Bacteriocins: Promising Natural Antimicrobials

Bacteriocins are multifunctional, ribosomally produced proteinaceous substances with pronounced antimicrobial activities at certain concentrations25. They are proteinaceous toxins produced by bacteria and certain members of archaea to inhibit the growth of similar or closely related bacterial strains15. These molecules have antimicrobial activity against pathogenic and deteriorating bacteria, justifying their biotechnological potential. If the bacteriocins produced by a bacterium inhibit other bacteria belonging to the same species, they are generally considered to be narrow spectrum bacteriocins. In contrast, if they inhibit bacteria belonging to another genus, they are considered as broad spectrum bacteriocins. Bacteriocins produced by Lactic Acid Bacteria (LAB) are of particular importance, because these bacteria received Generally Recognized as Safe (GRAS) status by the American Food and Drug Administration (FDA)122. Thus, nisin produced by Lactococcus lactis was the first bacteriocin to gain widespread commercial application. Since then, a large number of bacteriocins from a diverse group of bacterial strains have been identified. Bacteriocins have many positive properties that have made them particularly interesting for various applications. LAB bacteriocins are inherently tolerant of high thermal stress and are known for their activities over a wide pH range. These antimicrobial peptides are also colorless, odorless and tasteless, which further improve their potential usability. They are also easily degraded by proteolytic enzymes due to their proteinaceous nature. Consequently, bacteriocin fragments do not live long in the human body or in the environment, which minimizes the chance of target strains interacting with degraded antibiotic fragments.