Effects of Lactobacillus casei and Alterations in Fermentation Conditions on Biosynthesis of Glucuronic Acid by a Dekkera bruxellensis-Gluconacetobacter intermedius Kombucha Symbiosis Model System

Abstract

A combination of Dekkera bruxellensis and Gluconacetobacter intermedius is used as a model system to emulate the microbial symbiosis between yeast and acetic acid bacteria in kombucha, and to study glucuronic acid (GlcUA) production in this system. In the current study, the addition of Lactobacillus casei and variations in the fermentative conditions, such as sucrose concentration, temperature and duration, were examined to evaluate their effects on GlcUA formation. Results showed that L. casei acts as a supporter species and stimulated GlcUA production in the kombucha symbiosis model to levels 54.1% greater than in the control. Varying the fermentation parameters also affected GlcUA production. Therefore, the range of each factor value was screened and restricted to achieve a higher amount of target acid, as it was 5–15%, 25–31°C, 3–7 days, and 5–7 units in sucrose concentration, temperature, fermentation time and initial pH value, respectively. These findings are an important step for optimizing GlcUA production by this model system.