Native Yeasts and Lactic Acid Bacteria Isolated from Spontaneous Fermentation of Seven Grape Cultivars from the Maule Region (Chile)

Abstract

Grapes are a source of native yeasts and lactic acid bacteria (LAB); however, the microbialmake up is dependent on the grape cultivar and the regional growth conditions. Therefore, the aim ofthis study was to characterize the yeast and LAB in seven grape cultivars cultivated in Chile. Grapejuices were fermented at 25 C for 7 days. Samples were collected to analyze sugar, organic acids,and ethanol. Microbial evolution was measured with culture-dependent and molecular approaches.Then, a native isolated Candida oleophila was selected for further sequential fermentations withSaccharomyces cerevisiae. The grape cultivars in the Maule showed a diversity of non-Saccharomycesyeasts, with a greater diversity observed at the beginning of the fermentation. However, speciesfrom the Hansenasporia, Metschnikowia, Torulaspora, Lachancea, and Candida genera were detected after7 days, suggesting tolerance to environments rich in ethanol, capability may be associated to theterroir studied, which is characterized by torrid weather and antique and traditional vineyards. Thealcoholic fermentation negatively impacted the LAB population, and after 7 days only Leuconostocmesenteroides was isolated. In the sequential fermentations, C. oleophila was able to produce fermentedgrape juices with <1.5 g/L glucose, 12.5% (v/v) alcohol, and low concentrations of malic (0.3 (g/L). To our knowledge this is thefirst time C. oleophila has been reported as a potential starter culture for wine production. However,more studies are necessary to fully characterize the potential of C. oleophila on wine attributes.