Revisión: Espectro antimicrobiano,estructura,propiedades y mode de acción de la nisina,una bacteriocina producida por Lactococcus lactis/Review: Antimicrobial spectrum,structure,properties and mode of action of nisin,a bacteriocin produced by Lactococcus lactis

Abstract

Nisin is a 34 amino acid antibacterial peptide produced by certain strains of Lactococcus lactis. This bacteriocin has found wide application as a food preservative owing to its non-toxic nature, its heat stability at acidic pH, its inactivation by proteolytic enzymes in the digestive tract and, especially, to its antimicrobial activity against a broad range of Gram-positive organisms, including food pathogens of concern in food industry such as Clostridium botulinum and Listeria monocytogenes. However, the use of nisin has the limitation that its solubility and stability decrease progressively as the environ mental pH increases. The two natural variants of nisin, named nisin A and nisin Z, are ribosomally synthesized as 57 amino acid precursor peptides which are subjected to further modifications. The mature peptide displays several unusual features, such as the presence of dehydrated amino acids and lanthionine rings. Insertion of the peptide into the cytoplasmic membrane of susceptible cells leads to the formation of pores, dissipating the membrane potential and pH gradients.