Antibacterial activity and bioactive compounds of probiotic kombucha

The distinct characteristics of kombucha are influenced by the types of tea, sugar, and the microbial communities involved in fermentation. This study aimed to identify key metabolites in kombucha co-fermented with the probiotic yeast Saccharomyces boulardii EV16. Liquid chromatography-mass spectrometry (LC-MS) analysis revealed the presence of major bioactive compounds, including phenylpropanoids, polyketides, benzenoids, organic nitrogen and oxygen compounds, organic acids and derivatives, lipids, and lipid-like molecules, in kombucha with added yeast probiotics compared to the control. Antioxidant and antimicrobial activities were assessed using 2,2 diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and agar well diffusion assays, respectively. While the radical scavenging activity was comparable between both conditions, the antimicrobial activity measured by inhibition of Escherichia coli was significantly enhanced with the addition of yeast probiotics, showing a 40% and 37% increase in inhibition zones after 7 and 14 days of fermentation, respectively. These findings highlight the benefits of yeast probiotics in kombucha, particularly through the enhancement of its antimicrobial properties.