摘要
研究了从高效降解细菌HB-5（Arthrobacter）中提取的降解酶的分离条件及酶对莠去津的降解性能．研究证明，对莠去津的降解主要是胞内酶在起作用．从高效降解菌HB-5中提取到的降解酶。在不含有莠去津的培养基中连续转接7次，会逐渐丧失对莠去津的降解代谢活性，由此判断该降解酶不是组成酶，而是诱导酶．以牛血清白蛋白为标准蛋白测得粗提酶中可溶性蛋白含量为0．65mg·mL^-1；在pH8．0～9．5之间，酶活力均能保持在最高酶活力的89％以上，该酶降解莠去津的最适pH为8．5；在25～45℃的温度范围内能保持较好的降解活性，最适温度为35℃；进一步研究发现，该酶具有较好的热稳定性和pH稳定性，暴露在温度30—40％，pH6．0—9．0的条件下2h仍能保持较高的酶活力；该酶与底物莠去津结合力强，对莠去津具有较好的降解效果，其米氏常数Km为0．7034mmol·L^-1，最大降解速率为0．1863μmol·mg^-1·min^-1．
Degradative characteristics of atrazine were determined using the crude enzyme extracted from an isolated strain HB-5, which had been identified as Arthrobacter sp.. The crude enzyme, which was an intracelluar one, would loss its most activity when the strain was continuously transferred for 7 times under the condition of non-inducement. These results showed that this enzyme was also an inducible one. The concentration of soluble protein of the crude enzyme was 0.65 mg·mL^-1 , determined with Albumin （ bovine serum） as standard. The crude enzyme showed comparatively greatest enzymatic activity at pH 8.5, high activity ranging pH from 8.0 to 9.5. The crude enzyme activity had optimum temperature of 35℃ for enzymatic degradation of atrazine, which was still over 89% of the maximal activity within temperature ranging from 25℃ to 45 ℃. Additional experimental evidence revealed that the enzyme had some extent stability for temperature and pH. The Km value and the maximal enzymatic degradation rate for atrazine were 0.7034 mmol·L^-1 and 0.1863μmol·mg^-1·min^-1 , respectively.
出处
《环境科学学报》
CAS
CSCD
北大核心
2006年第4期579-583,共5页
Acta Scientiae Circumstantiae
基金
国家自然科学基金(No.20477022)
山东省优秀中青年科学家科研奖励基金(03BS123)~~
