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Nisin from Lactococcus lactis fermentation product distill a peptide substances, on the basic body non-toxic , nor to produce cross-resistance with the medical antibiotics , can be degraded in the gut , is a world- recognized safe natural biological food preservatives and antibacterial agents. Has been widely used in more than 50 countries and regions , but China nisin research started late , research mostly also concentrated in Optimization of fermentation conditions , to achieve large-scale production level of the manufacturers are not more than , the limits of nisin in China . This paper to explore penicillin pretreatment concentration , pretreatment time , lysozyme concentration , hydrolysis time , hydrolysis temperature conditions research Lactococcus lactis protoplast formation and regeneration conditions ; by UV mutagenesis protoplasts , agar block method selected bringing out a nisin producing strains , confirmed the strains genetic stability is better after consecutive 5 -generation test ; corn syrup and sugar mash of industrial wastes as raw materials for high-yielding strains of optimization of the medium composition ; reuse 5L four associated fermenter this overproducing strain amplification culture inoculum age, inoculum size, dissolved oxygen , and the initial pH value of nisin titer . With the continuous improvement of people's living standards , the demand and consumption of dairy products, meat products , fruits and vegetables is increasing. The development and use of nisin , can save energy , improve food quality , extend shelf time , so as soon as possible to develop a large number of nisin product of great significance for China 's green food preservative .
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