摘要
目的:研究除铬优势菌Bacillus cereus Cr2的亚硝酸还原酶(nitrite reductase,NiR)产生情况,以及在Cr(Ⅵ)去除中的作用。方法:通过液体发酵培养和超声破碎的方法获得NiR粗酶液,采用改良的格里斯染色法比较了不同培养温度、pH值、Cr(Ⅵ)诱导浓度及磁场对NiR酶活性的影响,获得最佳产酶条件,进而研究NiR酶活与除铬优势菌去除Cr(Ⅵ)效率之间的关系。结果:细菌产酶的最佳条件是:温度为37℃,pH为6.5,Cr(Ⅵ)诱导浓度为80 mg/L,外加15 mT磁场,酶活力达到30 U/mL,培养体系中的Cr(Ⅵ)诱导浓度低于120 mg/L时不抑制酶活力,此时,NiR酶对Cr(Ⅵ)的去除率比Bacillus cereus Cr2提高10%以上(P<0.05)。结论:NiR酶的存在是Bacillus cereus Cr2除Cr(Ⅵ)的机理。
Objective ：The production condition of the nitrite reductase （NiR） by Bacillus cereus Cr2 and the function of NiR in Cr（ VI ） -removal were studied. Method ：Bacillus cereus Cr2 which was a predominated strains to remove Cr（ VI ）. By fermentation and uhrasonica- tion method got the NiR enzyme. This paper explored four factors impact on enzyme activities by improved griess dyeing, they were the temperature,pH, Cr（ VI ） induced concentration and magnetic field. The relationship between the NiR and the Cr（ VI ） removal rate at the optimal conditions of producing NiR were found. Result：The optimal conditions of NiR collection was that the temperature was 37℃, the pH was 6. 5, the Cr（ VI ） induced concentration was 80 mg/L, and the magnetic field intensity was 15 mT. The NiR enzyme activity reached to 30 U/mL There was no restrain of the enzyme activity when the induced concentration of Cr（ VI ） was lower than 120 mg/L. In the meantime, NiR could improve the Cr （ VI ） - removal rate upper 10% effectively （ P 〈 0. 05 ）. Conclusion： The Cr （ VI ） - removal mechanism of Bacillus cereus Cr2 was the exist of NiR.
出处
《生物技术》
CAS
CSCD
北大核心
2013年第4期75-78,共4页
Biotechnology
基金
国家自然科学基金项目("稳恒弱磁场促进优势菌界面铬(Ⅵ)迁移的机理研究"
No.40801194)资助~~
