Comparative studies of class IIa bacteriocins of lactic acid bacteria (original) (raw)
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Determination of Antibacterial Activity of Bacteriocins of Lactic Acid Producing Bacteria
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Received: 2013-01-30 Revised: 2013-02-27 Accepted: 2013-02-28 This study was conducted to explore the potential of bacteriocins, produced by lactic acid producing bacteria, against Staphylococcus aureus, Eneterococcus fecalis and Escherichia coli. Different lactic acid producing bacteria viz. Lactobacillus fermentum, Lactobacillus acidophilus and Lactobacillus rhamnosus were isolated from milk, milk products of dairy animals and intestinal contents of healthy broiler chicken. These isolates were identified morphologically and biochemically by conventional methods. Bacteriocins were obtained from these bacteria, by precipitation method. Antibacterial activity of bacteriocins was determined by disk diffusion method. Isolated bacteriocin showed the inhibitory activity against Staphylococcus aureus and Enterococcus feacalis but showed very poor inhibitory activity (2mm) against Eschrechia coli. The result of this study showed that bacteriocins are quite useful against commonly known foo...
Bacteriocins of Lactic Acid Bacteria and their Industrial Application
Current Topics in Lactic Acid Bacteria and Probiotics, 2021
Lactic acid bacteria produce different types of inhibitory compound that have a bactericidal effect. The inhibitory compounds produced include metabolic end products, bacteriocins that are antimicrobial peptides with antibiotic effect, hydrogen peroxides and numerous organic acids depending on their fermentation pathway. The inhibitory activity by bacteriocins produced by lactic acid bacteria is diverse, comprising of strains capable of inhibiting different types of Gram-positive microorganisms to those that affect only organism of close general. With the growing concern over the spread of antibiotic-resistant microorganisms and the possibility of current therapies becoming inefficient, it is imperative to find antibiotics alternatives. In food preservation, naturally occurring peptides with antimicrobial activity are favoured over chemical preservatives a more reason why there should be a holistic approach to taking advantage of bacteriocinogenic bacteria in medicine and food industry. This review focuses on the application of bacteriocin in food preservation, food industry, livestock and medicine.
Bacteriocins Produced by Lactic Acid Bacteria A Review Article
http://dx.doi.org/10.1016/j.apcbee.2012.06.010 ICBFS 3rd International Conference on Biotechnology and Food Science
A great number of Gram (+) and Gram negative (-) bacteria produce during their growth, substances of protein structure (either proteins or polypeptides) possessing antimicrobial activities, called bacteriocins. Although bacteriocins could be categorized as antibiotics, they are not. The major difference between bacteriocins and antibiotics is that bacteriocins restrict their activity to strains of species related to the producing species and particularly to strains of the same species, antibiotics on the other hand have a wider activity spectrum and even if their activity is restricted this does not show any preferential effect on closely related strains. In addition, bacteriocins are ribosomally synthesized and produced during the primary phase of growth, though antibiotics are usually secondary metabolites. Among the Gram (+) bacteria, lactic acid bacteria (LAB) especially, Lactobacilli have gained particular attention nowadays, due to the production of bacteriocins. These substances can be applied in the food industry as natural preservatives. The use of LAB and of their metabolic products is generally considered as safe (GRAS, Grade One). The application of the produced antimicrobial compounds as a natural barrier against pathogens and food spoilage caused by bacterial agents has been proven to be efficient. Nisin is the only bacteriocin that has been officially employed in the food industry and its use has been approved worldwide. Bacteriocins can be applied on a purified or on a crude form or through the use of a product previously fermented with a bacteriocin producing strain as an ingredient in food processing or incorporated through a bacteriocin producing strain (starter culture). Keywords: Lactic acid bacteria, Lactobacilli, Bacteriocins, Nisin, Plantaricins, Lantibiotics
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 10 6 CFU/ml, B884 – 1.0 10 8 CFU/ml, B2455 – 1.0 10 7 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