Nisin产生菌株的筛选及产物初步探究与鉴定

Screening of Nisin-producing Strains and Preliminary Exploration and Identification of Their Products

通过改良GM17培养基,以蔗糖为唯一碳源,加入0.004%溴甲酚紫和1500IU/mg的Nisin标准品,从新鲜的白菜叶片表面筛选到具有Nisin耐受性、产酸、革兰氏阳性的球形菌株,经牛津杯法抑菌圈试验和16SrDNA初步鉴定为乳酸乳球菌(Lactococcus lactis),命名为L-217;通过对该菌株发酵液中的抑菌物质进行稳定性验证,发现其在低pH及90℃水浴条件下均具有良好的稳定性;采用大孔吸附树脂对发酵液中的抑菌物质进行吸附并浓缩纯化,通过高效液相色谱法(HPLC)将纯化液与Nisin标准品进行对比,确定抑菌物质为Nisin。

A spherical strain with Nisin tolerance,acid-producing ability and Gram-positive is screened from the surface of fresh Chinese cabbage leaves by adding 0.004% bromocresol purple and 1500 IU/mg Nisin standard sample with sucrose as the sole carbon source.The strain is identified as Lactococcus lactis by Oxford cup method and 16 SrDNA preliminary identification,is named as L-217.The stability of the bacteriostatic substances in the fermentation broth of the strain is verified,and it is found that the bacteriostatic substances have good stability under low pH value and 90℃ water bath conditions.The bacteriostatic substances in the fermentation broth are adsorbed,concentrated and purified by macroporous resin,the purified liquid is compared with the Nisin standard sample by high pertormance liquid chromatography(HPLC),and the antimicrobial substance is identified as Nisin.