| Popis: |
BackgroundProbiotic, Lactic Acid Bacteria (LAB) are consumed by human through the traditional food products for several decades due to their beneficial health effects. LAB is Gram positive, non motile bacteria that produce antimicrobial peptides for their defense mechanism. Among the antimicrobial peptides, Bacteriocins are widely investigated because of their possible utilization in food sector especially food security actions, where bacteriocin kills or inhibits the growth of other bacteria. Usage of metabolic products of LAB and LAB are generally recognized as safe. Therefore, this study was aimed to isolate LAB species that produce bacteriocin showing wide spectrum antibacterial activity.Results Lactic acid bacteria were isolated from yoghurt, curd, dosa batter, idli batter and soaked and ground rice batter using (De Man, Rogosa and Sharpe agar) MRS agar and incubated at room temperature (30±2ºC) for 24-72 h aerobically and anaerobically. When agar well diffusion method was employed to detect the antibacterial activity of the twenty five isolates against food spoilage organisms (Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, E.coli, Klebsiella pneumoniae, Serratia marcescens, Salmonella sp., Proteus sp., Micrococcus sp., and Bacillus sp.,). Three bacterial species showing broad spectrum of antibacterial activity, were identified and characterized by biochemical and molecular methods. The wide spectrum antibacterial bacterial species were identified as Lactobacillus reuteri AF182723 isolated from curd, Lactobacillus rhamnosus AY299488 isolated from rice batter and Lactobacillus acidophilus AF182726 isolated from yoghurt. Among all the isolates, Lactobacillus reuteri AF182723 showed significant wide spectrum antibacterial activity against diverse Gram positive and Gram negative bacterial species. Conclusion The production of bacteriocin from Lactobacillus reuteri AF182723 and incorporating it in the food would inhibit the food spoilage organisms. Usage of this bacteriocin at appropriate concentration in food needs to be studied further. |
