The Study Of Bacteriocin Produced By Lactobacillus Plantarum ZJ217

The preservatives is one of the most important additives in the food industry. The preservatives is an effective way to prevent food spoilage. At present, China is extensive use of chemical preservatives, which may cause food safety risks. Nisin is used widely as one of a natural preservative, but it can inhibit G+bacteria only and cannot inhibit G-bacteria, yeast and fungus. Plantaricin, produced by Lactobacillus plantarum, has a high resistance of high temperature and acid. Plantaricin, which can be biodegradable in body, was considered safe and has a strong antibacterial activity.In the present paper, we isolated a bacteriocin-producing strain from milk. Then, the primary characteristics of plantaricin ZJ217, a novel bacteriocin with a broad inhibitory spectrum produced by Lactobacillus plantarum ZJ217, were analyzed. These results were described as followes: 1. We isolated a bacteriocin-producing strain from milk. Through the observation of morphological, physiological and biochemical analysis, the identify of16S rRNA, we found that the LAB was a Lactobacillus plantarum, and named Lactobacillus plantarum ZJ217, the bacteriocin named plantaricin ZJ217.2. After, hydrophobic interaction, ion exchange chromatography, gel permeation chromatography and reverse-phase HPLC purified, the plantaricin ZJ217was separation and collected by a single vitality peak. This indicates that the plantaricin ZJ217has reached a single component. fold and the yield of plantaricin ZJ217were301and1.76%respectively. The mass spectrometry of plantaricin ZJ217showed a molecular weight of2632.537Da. Edman method for sequencing of the N-terminal amino acid sequence of plantaricin ZJ217, the sequence is NLPQLTQTLVVAPPF.3. Plantaricin ZJ217had a better biological characterization. It was acid and alkalitolerant in the conditions between pH2and8. And it was stable under high temperature as well. The residual activity was beyond80%when treated at121℃for30min. It was completely inactivated by pepsin, papainase and trypsin. Meanwhile, it was partial inactivated by protease K. Lactobacillus plantarum ZJ217began to produce plantaricin ZJ217at the logarithmic phase at37℃. Its yield reached the highest value at the stationary phase during the fermentation process. Then the production of plantaricin ZJ217kept stable.4. Plantaricin ZJ217belonged to the broad spectrum barteriocin, including the gram-negative bacteria and gram-positive bacteria, such as P. putida, B. subtilis, L. monocytogenes, S.flexneri, S. citreus, E. coli, etc. Through the restore growth methods by observed indicator strain, we found the mode of action of plantaricin ZJ217is sterilization. By measuring the indicator bacteria intracellular K+and leakage of nuclear substances, the plantaricin ZJ217can bacterial indicator bacteria in a very short time.