菌株M降解硝基苯效果研究

Preliminary Study on Degradation of Nnitrobenzene by Strain M

[目的]对菌株M生长条件、对硝基苯的降解效果、耐受性和代谢产物的生物毒性进行研究,为硝基苯废水生物降解提供理论依据。[方法]从受硝基苯污染的土壤中筛选出能以硝基苯为唯一碳源的菌株M,采用锌还原-盐酸萘乙二胺分光光度法测定硝基苯浓度研究不同pH、温度、接种量、硝基苯浓度对硝基苯降解率的影响。[结果]在pH为7,温度30℃,接种量10%(v/v)的最佳条件下,浓度低于500 mg/L的硝基苯12 h内被菌株M完全降解;浓度为600～700 mg/L的硝基苯24 h内被菌株M完全降解;菌株M对硝基苯的最大耐受浓度为900 mg/L;300 mg/L的硝基苯经菌株M降解后的代谢产物的生物毒性在12 h内逐渐降低直至无毒。[结论]菌株M对硝基苯废水具有快速降解效果,可以对降解进行动力学拟合,为实际废水处理提供依据。

[Objective]The study aimed to provide the theoretical basis for biological degradation of nitrobenzene in the wastewater through the research on growing conditions,degradation effects on nitrobenzene,tolerance and biological toxicity of metabolites for the strain M.[Method]The strain M,which could use nitrobenzene as a sole carbon source,was screened from the nitrobenzene-contaminated soil and the degradation concn.of nitrobenzene was determined by Zinc reduction-hydrochloric acid naphthalene ethylenediamine spectrophotometric method so as to study the effects of different pH,temperature,inoculated volume and nitrobenzene concn.on the degradation rate of nitrobenzene.[Result]Under the optimum condition with temperature of 30 ℃,pH of 7 and inoculated volume of M 10%（v/v）,the nitrobenzene within 500 mg/L was completely degraded by the strain M within 12 h and the nitrobenzene at 600-700 mg/L was completely degraded within 24 h.The highest tolerance concn.of nitrobenzene to nitrobenzene was 900 mg/L.After the nitrobenzene at 300 mg/L was degraded by strain M,the biological toxicity of its metabolite was decreased gradually till nontoxic within 12 h.[Conclusion]The strains M had a very fast degradation effects on the nitrobenzene wastewater and could make the dynamics fit for the degradation,which could provided the basis for the practical wastewater treatment.