Abstract
We applied targeted metabolic inhibitors to 145 Lachancea thermotolerans strains to uncover fermentation traits with direct relevance to wine quality. Oxamate, a lactate dehydrogenase inhibitor, reduced lactic acid and total titratable acidity by 21% and 26%, respectively, while increasing succinic acid and pH without affecting ethanol levels, offering a promising strategy to fine-tune wine freshness and balance. Notably, industrial grape-associated strains (clusters C4-C6) maintained robust growth under oxamate stress, unlike wild strains, positioning oxamate resistance as a practical marker for selecting high-performing, acidifying yeasts for winemaking. Additional inhibitors such as metformin shifted redox metabolism, significantly enhancing glycerol (+25%) and acetic acid (+319%) production. Transcriptomic analyses showed that OXA alone, and even more so the DSF + OXA combination, repressed LDH2 and upregulated GPD1 and oxidative phosphorylation genes, whereas MET caused only moderate changes. This integrated phenomic-transcriptomic approach not only provides valuable tools for yeast screening but also defines a roadmap for optimizing wine composition through the precision selection of L. thermotolerans strains.