physicochemical and microbiological stable young wines. Significance and Impact of the Study: The use of P. kudriavzevii (N) over tilde NI15 as mixed starter with S. cerevisiae would eliminate the cultural and cellar operations undertaken to adjust the musts acidity, therefore improving wine quality and reducing production costs.