Isolation and Identification of Lactobacilli From Cheese, Yoghurt and Silage by 16S rDNA Gene and Study of Bacteriocin and Biosurfactant Production

Background: The Lactobacilli belong to lactic acid bacteria, whose primary fermentation end product from sugars is lactic acid and that is why foods are conserved. Lactic acid bacteria have been used for millennia in the production of silage. Therefore, they are an indispensable part of intestinal microflora in human and animals. Objectives: This research meant to isolate lactic acid bacteria with significant effects from different environments. Materials and Methods: In this study, heterofermentative LAB were isolated from cheese, yoghurt and corn silage in Broujerd ,Iran. The standard biochemical methods were applied. Acid tolerance was studied by exposure to acidic PBS and growth in bile salt was measured by the spectrophotometric method. The isolated bacteria were studied for antagonistic effects on environment isolated E.coli, bacteriocin and biosurfactant production. Bacterial DNA was extracted, and amplified by PCR method. Results: The 3 isolates from cheese, yoghurt and silage were effective against isolated E.coli and could produce biosurfactants. Phylogenic relationships of the 3 potential candidates were determined comparing the 16Sr DNA gene sequences, they were found to be as 3 isolates of Lactobacillus buchneri, L.brevis and L.kefiri that were effective on the isolated E.coli from environment. Conclusions: It was found that the isolated bacteria produced biosurfactants that had a great potential for different industries.