Document Type : Research Article
Authors
1
Graduated student, Department of Microbiology, Gorgan branch, Islamic Azad University, Gorgan, Iran
2
Department of Microbiology, Azadshahr Branch, Islamic Azad University, Azadshahr, Golestan , Iran
3
Department of Microbiology, Gorgan branch, Islamic Azad University, Gorgan, Iran
Abstract
Antibacterial activity against gastrointestinal bacteria, tolerance to acidic conditions and bile salts are the main indicators of probiotics. The aim of this study was isolation of lactic acid bacteria with probiotic potential of bovine colostrum. Colostrum samples were cultured on selective culture. Identification of lactic acid bacteria carried out by biochemical tests of fermentation of sugars, growth at 10 and 45°C and 6.5% salt. Antagonistic effect of culture supernatant of isolates against native isolates S. aureus, E. coli, P. aeruginosa, B. cereus and standard strains E. coli, P. aeruginosa, S. dysentriae, S. aureus, B. cereus and E. faecalis carried out by well method and tolerance of isolates to acidic conditions and bile salts were evaluated. L. plantarum was the most species of isolated lactic acid bacteria (36.32%). Culture supernatant of L. plantarum more than other isolates was showed antibacterial activity. None of the isolates were able to grow at pH 2, but L. plantarum, L. casei, L. acidophilus, S. thermophilus and E. faecalis were able to tolerate pH of 3. Also, L. plantarum, L. casei, E. faecalis and E. faecium were able to grow in presence of 0.3 and 1% bile salt. Colostrum as a traditional dairy food can be considered as a very suitable reservoir for isolation of lactic acid bacteria with probiotic potential. Due to significant antibacterial activity of L. plantarum and the ability to grow in acidic condition and various concentrations of bile salts, probiotic potential of this isolate was evaluated as desirable.
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