一株北极海洋细菌及其蛋白酶的生理生化特征研究

从北极海洋环境中筛选分离出一株产胞外碱性蛋白酶的革兰氏阴性杆菌 Ar/ W/ b/ 75°2 5′ N/ 1。该菌能在 7～ 30℃范围内生长 ,并且在 30℃条件下生长良好 ,但不能在 40℃条件下生长。该菌在 0 .5%～ 1 0 % Na Cl的盐浓度范围内能良好生长 ,表现出一定的嗜盐性。葡萄糖、蔗糖及可溶性淀粉等碳源物质可被该菌株利用以供生长之需 ,其中以葡萄糖最佳。氮源物质中 ,蛋白胨是最有利于菌株生长、产酶的有机氮源 ,而 NH4 NO3则是效果最好的无机氮源。对该菌蛋白酶的酶学特性研究表明 :所产胞外蛋白酶占其蛋白酶总量的 75.7%左右 ;蛋白酶反应的最适温度为40℃ ,酶活力在温度不高于 40℃条件下保持稳定 ;该菌蛋白酶具有较宽的 p H活性范围 ,在 p H7～ 1 1均表现出较高酶活力 ,其最适 p H在 8左右

CHARACTERIZATION OF AN ARCTIC MARINE BACTERIUM PRODUCING PROTEASE

WT5BZ]A Gram negative marine bacterium Ar/W/b/75°25′N/1 producing extracellular alkaline protease was isolated in Arctic. The bacterium could grow at the range of temperature from 7 to 30℃, and grew better at 30℃,but it could not grow at 40℃. Keeping certain salinity concentration in medium was necessary for bacterium's growth for its some halophilic character. The bacterium could grow well in medium containing salinity concentration from 0.5% to 10% sodium chloride. Glucose, sucrose and soluble starch could be utilized by the strain, and among them glucose was the optimal carbon source for growth of the bacterium. Peptone was the optimal organic nitrogen source for growth and protease producing of the strain, and ammonium nitrate was the optimal inorganic nitrogen source. About 75.7% of total protease of the strain were extracellular enzyme. Optimal temperature for proteolytic activity was 40℃, and the thermal stability of protease kept stable when temperature wasn't higher than 40℃. Protease of the strain showed high proteolytic activity from pH 7 to pH 11, its optimal pH was 8. [WT5HZ]