产碱性蛋白酶芽孢杆菌的鉴定

Identification of a Bacillus strain producing alkaline protease

摘要:

通过测量比较在碱性蛋白平板上产生的蛋白水解圈直径, 从土壤中筛选到一株高产蛋白酶菌株Bacillus sp. HFBL0079, 根据生理生化特性、16S rDNA 序列, 鉴定为B. amyloliquefaciens。其最适培养温度为35 °C?37 °C, 最适生长pH 8.0, 在特定培养条件下16 h 达到稳定期, 菌体生长和蛋白酶合成同步进行。以大豆分离蛋白为氮源时发酵液具有最高酶活。发酵液在pH 10 时具有最高酶活, 表明为碱性蛋白酶。该菌株产生的碱性蛋白酶可水解多种天然蛋白质, 对胶原蛋白水解度高于其他蛋白质, 对羽毛角蛋白也有一定水解能力, 提示该酶具有一定新颖性。

Abstract:

A protease producing spore-forming strain named HFBL0079 was islated from soil by measuring clearing zone in alkaline casein plate. Bacillus sp. HFBL0079 was identified as B. amyloliquefaciens by phenotypic properties and 16S rDNA sequence. Its optimal growth temperature was 35 °C?37 °C and initial pH was 8.0. Protease activity increased quickly in log phase in accord with biomass and was steady in stationary phase, the maximal value was found in 16 hour. The highest protease activity was found when nitrogen source was soy protein isolate. The protease was alkaline protease because the highest activity was shown in pH 10. The alkaline protease was shown activity to multi substrate, the highest hydrolysis degree was found in collagen (42.3%) more than casein, oval bumin, BSA, and the hydrolysis degree of keratin was 15.3%, these results indicated the alkaline protease had some novel properties.