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- Patel, Ami, et al.
(författare)
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Evidence for xylooligosaccharides utilization in Weissella strains isolated from Indian fermented foods and vegetables.
- 2013
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Ingår i: FEMS Microbiology Letters. - : Oxford University Press (OUP). - 1574-6968 .- 0378-1097. ; 346:1, s. 20-28
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Six strains isolated from fermented food were by 16S rDNA sequencing identified as Weissella species, clustering with the species-pair W. confusa/ W. cibaria. The strains were analysed for growth on glucose, xylose and xylooligosaccharides (XOS). All strains were xylose positive using the API CHL 50 test. Growth on XOS was observed for strain 85, 92, 145 and AV1, firstly by optical density measurements in microtiter plates and secondly in batch cultures also confirming concomitant decrease in pH. Analysis of XOS before and after growth established consumption in the DP2 - DP5 range in the four XOS-fermenting strains. XOS were consumed simultaneously with glucose, while xylose was consumed after glucose depletion. Cell-associated β-xylosidase activity was detected in the XOS fermenting strains. Analysis of genomic data suggests this activity to be linked to genes encoding glycoside hydrolases from family 3, 8 or 43. No endo-β-xylanase activity was detectable. Main fermentation end products were lactate and acetate. A higher ratio of acetic acid/lactic acid was produced during growth on XOS compared to growth on glucose. This is the first report on utilization of XOS in Weissella, indicating an increased probiotic potential for XOS-utilizing strains from the species pair W. confusa/ W. cibaria, but also showing that XOS utilization is strain-dependent for these species. This article is protected by copyright. All rights reserved.
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| 3. |
- Patel, Ami, et al.
(författare)
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Probiotic properties of exopolysaccharide producing lactic acid bacteria isolated from vegetables and traditional Indian fermented foods
- 2012
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Ingår i: International Journal of Fermented Foods. - 2321-712X. ; 1:1, s. 87-101
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Tidskriftsartikel (refereegranskat)abstract
- A total of 203 lactic acid bacteria (LAB) isolated from vegetables and traditional fermented food products of India such as idli batter, dhokla batter and dahi were screened for exopolysaccharide (EPS) production. Based on the amount of EPS produced, 17 LAB isolates were selected for biochemical and genetic characterization using 16S rRNA gene sequencing. The isolates were belonging to the genera Lactobacillus, Weissella and Pediococcus. In vitro examination was performed to evaluate their probiotic potential. Resistance to low pH and 0.3 % bile salts was studied. Bile salt hydrolase (BSH) activity, susceptibility to various antibiotics and antimicrobial activity against the non pathogenic E. coli K12 were also investigated. The results showed that the isolates could not grow in the presence of oxbile however some survived exposure to it for 2.5 h. Some isolates were able to grow in the presence of sodium taurocholate and showed considerable antimicrobial activity against E. coli K12. Five isolates were showing BSH activity which is reported for the genus Weissella for the first time. The results suggest that traditional fermented products could be an alternative and readily available
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- Shah, Nihir, et al.
(författare)
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Determination of an antimicrobial activity of Weissella confusa, Lactobacillus fermentum, and Lactobacillus plantarum against clinical pathogenic strains of Escherichia coli and Staphylococcus aureus in co-culture
- 2016
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Ingår i: Annals of Microbiology. - : Springer Science and Business Media LLC. - 1590-4261 .- 1869-2044. ; 66:3, s. 1137-1143
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Tidskriftsartikel (refereegranskat)abstract
- Lactic acid bacteria (LAB) have long been used to produce safe and high quality products as they are potential producers of a wide range of antimicrobial compounds that exert either narrow or wide spectrum antimicrobial activity towards spoilage or disease-causing organisms. The present investigation aimed to study the antimicrobial effect of three LAB strains, viz., Lactobacillus plantarum (86), Lactobacillus fermentum (AI2) and Weissella confusa (AI10), against two clinical pathogenic strains viz., Escherichia coli NG 502121 and Staphylococcus aureus AY 507047 in co-culture. Effects of change in inoculum size, and growth measurement at different time intervals were also studied. The pH and viable count were measured for initial as well as 24 h incubated samples. A significant (P < 0.05) reduction (2–3 log cycles) in growth of both pathogens while co-cultured with LAB strains was observed. The nonsignificant (P < 0.05) pH difference revealed the action of other metabolites apart from organic acids. LAB strains overruled the growth of E. coli and S. aureus within 10 and 6 h of the initial growth stage, respectively, compared to controls. These results led us to further characterize and purify the antimicrobial compound produced by the studied strains, so that they can be exploited in the production of safe foods with longer shelf life.
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