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Title: Potential probiotic strains from milk and water kefir grains in Singapore—use for defense against enteric bacterial pathogens
Authors: Tan, Li Ling
Tan, Chuan Hao
Ng, Noele Kai Jing
Tan, Yoke Hun
Conway, Patricia Lynne
Loo, Joachim Say Chye
Keywords: Science::Biological sciences::Microbiology
Issue Date: 2022
Source: Tan, L. L., Tan, C. H., Ng, N. K. J., Tan, Y. H., Conway, P. L. & Loo, J. S. C. (2022). Potential probiotic strains from milk and water kefir grains in Singapore—use for defense against enteric bacterial pathogens. Frontiers in Microbiology, 13, 857720-.
Project: MOE/RCE: M4330019.C70 
RT08/19 (S) 
Journal: Frontiers in Microbiology 
Abstract: Kefir grains consist complex symbiotic mixtures of bacteria and yeasts, and are known to impart numerous health-boosting properties to milk and water kefir beverages. Accordingly, studies have been conducted to investigate the microbiota communities in kefir grains, as well as the possibility of deriving useful probiotic strains from them. This study began with milk and water kefir grains collected from a Singapore-based homebrewer, and a total of 158 microbial strains, representing 6 fungal and 17 bacterial species, were isolated from these. Isolated genera include Lactobacillus, Liquorilactobacillus, Lacticaseibacillus, Lentilactobacillus, Leuconostoc, Lactococcus, Acetobacter, Gluconobacter, Oenococcus, Clostridium, Zymomonas, Saccharomyces, Kluyveromyces, Pichia, Lachancea, Candida and Brettanomyces. Next, a funnel approach, involving numerous phenotypic and genomic screening assays, was applied to identify kefir-derived microbial strains with highest probiotic potential. Particular focus was placed on examining the antipathogenic properties of kefir isolates towards enteric pathogens, which pose considerable global health burden. Enteric pathogens tested include from the genera Bacillus, Salmonella, Vibrio, Clostridium, Klebsiella, Escherichia and Staphylococcus. Well diffusion assays were conducted to determine the propensity of kefir isolates to inhibit growth of enteric pathogens, and a competitive adhesion/exclusion assay was used to determine the ability of kefir isolates to out-compete or exclude attachment of enteric pathogens to Caco-2 cells. Seven bacterial strains of species Lentilactobacillus hilgardii, Lacticaseibacillus paracasei, Liquorilactobacillus satsumensis, Lactobacillus helveticus and Lentilactobacillus kefiri, were ultimately identified as potential probiotics. Desirable probiotic characteristics, including good survival in acid and bile environments, bile salt hydrolase activity, antioxidant activity, non-cytotoxicity and high adhesion to Caco-2 cells, lack of virulence or antimicrobial resistance genes and presence of vitamins and GABA synthesis genes, were identified in these kefir isolates. Overall, probiotic candidates derived in this study are novel strains which can add diversity to the existing probiotics repertoire, and may also provide consumers with alternative product formats to attain the health benefits of kefir.
ISSN: 1664-302X
DOI: 10.3389/fmicb.2022.857720
DOI (Related Dataset): 10.21979/N9/9TG8JH
Schools: School of Materials Science and Engineering 
Lee Kong Chian School of Medicine (LKCMedicine) 
Research Centres: Singapore Centre for Environmental Life Sciences and Engineering (SCELSE) 
Rights: © 2022 Tan, Tan, Ng, Tan, Conway and Loo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:LKCMedicine Journal Articles
MSE Journal Articles
SCELSE Journal Articles

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