Typical kombucha fermentation: Kinetic evaluation of beverage and morphological characterization of bacterial cellulose

The production of kombucha generates as products a fermented beverage and also bacterial cellulose (BC). Despite several studies on the production and characteristics of the beverage, BC from kombucha is still little explored and there are not many reports on the reuse of this material. The main objective of this study was to demonstrate typical kombucha fermentation results in a satisfactory amount of BC with morphological and physicochemical characteristics similar to those produced in synthetic medium. For this, the fermentation kinetics for obtaining kombucha beverage and BC were evaluated in a medium containing green tea and sugar. The microbial composition of the culture was identified and Komagataeibacter rhaeticus proved to be the main strain responsible for BC production. The fermentation showed typical behavior with the production of acetic acid, citric acid, ethanol, and a slight increase in total phenolic content (TPC) and antioxidant activity. The final concentration of 4.56 g/L of BC was obtained and identified as type I, showing a structure of fine tangled fibers and crystallinity of 74.3%. Knowing that there is a high demand for cellulose in many areas, BC produced by the kombucha industry can be an alternative source to the conventional production method. Novelty impact statement This study demonstrated that two products could be obtained in the typical kombucha fermentation, the beverage and the bacterial cellulose (BC). The results showed that considerable amounts of BC were produced with physicochemical characteristics comparable to BC produced by isolated strains in a synthetic medium.