A Comprehensive Review of Kombucha Fermentation and Probiotic Functional Mechanisms: Microbial Dynamics, Bioactive...

The rising demand for health-promoting beverages, kombucha presents significant opportunities for scientific innovation and commercial growth. Symbiotic culture of bacteria and yeast (SCOBY), which includes acetic acid bacteria (AAB), lactic acid bacteria (LAB), and several yeast species, plays a major role in kombucha fermentation. During fermentation, kombucha produces bioactive compounds mainly catechins, theaflavins, tannins, and organic acids that enhance health efficacy and probiotic properties, supporting gut health and non-communicable disease prevention. The present study emphasizes, nutritional qualities of kombucha through different Komagataeibacter starter cultures and alternative substrates such as herbal infusions and fruit extracts. This review also highlights the role of AAB, LAB, and Yeast in the production mechanism of the kombucha beverage by the different microbial strains of microbial species and the fibril network of bacterial cellulose. This study further explains the bioactivities in the human body, especially mechanisms of action in the intestine through fundamental signaling pathways such as PIK3-AKT, MAPK, NFκB, PPARγ, and JAK-STAT. Therapeutic efficacy of kombucha, including various substrate-based antioxidants, antimicrobials, synergistic impact, delivery mechanism of anticancer, anti-diabetic insulin, and glycaemic responses, regulations of inflammatory markers (ILs) in anti-obese properties, has also been reviewed. Further, it is necessary to develop the advanced kombucha beverage qualities through metagenomics, metabolomics. Future studies should address these research gaps to ensure controlled microbial and probiotic stability, validate metabolites availability, and explore innovative applications for improved functionality and shelf-life.