乳链菌肽高产菌株的选育及其基因定位

THE SCREENING OF HIGH-YIELD NISIN PRODUCING STRAINS AND LOCALIZATION OF PRECURSOR NISIN GENE

以乳酸乳酸球菌7962为原始菌株,用紫外线、LiCl、(60)~Co及8-MOP+NUV等多种理化诱变剂对其进行诱变处理,获得一株乳链菌肽高产突变株AL2。其效价稳定在2300～2500Iu/ml。经DNA杂交证实,编码乳链菌肽的前体基因位于染色体上,其遗传性状是稳定的。毒理试验表明AL2及其产物属于实际无毒类物质。

A mutant strain AL2 with high yield of nisin was obtained from Lacto-coccus lactis 7962 by treatment with physical and chemical factors. The nisin activities of fermentation medium were 2300-2500 IU/ml. LD50 test results indicated that AL2 strain and its product (nisin) are nontoxic. Hybridization experiments suggested that the presence of precursor nisin gene is on the chromosome.