Screening the optimal ratio of symbiosis between isolated yeast and acetic acid bacteria strain from traditional kombucha for high-level production of glucuronic acid

Glucuronic acid-a human detoxifying drug can be found in traditional kombucha which is a sweetened-black tea fermented by symbiotic microflora between yeast and acetic acid bacteria embedded within a microbial cellulose membrane. The main purpose of the study is to obtain the new designed symbiosis from the isolated yeasts and bacterial strains which can produce the high-level glucuronic acid kombucha and avoid unexpected microbial contaminants. The isolation, selection and identification showed the best initial combination ratio between Dekkera bruxellensis KN89 and Gluconacetobacter intermedius KN89 is 4Y (yeast):6A (acetic acid -bacteria) in number of living cell per milliliter which produced 175.8 mg L-1 glucuronic acid in 7-day fermentation (P < 0.05). This study also provides a basic understanding about fermentation kinetics of this symbiosis in order to control and enhance the final product at the critical time point (after 54 hrs of process). The findings of this study are practically relevant in producing a safe and glucuronic acid enriched kombucha. (C) 2015 Elsevier Ltd. All rights reserved.