一种产蛋白酶菌的菌种选育及发酵条件研究

Screening of a high yield protease producing strain and studies on its fermentation conditions

一株具有溶解血纤维蛋白活性的菌株 A1,经亚硝基胍和紫外线复合诱变获得一株纤溶活性较高的突变株 C2 2 ,其半成品酶比活力可达到 2 94 7.6 0 u·mg-1蛋白 ,产酶活力为未诱变菌株的 4 .2 3倍。本文对其产酶的最适条件进行了优化 ,结果表明产酶最适培养条件为 :培养基组成 2 .5%豆饼粉 ,0 .1%酵母提取物 ,0 .2 % Na Cl,0 .0 5% Mg SO4 · 7H2 O,0 .0 0 1% Fe SO4 · 7H2 O,用 0 .0 5mol· L-1,p H7.4的磷酸缓冲液配制 ;培养基起始 p H7.0～ 7.5,2 5℃旋转摇床培养 4

A1 strain with fibrinolytic activity was isolated from sea water in Qingdao. After combination treatment with ultraviolet light and MNNG, a mutant C22 producing 2947.60 u·mg -1 protein of fibrinolytic enzyme in culture broth was obtained.Its enzyme activity was 4.23 fold of wild stain A1.The optimum medium for fermentation consisted of 2.5% soy bean cake meal, 0.1% yeast extract,0.2%NaCl,0.05%MgSO 4·7H 2O,0.001%FeSO 4·7H 2O.They were dissolved with 0.05mol·L -1 ,pH7.4 phosphoric buffer.The strain producing maximum fibrnolytic activity after growth at 25℃ for 40h on a rotary shaker.The initial optimum pH was 7.0~7.5.