中文摘要：

采用硫酸铵盐析法及乙醇沉淀法对海洋枯草芽孢杆菌纤溶酶的纯化效果进行比较研究,得到的最佳纯化方案为：取一定体积的纤溶酶发酵液进行预处理,再进行分段盐析及分级沉淀,在分段盐析中,30％和70％饱和度的硫酸铵分别用于去除杂蛋白和沉淀纤溶酶,最后进行碱处理及超滤除盐;在分级沉淀中,最佳乙醇沉淀时间为1.5h,去除杂蛋白和沉淀纤溶酶的乙醇体积比分别为25％和165％,最后将两种方法得到的粗提液进行冷冻干燥,硫酸铵法的酶活回收率为83.52％,纯化倍数为1.42,冻干粉得率为4.812 g/L,单位酶活为76 755.82IU/g;乙醇纯沉淀法的酶活回收率为89.7％,纯化倍数为1.72,冻干粉得率为7.611 g/L,单位酶活为137 190.57 IU/g,该结果表明乙醇沉淀法对纤溶酶的粗提效果要优于硫酸铵盐析法.

英文摘要：

In this paper,ammonium sulfate precipitation and ethanol precipitation method were applied to investigate the purification effect of fibrinolytic enzyme produced by marine Bacillus subtilis,and the optimal purification conditions were determined.Firstly,the fermentation broth of fibrinolytic enzyme was pretreated,and then segmented salting-out and fractional precipitation were conducted,some miscellaneous protein was removed by 30％ ammonium sulfate in salting-out experiment,and fibrinolytic enzyme was precipitated by 70％ ammonium sulfate,finally some alkali was added into the fibrinolytic enzyme solution,and fibrinolytic enzyme was desalted by ultrafiltration.In fractional precipitation,the optimal ethanol precipitation time was 1.5 h,and the ethanol volume for removal miscellaneous protein and precipitate crude enzyme were 25％ and 165％,respectively.Finally the crude extract was treated with freezing-drying.Results showed that the recovery rate of fibrinolytic enzyme was 83.52％ and purification times 1.42 after ammonium sulfate precipitation,yet the recovery rate of fibrinolytic enzyme was 89.7％ and purification times 1.72 after ethanol precipitation.In addition,the freezing-drying powder yield and unit of enzyme activity of ammonium sulfate precipitation was 4.812 g/L and 76 755.82 IU/g,but that of ethanol precipitation was 7.611 g/L and 137 190.57 IU/g,respectively.The results showed that ethanol precipitation was better than ammonium sulfate precipitation in crude exacting of fibrinolytic enzyme.