BACTERIOCINS FROM LAB
KUK, Kurukshetra University, Haryana, India
Lactic acid bacteria (LAB) produce bacteriocins having antimicrobial activity against pathogenic microorganisms causing food spoilage. They are involved in food fermentations and Produce lactic acid as the major metabolic end product of carbohydrate fermentation. Lactic acid and other metabolic products contribute to the organoleptic and textural profile of a given food item. They are generally recognized as safe (GRAS), due to their ubiquitous appearance in food and their contribution to the healthy micro flora of human mucosal surfaces. They are found in milk products and decomposing plants. The genera that comprise the LAB include Lactobacillus, Lactococcus,Leuconostoc, Pediococcus and Streptococcus, as well as Weissella, Vagococcus, Tetragenococcus, Sporolactobacillus, Oenococcus, Enterococcus, Carnobacterium and Aerococcus,; these belong to the order Lactobacillales. They are acid-tolerant, rod/cocci-shaped, normally non-sporulating, Gram-positive, with low-GC content, microaerophilic bacteria. Bacteriocins are similar to Paramecium and Yeast killing factors. They are ecologically, functionally and structurally very diverse biomolecules. A. Gratia called his first discovery a colicine because it killed E. coli. Bacteriocins are proteinaceous compounds produced by bacteria to inhibit the growth of similar or closely related bacterial strains. They were first discovered by A. Gratia in 1925. He was involved in the process of searching for ways to kill bacteria, which also resulted in the development of antibiotics and the discovery of bacteriophage, all within a span of a few years. Applications of bacteriocins are being tested to assess them as narrow-spectrum antibiotics. LAB also produce bacteriocins which are heat-stable ribosomally synthesized antimicrobial peptides. Future perspectives and potential applications of these novel bacteriocins will be discussed during the presentation. The reports of new bacteriocins with unique properties indicate that there is still a lot to learn about peptide antibiotics. The system of fast tracking the discovery of novel bacteriocins, belonging to different classes, and isolated from various sources will also be discussed in detail. These bacteriocins have huge potential as both food preservatives, and as next-generation antibiotics targeting the multiple-drug resistant pathogens. Current updates regarding the structural characterization, mode of antimicrobial action, and biosynthetic mechanisms of various novel bacteriocins will be highlighted during the presentation.Bacteriocins are antimicrobial peptides produced by a large number of bacteria, including lactic acid bacteria, acting against closely related and some spoilage and disease-causing pathogens. Biosafety, biotechnological applications in food and pharmaceutical industries, mode of action, purification techniques and recent classification of bacteriocins as well as recent attempts to generate custom-designed bacteriocins using genetic engineering techniques will be discussed in detail. Consumers are very much aware of the health concerns regarding food additives. Demand for new antibacterial compounds has brought great interest for new technologies able to enhance food microbiological safety. Nisin is one of the bacteriocins which exhibits a wide-spectrum antimicrobial action against many pathogens including Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus. Milk or whey can be supplemented with ex situ produced bacteriocin preparations obtained by fermentation.
All the standard methods have been followed.
Bacteriocins with great potential have been obtained and characterized.
Bacteriocins so obtained have great potential in food and pharmaceutical industry.
Keywords: Lactic acid bacteria, Bacteriocin, Probiotics, Antimicrobial, Peptides, Bacteriocidal
Saharan B. (2016). Bacteriocins from Lab.
Conference Proceedings of IPC2016. Paper presented at the International Scientific Conference on Probiotics and Prebiotics, Budapest (p. 64.). IPC2016