海产品中蛋白酶产生菌的选育及产酶条件研究

STUDIES ON THE SCREENING OF PROTEASE-EXCRETED STRAINS FROM SEA FOOD AND ITS FLASK CULTURE CONDITIONS

从海产品虾和蟹中分离出蛋白酶产生菌共37株 ,其中YM007菌株蛋白酶生产活力较高 ,为194.6U/mL。以YM007为出发菌株 ,通过物理和化学方法复合诱变 ,获得了YM079号菌株。对其产酶条件的研究结果表明 :它的最适产酶温度为35℃ ,最适生长pH为7.0 ,经过190r/min摇床培养36～40h,其产酶活力为240U/mL,比出发菌株的产酶活力提高了22%。该菌株经发酵的粗酶液最适作用pH为7.0,最适作用温度是45℃ 。

37protease-excreted bacteria stains were isolated from the sea food crab and shrimp,among of them,YM007strain had higher excreted protease activity,that was194.6U/mL.A mutant strain named YM079was obtained from AS007through multiple mutagenesis(Ultraviolet and DES).Then the several factors influencing the protease production were investigated by flask culture.The results showed that the opti-mum temperature and pH were35℃and7.0respectively.In above conditions,the proteaseˉexcreted acˉtivity was240U/mL after190r/min liquid culture for36～40h.Comparing with YM007,the activity of YM079increased20%.The optimum temperature of the protease was35～45℃,and the optimum pH was6.5～8.0.It belonged to neutral protease.