Isolation and Screening of Lactobacillus Bacteria for Ability to Produce Antibiotics

Antibiotic is one of the important commercially exploited secondary metabolites produced by bacteria and used in a wide range. Most of the antibiotics used today are isolated from the microbes. Bacteria are easy to culture, isolate, maintain and to improve their strain. Isolation of lactic acid bacteria (LAB) from soil, yoghurt and cheese was carried out. LAB were cultivated on De Man Rogosa Sharpe (MRS) agar and were characterized based on colony morphology, cell shape and biochemical tests. Out of eight samples analyzed, 96 isolates were identified as LAB. The bacterial isolates were identified as Lactococcus Lactis, Lactobacillus Brevis, Lactobacillus casei, Pediococcus damnosus, Lactobaciilus rhamnosus, Lactobacillus Plantarum, Lactobacillus pentosus, Enterococcus feacalis, Staphylococcus Simulans.Using MRS broth, the isolated LAB were screened for production of bacteriocins. Further, 96 LAB screened for bacteriocin production, 12 LAB were identified as bacteriocin producers. Out of 12 LAB, Enterococcus faecium (CST-1) was identified as potential bacteriocin producer against Bacillus subtlis MTCC-10403 Pseudomonas aureginosa MTCC-4676 microorganisms used while Pediococcus damnosus had the least bacteriocin activity against Staphylococcus aureus and Bacillus subtilis.