Evolution of Kombucha Tea from Isolated Acetic Acid Bacteria, Lactic Acid Bacteria and Yeast in Single- and Mixed-Cultures: Characteristics, Bioactivities, Fermentation Performance and Kinetics

In this study, three microbial isolates from kombucha (Saccharomyces cerevisiae, Komagataeibacter saccharivorans, and Levilactobacillus brevis) were used as single- and mixed-inoculum to produce kombucha. During 18-day fermentation, phenolic content was shown to rise from 621.4–633.1 to 817.8–937.7 mg/L while DPPH radical scavenging and ferric reducing activities reached their peaks (1191.3–1343.3 and 742.9–837.9 mg/L, respectively) at day 2–8 and constantly declined throughout the remaining days. Higher sugar concentration and longer fermentation time also resulted in greater antibacterial activity, particularly against Gram-positive bacteria. Regarding bacterial cellulose productivity, 50 g/L glucose was proven to be the effective concentration regardless of microbial combinations with the maximum yield of 193.3–263.9 g/L. A close interaction was seen between S. cerevisiae and K. saccharivorans, while L. brevis exhibited limited interaction with others. Therefore, the application of single culture of K. saccharivorans, or its mixed-culture with S. cerevisiae is considered a feasible approach to control Kombucha quality.