Bacteriocin production by Lactobacillus spp. And study on it's antimicrobial activity against some pathogenic microorganisms

Bacteriocins are antimicrobial proteins which prevent the growth of sensitive strains. The aim of study is to produce antimicrobial products using the lactic acid bacteria separated from low fat yogurt and survey on their antimicrobial activity. At the first bactobacillus separated from two kinds of pasteurized yogurt of Gilan and then its effect on E.coli and a staphylococcus aureus was studied by disc and gel diffusion methods. Also effect of different physicochemical factors on bacteriocin production was evaluated، using Taguchi methodology. The greatest zone diameter and the highest rate of production and E.coli (17 mm). This diameter was observed in PH 5، inoculation size 20%, temperature 25oC, Glucose and yeast extract as the carbon and nitrogen sources. The result analysis of varians showed that carbon and nitrogen type had significant product. The results in optimized MRS broth medium show that the best bacteriocin production in the optimized environment was 70% greater and it could be prev the bacterial growth property .