Selection and Use of Wild Lachancea thermotolerans Strains from Rioja AOC with Bioacidificant Capacity as Strategy to Mitigate Climate Change Effects in Wine Industry

Abstract

Lachancea thermotolerans help increase the acidity of wines by producing L-lactic acid, which can serve as a strategy to mitigate the decrease in total acidity in wines promoted by climate change. The aim of the present paper is to test the capability of wine bioacidification of wild strains isolated from Rioja AOC. For this purpose, L. thermotolerans strains isolated from musts were used in mixed fermentation (co-inoculation and sequential inoculation) with Saccharomyces cerevisiae to determine the fermentation performance and L-lactic acid production, in both laboratory scale and pilot scale. Fermentation kinetics was evaluated, in addition to the final wine chemical composition and organoleptical properties. The results indicated that the isolated strains produced L-lactic acid; these effects were dependent on the strain and the inoculation strategy, being higher the effect in sequential inoculation (9.20 g/L) than in co-inoculation. This L-lactic acid production capacity was maintained at a pilot scale (4.65 g/L), in which the acidity increase was perceptible in the sensorial analysis, and an ethanol concentration decrease was also reported. The wine acidification depends on the appropriate selection of the strains, the inoculation procedure, the yeast adaptation to media, and competence with other yeast species present in the fermentation broth. The wild L. thermotolerans Lt97 strain could be used as a bioacidification tool for wines affected by climate change.