title: Lactic acid bacteria: promising supplements for enhancing the biological activities of kombucha.
abstract: Kombucha is sweetened black tea that is fermented by a symbiosis of bacteria and yeast embedded within a cellulose membrane. It is considered a health drink in many countries because it is a rich source of vitamins and may have other health benefits. It has previously been reported that adding lactic acid bacteria (Lactobacillus) strains to kombucha can enhance its biological functions, but in that study only lactic acid bacteria isolated from kefir grains were tested. There are many other natural sources of lactic acid bacteria. In this study, we examined the effects of lactic acid bacteria from various fermented Vietnamese food sources (pickled cabbage, kefir and kombucha) on kombucha's three main biological functions: glucuronic acid production, antibacterial activity and antioxidant ability. Glucuronic acid production was determined by high-performance liquid chromatography-mass spectrometry, antibacterial activity was assessed by the agar-well diffusion method and antioxidant ability was evaluated by determining the 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity. Four strains of food-borne pathogenic bacteria were used in our antibacterial experiments: Listeria monocytogenes ATCC 19111, Escherichia coli ATCC 8739, Salmonella typhimurium ATCC 14028 and Bacillus cereus ATCC 11778. Our findings showed that lactic acid bacteria strains isolated from kefir are superior to those from other sources for improving glucuronic acid production and enhancing the antibacterial and antioxidant activities of kombucha. This study illustrates the potential of Lactobacillus casei and Lactobacillus plantarum isolated from kefir as biosupplements for enhancing the bioactivities of kombucha.
authors.affiliation: Center of Research and Technology Transfer, International University, Vietnam National University, Ho Chi Minh City, 70000 Vietnam ; School of Biotechnology, International University, Vietnam National University, Ho Chi Minh City, 70000 Vietnam.
authors.forename: Nguyen Khoi
authors.initials: NK
authors.lastname: Nguyen
authors.affiliation: School of Biotechnology, International University, Vietnam National University, Ho Chi Minh City, 70000 Vietnam.
authors.forename: Ngan Thi Ngoc
authors.initials: NT
authors.lastname: Dong
authors.affiliation: Department of Biotechnology, Faculty of Chemical Engineering, University of Technology, Vietnam National University, Ho Chi Minh City, 70000 Vietnam.
authors.forename: Huong Thuy
authors.initials: HT
authors.lastname: Nguyen
authors.affiliation: Center of Research and Technology Transfer, International University, Vietnam National University, Ho Chi Minh City, 70000 Vietnam ; School of Biotechnology, International University, Vietnam National University, Ho Chi Minh City, 70000 Vietnam.
authors.forename: Phu Hong
authors.initials: PH
authors.lastname: Le
keywords: 2,2-diphenyl-1-picrylhydrazyl; Antibacterial activity; Fermented tea; Glucuronic acid; Kombucha