1株乳酸链球菌素产生菌的筛选鉴定及其抑菌特性的研究

从白菜叶上分离得到21株对乳酸链球菌素(Nisin)有抗性的乳酸菌株,采用杯碟法从中筛选得到抑菌活性较强的菌株T0625,经鉴定该菌株为乳酸乳球菌乳酸亚种(Lactococcus lactis subsp.Lactis)。经测定,发酵液经加热处理,在低pH条件下能够保持较好的抑菌活性,对革兰氏阳性细菌具有明显的抑制作用,但对革兰氏阴性细菌、酵母菌和霉菌不表现抑制作用。研究还证实,T0625的发酵产物的抑菌活性不受胃蛋白酶和胰蛋白酶的影响。经提取纯化,确定抑菌物质为乳酸链球菌素。

Screening and Identification of a Nisin-producing Strain and Studying on Its Antibacterial Characteristics

21 strains of Lactic acid bacteria isolated from the leaf of Chinese cabbage had resistance to Nisin.By Oxford plate assay system,one strain with strong antibacterial activity designated as T0625 was screened from them.The strain of T0625 was finally identified as Lactococcus lactis subsp.Lactis.Based on the result of measurement,the antibacterial activity of the fermented broth was thermo-stable under the low pH,and insensitive to pepsin and trypsin as well.The fermented broth showed inhibition to some gram-positive bacteria,in contrast,little inhibition activity to gram-negative bacteria,yeast or mould.By extraction and purification,the antibacterial extract sample was determined as Nisin.