南京农业大学学报2017，Vol.40Issue(4)：655-663,9.DOI:10.7685/jnau.201609042
取代脲类除草剂降解菌鞘氨醇杆菌(Sphingobium sp.)Pu21的分离和鉴定与降解特性
Isolation, identification and biodegradation characteristics of phenylurea herbicide-degrading bacterium Sphingobium sp.Pu21
摘要
Abstract
[Objectives]The aim of this study is to isolate high efficient phenylurea herbicides-degrading bacteria,and provide theoretical foundation and material basis for bioremediation of the pesticide-contaminating soil.[Methods]A bacterial strain designated as strain Pu21,capable of degrading phenylurea-herbicides efficiently,was isolated from activated sludge collected from the wastewater treatment system of a pesticide factory,and then identified according to its phenotype,physiological and biochemical characteristics and the similarity analysis of its 16S rRNA gene sequence.After that,the degradation characteristics and pathway of isoproturon and linturon by Pu21 were studied.[Results]The bacterium Pu21,identified as Sphingobium sp.,could degrade both isoproturon and linuron,which belong to N,N-dimethyl-substituted phenylurea herbicide and N-methoxy-N-methyl-substituted phenylurea herbicide,respectively.This strain could degrade isoproturon and linuron efficiently in the temperature range of 25-35 ℃ and pH value range of 6.0-8.0.The optimum temperature and pH value for degradation were 35 ℃ and 7.0,respectively.The addition of glucose or maltose considerably enhanced the degradation rate of linuron rather than isoproturon.However,the degradation rates of these two herbicides were increased significantly while adding peptone or yeast extract as co-substrate.Strain Pu21 could also degrade other phenylurea herbicides such as diuron,fluometuron,ide,chlorotoluron,metoxuron,monuron,fenuron and monolinuron.Based on the data of HPLC and MS/MS results,we proposed isoprotturon degradation pathway in strain Pu21.In which,isoproturon was degraded by mono-N-demethylation to yield N-(4-isopropylphenyl)-N-methylurea(MDIPU),then MDIPU was transformed to 1-(4-isopropylphenyl) urea (DDIPU) via further N-demethylation,followed by the cleavage of the urea side chain to generate 4-isopropylaniline(4IA).Using the same methods,we also proposed linuron degradation pathway in strain Pu21.That is,the amide hydrolysis of linuron resulted in the generation of intermediate metabolite 3,4-dichloroaniline(3,4-DCA).[Conclusions]Strain Pu21 has excellent degradation ability,broad substrate spectrum and great potential for the bioremediation of pesticide ∑ contaminating soils and wastewater treatment using bioaugmentation technique.关键词
取代脲类除草剂/降解菌/生物降解特性/代谢途径Key words
phenylurea herbicides/degrading-bacteria/biodegradation characteristics/metabolic pathway分类
生物科学引用本文复制引用
谷涛,李永丰,周潮洋,张迹,闫新,李顺鹏..取代脲类除草剂降解菌鞘氨醇杆菌(Sphingobium sp.)Pu21的分离和鉴定与降解特性[J].南京农业大学学报,2017,40(4):655-663,9.基金项目
国家公益性行业(农业)科研专项(201303031) （农业）
国家自然科学基金项目(31501657,31300099) （31501657,31300099）
江苏省农业科技自主创新基金项目[CX(14)5021] （14）
