一株产碱杆菌DN25中降氰酶的提取和特性研究

Extraction of Cyanide-degrading Enzyme from Alcaligenes sp. DN25 Strain

从实验室自行保藏的一株高效降氰菌株——产碱杆菌Alcaligenes sp.DN25中提取降氰酶,并研究其降解特性。通过分别测定胞内酶、胞外酶和细胞碎片对氰化物的降解率,初步判断该菌株降氰酶主要分布在细胞内。所提取的降氰酶具有较好的保存稳定性和pH稳定性,降解最适条件为温度35℃、pH7.0,并测得该降氰酶的米氏常数Km和最大反应速率分别为267.8mg/L和6.71mg/(L·min)。检测出该酶降解氰化物的产物之一为NH3,降解完全;尿素对酶活有抑制作用,初步可断定此酶中存在氰水合酶。

This paper relates to the extraction of cyanide-degrading enzyme from Alcaligenes sp. DN25 Strain in the lab and the experimental study of its property. Result showed that endoenzyme of strain DN25 played a main role in degrading cyanide by comparing the cyanide degradation rates of endoenzyme, ectoenzyme and cell residue respectively and that NH3 was the end product of cyanide degradation. The phenomenon of inhibition of urea on enzyme activity can be attributed to the existence of cyanide hydratase in crude enzyme extracted from Alcaligenes sp. DN25 Strain.