Profiling Potential Wine Yeast Starters from Criolla Grape Varieties from Argentina

Criolla grape varieties are native South American cultivars that represent an important reservoir of genetic and microbiological diversity. This study aimed to investigate the oenological potential of Saccharomyces and non-Saccharomyces yeasts isolated from three criolla grape varieties in order to support the future design of wine starters. Yeasts were isolated at different fermentation stages from four vineyards in Mendoza, Argentina. A total of 485 isolates were recovered and molecularly identified, revealing 12 species belonging to eight genera. Saccharomyces cerevisiae, Hanseniaspora guilliermondii and Hanseniaspora uvarum were the dominant species. Isolates were screened for H2S and acetic acid production, followed by physiological and enzymatic characterisation. Selected strains were further evaluated in small-scale fermentations to assess fermentative kinetics and metabolic performance. Significant variability was observed, particularly among non-Saccharomyces isolates, which generally exhibited lower ethanol yields and acetic acid production compared to S. cerevisiae. Several isolates of H. guilliermondii showed balanced fermentative behaviour and favourable metabolic and enzymatic profiles. Through the applied selection strategy, twelve strains emerged as promising wine starter candidates. These isolates combined a low production of undesirable metabolites, relevant enzymatic activities, and favourable fermentative performance. Overall, the results highlight the oenological potential of autochthonous yeasts as a resource for innovative winemaking strategies.