Spectrum of antimicrobial activity of lactic acid bacteria (Lactobacillus KSBT 56) isolated from indigenous fermented products of Odisha

Abstract

The strain KSBT56 was isolated from a traditional fermented product ‘dahi chhenna’ of Odisha by pour plate method on MRS agar. Biochemical and 16s rDNA sequencing confirmed KSBT 56 as genus Lactobacillus. The cell-free supernatants (CFS) ofLactobacillus KSBT56 demonstrated an antibacterial activity against a wide range of Gram-negative and Gram-positive pathogens (Escherichia coli MTCC 82, Bacillus cereus ATCC10702, Salmonella spp. (Salmonella enteritidis 125109, Salmonella enterica serovar typhi MTCC 3216, Salmonella typhimurium SB300), Aeromonas hydrophila ATCC 7966, and Staphylococcus aureus MTCC 96. In contrast, it did not inhibit any lactobacilli tested. The putative metabolite produced by this organism was heat stable, sensitive to various pH values, a low molecular mass (<3000 Da) and either insensitive or low level sensitive to enzymatic treatments and require an acidic condition to develop. The compound resembles defensin more closely rather than bacteriocin and microcin. Key words: Lactic acid bacteria, antibacterial activity, indigenous product, bacteriocin, microcin, defensin.