Nisin产生菌的筛选及鉴定

Screening and Identification of Nisin-producing Strain

从新鲜牛奶样品中用M17G筛选培养基定向筛选出20株目的菌株。应用琼脂扩散法,以黄色微球菌(Micrococcus flavus)NCBI8166为指示菌对其发酵产物进行效价测定,经反复筛选,获得1株稳定的高产菌株KY08,产Nisin效价为813IU·mL-1。用细菌鉴定系统Vitek-32进行生化特征鉴定,并参照了《伯杰氏细菌学鉴定手册》(第八版),将KY08菌株初步鉴定为乳酸链球菌种的一个亚种。

More than 20 strains were screened by fresh milk samples on M17G culture medium. The antimicrobial activities of their fermentation products were tested by the agar-diffusion method, using Micrococcus flavus NCBI8166 as an indicating strain. One stable and high-yield strain was obtained and named as KY08. Its production was up to 813 IU.mL^-1. According to the results of automated microbiological analysis instrument-Vitek-32 and Berges Bacteriology （the eighth edition）, KY08 was tentatively identified as a subspecies of Streptococcus lactis.