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Tan LL, Tan CH, Ng NKJ, Tan YH, Conway PL, Loo SCJ. Potential Probiotic Strains From Milk and Water Kefir Grains in Singapore—Use for Defense Against Enteric Bacterial Pathogens. Front Microbiol 2022; 13:857720. [PMID: 35432232 PMCID: PMC9011154 DOI: 10.3389/fmicb.2022.857720] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 02/15/2022] [Indexed: 12/15/2022] Open
Abstract
Kefir grains consist of complex symbiotic mixtures of bacteria and yeasts, and are reported to impart numerous health-boosting properties to milk and water kefir beverages. The objective of this work was to investigate the microbial communities in kefir grains, and explore the possibility of deriving useful probiotic strains from them. A total of 158 microbial strains, representing six fungal and 17 bacterial species, were isolated from milk and water kefir grains collected from a Singapore-based homebrewer. Based on 16S rRNA sequencing, isolated genera included Lactobacillus, Liquorilactobacillus, Lacticaseibacillus, Lentilactobacillus, Leuconostoc, Lactococcus, Acetobacter, Gluconobacter, Oenococcus, Clostridium, Zymomonas, Saccharomyces, Kluyveromyces, Pichia, Lachancea, Candida, and Brettanomyces. To characterize these isolates, a funnel approach, involving numerous phenotypic and genomic screening assays, was applied to identify kefir-derived microbial strains with the highest probiotic potential. Particular focus was placed on examining the pathogen inhibitory properties of kefir isolates toward enteric pathogens which pose a considerable global health burden. Enteric pathogens tested include species of 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 Lentilactobacillus hilgardii, Lacticaseibacillus paracasei, Liquorilactobacillus satsumensis, Lactobacillus helveticus, and Lentilactobacillus kefiri, were ultimately identified as potential probiotics, and combined to form a “kefir probiotics blend.” 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, and a lack of virulence or antimicrobial resistance genes. In addition, vitamin and γ-aminobutyric acid (GABA) synthesis genes, were identified in these kefir isolates. Overall, probiotic candidates derived in this study are well-characterized strains with a good safety profile which can serve as novel agents to combat enteric diseases. These kefir-derived probiotics also add diversity to the existing repertoire of probiotic strains, and may provide consumers with alternative product formats to attain the health benefits of kefir.
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Affiliation(s)
- Li Ling Tan
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Chuan Hao Tan
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Noele Kai Jing Ng
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Yoke Hun Tan
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Patricia Lynne Conway
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Say Chye Joachim Loo
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
- *Correspondence: Say Chye Joachim Loo,
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The ecology of Zymomonas: a review. Folia Microbiol (Praha) 2016; 61:385-92. [PMID: 26803757 DOI: 10.1007/s12223-016-0447-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 01/14/2016] [Indexed: 10/22/2022]
Abstract
Zymomonas mobilis is a Gram-negative bacterium studied primarily as a spoilage organism and ethanol producer. As with many bacteria, much remains to be learned about its ecology. It can serve as a model organism for examining microbial interactions, as well as interactions between plants and bacteria. Better understanding of its ecology can help with biotechnological applications, such as process improvement, new uses of the bacterium, and the search for new strains.
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Abstract
Brewing beer involves microbial activity at every stage, from raw material production and malting to stability in the package. Most of these activities are desirable, as beer is the result of a traditional food fermentation, but others represent threats to the quality of the final product and must be controlled actively through careful management, the daily task of maltsters and brewers globally. This review collates current knowledge relevant to the biology of brewing yeast, fermentation management, and the microbial ecology of beer and brewing.
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Affiliation(s)
- Nicholas A. Bokulich
- Department of Food Science and Technology, University of California, Davis, California, USA
- Department of Viticulture and Enology, University of California, Davis, California, USA
| | - Charles W. Bamforth
- Department of Food Science and Technology, University of California, Davis, California, USA
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