Analysis of Antimicrobial Activity of Lactobacillus paracasei ssp. paracasei-1 Isolated from Regional Yogurt

Lactic acid bacteria are very significant to human health due to the production of some antimicrobial substances and ability to inhibit pathogenic bacteria. In this study, Lactobacillus strains were isolated from yogurts of Khulna region, Bangladesh and identified as Lactobacillus paracasei ssp. paracasei-1. The antimicrobial activity of cell free supernatant was tested against both gram positive and gram negative pathogenic bacteria and found to be sensitive. The supernatant exhibited tolerance to extreme pH and was heat stable as well as sensitive to proteolytic treatment. The latter property could be attributed to a bacteriocin like inhibitory substance (BLIS) secreted from L. paracasei ssp. paracasei-1. In addition, the isolate showed good survival in presence of a number of bile salts indicating its potential application as probiotic supplement.