Foods and Raw Materials (Jun 2017)
DETERMINATION OF THE INTENSITY OF BACTERIOCIN PRODUCTION BY STRAINS OF LACTIC ACID BACTERIA AND THEIR EFFECTIVENESS
Abstract
The study of bacteriocins is one of the most relevant areas of research. This is due to the increase in the number of pathogenic microorganisms resistant to antibiotics. The bacteriocins of lactic acid bacteria have the most common application because of their safety in use. To assess the antimicrobial potential of bacteriocins of lactic acid bacteria and the possibilities for their further use, this study deals with the intensity of bacteriocin production by strains of lactic acid bacteria, the minimal inhibitory concentration of bacteriocins produced by these strains with respect to E. coli В-6954, as well as the antimicrobial activity of the produced bacteriocins with respect to some strains of pathogenic microorganisms. This work was carried out on the basis of the Kemerovo Technological Institute of Food Industry (Russia). The study objects were strains of microorganisms Lactobacillus delbrueckii B2455, Lactobacillus paracasei B2430, Lactobacillus plantarum B884. Biomass concentration was determined by spectrophotometric method. Study of antimicrobial activity in relation to a number of pathogenic strains was carried out in a culture fluid by optical density, and also by a disk-diffusion test. As a result, the maximum productivity value, characterizing the intensity of bacteriocin production, was observed for strain B884. However, the quality of bacteriocin (antimicrobial activity relative to the E. coli strain) with a lower productivity is higher for strain B2430. The minimum inhibitory concentration for the strains studied was: B2430 - 1.0 106 CFU/ml, B884 -1.0 108 CFU/ml, B2455 - 1.0 107 CFU/ml. The best indicator of the minimum inhibitory concentration was observed for strain B2430. Thus the strain B2430 had the greatest antimicrobial activity, it had an inhibitory effect on 12 test cultures: Escherichia coli, Alcaligenes faecalis, Candida albicans, Pseudomonas libanensis, Staphylococcus warneri, Erwinia aphidicola, Microbacterium foliorum, Bacillus licheniformis, Serratia plymuthica, Erwinia aphidicola, Bacillus endophyticus, Leuconostoc mesenteroides. Thus, among the test Lactobacillus strains, the strain of Lactobacillus paracasei B2430 is promising for further study.
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