Microbial–physicochemical integrated analysis of kombucha fermentation

Kombucha is a drink produced by spontaneous fermentation, and several studies have been conducted to unveil its microbiological and physicochemical aspects with numerous human health claims. The integration of these results is fundamental to understand and discuss the biological activities attributed to kombucha. In the present study, we isolated bacteria and yeasts involved in the fermentation of kombucha produced with green (GK) and black (BK) teas, as well as the amplicon metagenomic of the microbial communities (16S and ITS) during 0, 3, 5, 10, and 15 days of fermentation, at 28 °C. Microbial communities were linked to key biochemical parameters monitored during fermentation such as pH, total titratable acidity, total reducing sugars, polyphenols, acetic acid, and ethanol production. Moreover, ordination analysis (principal component analysis, PCA) revealed clear GK and BK separation groups during the fermentation process. Caffein, gallic acid, and chlorogenic acids majorly influenced the separation of GK and BK. Furthermore, the presence of Komagataeibacter spp. and catechins exerted selective pressure against microbial contamination. This study essentially contributes to the knowledge about the effects of integrated microbiota to the chemical results of the kombucha fermented in GK and BK teas.