Bioprospecting and Selection of Indigenous Saccharomyces cerevisiae Yeasts from Pozo de Los Algarrobos (Argentina) for the Production of Genuine White Wines

Yeasts play a crucial role in the winemaking process contributing to the typicity and originality of wines in a region. Therefore, the aim of the present study was to isolate, characterize, and select yeasts from the Geographical Indication "Pozo de Los Algarrobos", San Juan, Argentina. Yeasts were directly isolated from grapes and at different stages of spontaneous fermentations of Vitis vinifera Viognier and Chardonnay varieties. Molecular and intraspecific identification of Saccharomyces cerevisiae yeasts was conducted using the D1/D2 domain and interdelta, respectively, observing 13 different yeast strains from Viognier and 12 from Chardonnay vinifications. Based on the enological traits assayed, two strains, V22 (Viognier) and C14 (Chardonnay), were selected for further studies. Microvinifications with these yeasts were carried out with Viognier and Chardonnay grape must in 2 L flasks, and the resulting wines were analytically and sensorially evaluated. Overall, strain V22 produced wines with positive and particular sensory properties, associated with fruity and floral aromas, color intensity, sweetness, aromatic persistence, and varietal typicity. Consequently, biomass propagation of V22 was conducted to inoculate pilot- (100 L) and industrial (12,000 L)-scale fermentations. V22 resulted in a correct wine fermentation performance obtaining a final product with distinctive and genuine properties.