Unlocking the oenological potential of native non-Saccharomyces yeasts from fruit microbiota

The use of indigenous non-Saccharomyces yeasts in the winemaking process highlights the microbiological terroir, which contributes to the authenticity and a unique regional character of wine. In this study, 33 isolates of non-Saccharomyces yeasts were isolated from the surface of ripe fruit from the territory of southern Serbia. The isolates were classified into four groups using cluster analysis based on their morphological and oenological characteristics. One isolate was chosen from each group for further analysis. The selected isolates were identified as Pichia kluyveri K-1, Hanseniaspora uvarum Kd-12, Rhodotorula glutinis Gf-3, and Papiliotrema laurentii C-1 by the API 20C AUX test. These isolates were used for the microvinification of the sterilized must from Prokupac grape, in order to assess their impact on the wine quality. In both fermentation protocols, pure and sequential, all the selected isolates resulted in a sample with acceptable organic acid profile, while P. kluyveri K-1 and H. uvarum Kd-12 showed the ability to produce ethanol, up to 7% vol. Two other isolates, R. glutinis Gf-3 and P. laurentii C-1, exhibited notable SO2 tolerance but were unable to initiate fermentation in pure culture, leaving residual sugars of 145.82 and 210.26 g/L, respectively. In contrast, within the sequential fermentation protocol, P. laurentii C-1 produces wine with 20% lower ethanol content and a markedly higher glycerol concentration when compared to the commercial yeast and all other used isolates. The obtained results provide significant support for the potential application of native yeast isolates in the winemaking process.