Oenological Potential of Lachancea thermotolerans and Hanseniaspora uvarum from High-Sugar Musts: Impacts on Fermentation and Wine Volatilome

Currently, there is little scientific data to support the importance of selecting non-<i>Saccharomyces</i> yeasts from different wineries in the Protected Designation of Origin (PDO) in Andalusia, southern Spain, and how this group of yeasts can affect the sensory properties of wine. Therefore, this research aimed to study some specific microbiological properties and the metabolites they could produce in order to evaluate the oenological potential of two non-<i>Saccharomyces</i> yeast strains isolated from a region of Andalusia (Córdoba, Spain), <i>Hanseniaspora uvarum</i> TJ-27 and <i>Lachancea thermotolerans</i> T-9, isolated from musts with high sugar content. Of 80 yeast isolates selected, these two strains were chosen for their notable β-glucosidase activity (observed in up to 40% of isolates), cellulase activity (present in 24%), and killer phenotype (found in 40%). In this study, strains that displayed characteristics associated with aroma release were selected. Fermentation assays using a high-sugar synthetic medium revealed that neither <i>H. uvarum</i> TJ-27 nor <i>L. thermotolerans</i> T-9 was able to complete alcoholic fermentation independently, achieving ethanol yields of only 5-6% <i>v</i>/<i>v</i>, indicating the need for subsequent fermentation by <i>Saccharomyces cerevisiae</i>. The originality of this study provides insight into the metabolites contributed by these strains to the wines produced. The best results were obtained when both strains were inoculated together. Furthermore, volatilome analysis showed elevated levels of key compounds such as isoamyl alcohols and 2,3-butanediol. These findings highlight the practical potential of using selected non-<i>Saccharomyces</i> strains from Andalusia to improve fermentation results and wine quality. The novelty of this study lies mainly in confirmation within region-specific isolates.