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Lactic acid bacteria probiotic is widely used in food fermentation industry, it can inhibit or kill pathogens and food spoilage bacteria. In recent years, studies have shown that lactic acid bacteria can secrete to produce one or more antibacterial substances bacteriocin is an efficient, non-toxic, no residue, no drug resistance, etc., has become the focus of the study of food biotechnology corrosion, at the same time is considered to be the most effective antibiotics substitute. Therefore, this article is designed to filter out the high-yielding strains of lactic acid bacteria bacteriocin, and screening strains fermentation medium optimized to get maximum antibacterial activity of bacteriocins. The indicator bacteria E. coli and Staphylococcus aureus, have higher antibacterial activity of lactic acid bacteria screened from a variety of materials, may produce efficient antibacterial activity of lactic acid bacteria sources to explore. Meanwhile, according to the lactic exclusion, the exclusion of hydrogen peroxide and protease testing consolidated speculated that the antibacterial effect of the lactic acid bacterium may be derived from a bacteriocin, 15d bacteria bacteria Quality granulocyte extract using a modified alkaline lysis method, results from the different sources of material Filter 10 higher antimicrobial activity of lactic acid bacteria, which produce bacteriocins, lactic acid bacteria from silage 15d bacteria. There is no natural plasmid, speculated 15d bacteria produce bacteriocins may be coded by the chromosome. 15d strain colony and cell morphology observed specific amplification of the physicochemical characterization and 16SrDNA, and sequence analysis, comparison, the comprehensive identification results to determine 15d bacteria Lactobacillus casei. MRS-based medium 15d fermentation medium optimization using RSM method. Using Plackett-Burman experimental design screening significant factor to determine the affect bacteriocin produced ingredients, recycling RSM method to optimize the medium. Optimization results show that the medium containing glucose 33.77g / L, and sodium acetate, 9.56 g / L, Tween 0.44 mL / L, citric acid the triammonium 1.42 g / L, peptone 15 g / L, meat extract of 10 g / L, yeast extract 5 g / L, dipotassium hydrogen phosphate, 2 g / L, magnesium sulfate 0.2 g / L, sulfuric acid Meng 0.25 g / L, and a pH of 5.9, 15d bacteria's ability to secrete bacteriocins best. Screened from silage, Lactobacillus casei out of a production of bacteriocins, bacteriocin produced by inhibition of E. coli, unlike similar domestic research, this characteristic of bacteria in chicken feed and add applications to lay a paper foundation piglet feed.
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