Comparative Analysis of Microbial Communities and Biopolymer Production in Kombucha.

While the microbial diversity of kombucha has been previously investigated, only a limited number of studies have explicitly distinguished between the symbiotic culture of bacteria and yeast (SCOBY) and the liquid broth, and even fewer have directly associated microbial diversity with bacterial cellulose production. This study investigated the microbial communities present in commercially available kombucha products by using both culture-based and molecular analysis methods, along with metabolite profiling by chemical analyses. Culture-based methods identified key cellulose-producing strains, including Komagataeibacter intermedius, K. rhaeticus, and Novacetimonas hansenii, while next-generation sequencing revealed Komagataeibacter as the dominant bacterial genus in kombucha. Yeast communities in kombucha were predominated by Zygosaccharomyces bisporus and Z. parabailii. As fermentation progressed, all kombucha samples exhibited typical fermentation dynamics, characterized by progressive sucrose depletion and an increase in ethanol and acetate production. Given the promising industrial applications of bacterial cellulose, the biopolymer content of kombucha was evaluated. Among the kombucha samples, K2 showed the highest cellulose yield (4.50 ± 2.28 g), and N. hansenii was identified as the most efficient cellulose producer among the isolates. This integrative approach provides critical insights into the role of microbial communities in regulating kombucha fermentation. Specifically, this study delineated the core microbiota required for stable fermentation and identified strains with enhanced cellulose-producing capacity. Beyond defining the key microbial taxa associated with kombucha production, these findings underscore the industrial potential of kombucha-derived cellulose producers and present a strategy for optimizing bacterial cellulose yield in large-scale applications.