Elucidating the relationship between microbial communities and the formation of flavour metabolites in Cabernet Sauvignon wine through metagenomic analysis

The unique flavour and quality of wine largely depend on its complex fermentation process, which in turn is significantly influenced by the microbial activities during fermentation. In this study, we investigated the relationship between the microbiota and the formation of main metabolites during the spontaneous fermentation of Cabernet Sauvignon wine. The main metabolites during the spontaneous fermentation of Cabernet Sauvignon wine were identified through headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry and high-performance liquid chromatography, and metagenomic sequencing was used to characterize the succession and potential metabolic capabilities of the microbial communities throughout the fermentation process. The results showed that as the alcoholic fermentation progressed, there was a significant increase in the relative abundance of Saccharomyces, dominating the alcoholic fermentation, and concurrently, there were notable changes in the structure of the microbial community. The genera Saccharomyces, Hanseniaspora, Tatumella, and Oenococcus showed potential correlations with the biosynthesis of the main metabolites such as alcohols, acids, and esters, in wine. Particularly, Saccharomyces, as the primary driver of alcoholic fermentation, was closely related to the biosynthesis of these metabolites. Overall, our study advances the comprehension of the functional role and metabolic contributions of microbial communities in shaping the flavour profile during fermentation.