Depending on their structural characteristics, LAB bacteriocins have been classified by Klaenhammer into three main groups : class I is small peptides called lantibiotics, which contains post-translationally modified amino acid residues, such as lanthionine and 3-methyllanthionine; class II is small, heatstable, nonmodified and membrane-active peptides; and class III is large and heat-labile peptides. Most bacteriocins belong to class II, which are divided into four groups, namely class IIa, IIb, IIc, and IId. Nisin is the most typical Salvianolic-acid-B bacteriocin and is used as a food preservative worldwide. However, the application of nisin is limited because it exhibits activity against Lithium citrate Gram-positive bacteria. More than 20 plantaricins have been found, and a number of plantaricins have been purified, such as plantaricin JK, plantaricin 1.25, plantaricin NC8, Plantaricin C or plantaricin PASM1. Some plantaricins, such as plantaricin PASM1 and plantaricin 1.25, show a narrow antibacterial spectrum, exhibiting antibacterial activity against bacteria closely relate to the producer microorganism such as lactobacillus strains, similar to many bacteriocins. Plantaricin C, plantaricin JK and plantaricin NC8, like nisin, appear to inhibit some Gram-positive bacteria, such as Lactobacillus sake, Enterococcus faecalis, and Bacillus subtilis, but have no activity against Gram-negative bacteria. Therefore, more broad-spectrum antimicrobial bacteriocins are desired. We screened LAB strains to obtain new bacteriocins that exhibited antibacterial activity not only against Gram-positive bacteria but also against Gram-negative bacteria. We have isolated more than 150 LAB strains from 13 varieties of fermented mustards obtained from supermarkets in China. A LAB strain known as ZJ5, 
which produced bacteriocins, was obtained. Here, the identification, purification, and characterization bacteriocin of the strain ZJ5 is described. In addition, the gene encoding the bacteriocin was cloned and sequenced. In this study, we describe the purification and characterization of a new bacteriocin produced by an environmental isolate strain LAB L. Plantarum ZJ5. Plantaricin ZJ5 shows stability under heating and acidic conditions. However, the peptide demonstrated reduced activity under alkaline conditions. Being proteinaceous in nature, the complete inactivation or significant reduction in the antimicrobial properties of purified plantaricin was observed after treatment with pepsin and proteinase K, but the same was not observed with lipase or aamylase treatment. Most plantaricins appear to inhibit some Gram-positive bacteria, exhibiting antibacterial activity against bacteria closely related to the producer microorganism and have no activities against Gram-negative bacteria. Plantaricin ZJ5 not only has high activity against Gram-positive bacteria, but also has strong activity against Gram-negative bacteria, such as Escherichia coli and Salmonella spp. PZJ5 exhibited activity over a wide range of pH, heat, and bactericidal antimicrobial spectrums, signifying that plantaricin ZJ5 could preserve its structure and bactericidal functions even under extreme conditions, which is an important property in view of its potential use as a biopreservative in foods. Plantaricin ZJ5 was purified from the culture supernatant of L. Plantarum ZJ5 using a four-step purification procedure. Because bacteriocin peptides share many common properties, a purification strategy used by several groups could be applied, such that for plantaricin S and NC8.