Caracterização microbiológica do kombucha: efeitos dos açúcares e fermentação no microbioma oral e seu potencial probiótico

Abstract

Kombucha (KB) is an Asian fermented beverage made from the fermentation of SCOBY in teas from Camellia sinensis and is recognized for its probiotic and antioxidant properties. However, its effectiveness in controlling oral diseases such as dental caries is limited by the use of sugars, especially sucrose, to which exposure is a necessary and determining factor in the development of the disease. The aim of this study was to determine the microbiological composition of KB fermented in green tea for 4, 8 and 12 days using different sugars: sucrose 10% (m/v), glucose 10% (m/v), fructose 10% (m/v), mixture of 5% glucose + 5% fructose (m/v) and 10% sucralose (m/v). Amplicon sequencing was used for bacteria with the 16S gene and for fungi with the 18S gene (16S rRNA region V4 and 18S rRNA region V9, respectively) for a more detailed understanding of the microbiome in the probiotic. Green tea was prepared at a concentration of 6.4% (m/v) in water and infused for 15 minutes. The extracts were inoculated with 10% SCOBY and 10% of the selected sugar and fermented for 4, 8 or 12 days. Samples were cultured on solid media such as Blood Agar to count total viable microorganisms, Sabouraud Dextrose to count yeast, Man Rogosa and Sharpe to count lactic acid bacteria. Statistical analysis using GraphPad Prism 10 showed that microbial growth varied over the days with glucose and fructose and decreased after 12 days. Molecular analyses showed that sucralose was less effective in improving microbial proliferation, with lower richness and diversity, while sucrose, glucose, and fructose promoted microbial growth. On days 4 and 8, glucose, fructose and sucrose showed greater richness, diversity and abundance of microorganisms compared to other sugars and days of fermentation. After 12 days, mainly microbial families for fermentation and cellulose production were observed with low diversity. The present genera found in the analyses were Lactobacillus, Acetobacteraceae, Komagataeibacter (16S) and Brettanomyces, Saccharomycetaceae (18S).