摘要
旨在获得可高效降解敌草隆的土壤微生物,系统阐明菌株降解特性、敌草隆代谢途径并探索菌株的实际应用潜能。通过唯一碳源法进行富集、驯化和分离获得可降解敌草隆的土壤微生物,通过单因素试验研究菌株的环境的适应性,通过代谢中间产物的质谱分析推测菌株降解敌草隆的代谢途径,通过模拟原位土壤修复探索菌株的实际应用潜能。从长期使用敌草隆的棉田分离获得一株可高效降解敌草隆的细菌LX-C-06。形态学、生理生化特征与16S rRNA基因分析表明菌株LX-C-06为木糖氧化无色杆菌(Achromobacter xylosoxidans)。单因素试验结果表明菌株LX-C-06降解敌草隆的最适温度和pH分别为30℃和pH 7.0;菌株LX-C-06对盐离子浓度具有较高耐受能力,当NaCl浓度为1%、3%和5%时,120 h内对50 mg/L敌草隆降解率分别为100%、100%和87.8%;菌株LX-C-06对较高浓度敌草隆也表现出良好的降解能力,当敌草隆浓度≤400 mg/L时,菌株LX-C-06在120 h对敌草隆的降解率均为100%,当敌草隆浓度升高至600 mg/L时,菌株LX-C-06在120 h对敌草隆的降解率为92.1%。基于代谢中间产物分析推测菌株LX-C-06通过酯键水解将敌草隆转化为3,4-二氯苯胺,并进一步通过脱氨、羟基化、开环等,最终生成琥珀酸被生物体所利用。菌株LX-C-06在30 d内对土壤中50 mg/kg的敌草隆最高降解效率为90.7%。敌草隆降解菌LX-C-06为木糖氧化无色杆菌,该菌对环境温度、pH、盐离子浓度均具有较好的耐受能力,通过酯键水解、脱氨、羟基化、开环等步骤实现敌草隆的转化与利用,菌株同时表现出良好的应用潜能。
This work is designed to obtain soil microorganisms that can efficiently degrade diuron,to systematically elucidate the characteristics of this strain degrading diuron and its metabolic pathway,and to explore the practical application potential of the isolated strain.Sole carbon source method was applied for enrichment,domestication and isolation of diuron-degrading soil microbes.Then single factor test was used to investigate the strain’s environmental adaptability.Further mass spectrometry analysis of metabolic intermediates was to deduce the metabolic pathway of the strain degrading diuron.And simulating in situ soil remediation was to investigate the application potential of the isolated strain in soil remediation.As results,one bacterial strain LX-C-06 that effectively degraded diuron was isolated from cotton fields with long-time diuron application.The strain LX-C-06 was identified as Achromobacter xylosoxidans via morphological,physiological and biochemical characteristics and 16S rRNA gene analysis.The results of single factor tests indicated that the optimal temperature and pH for diuron degradation by strain LX-C-06 were 30℃ and 7.0,respectively.The strain LX-C-06 showed high tolerance to NaCl concentration.The degradation rates of 50 mg/L diuron within 120 h were 100%,100% and 87.8% when NaCl concentration was 1%,3% and 5%,respectively.The strain LX-C-06 also showed good degradation ability towards high concentration of diuron,and the degradation rate of the strain LX-C-06 to diuron was above 100% within 120 h when diuron concentration was ≤ 400 mg/L.The degradation rate of diuron was 92.1% within 120 h when diuron concentration increased to 600 mg/L.Based on the identification of metabolic intermediates,it was speculated that the strain LX-C-06 transformed diuron into 3,4-dichloroaniline via hydrolyzing ester bond.And 3,4-dichloroaniline was further transformed into succinic acid by deamination,hydroxylation and ring-cleavage.Within 30 d,the maximum degradation rate of 50 mg/kg diuron in soil was 90.7% with bioaugmentation of the strain LX-C-06.In conclusion,the strain LX-C-06 is identified as Achromobacter xylosoxidans that efficiently degrades diuron.The strain LX-C-06 demonstrates tolerance to environmental temperature,pH,and salinity concentration.The strain LX-C-06 transforms and utilizes diuron by hydrolyzing ester bond,deamination,hydroxylation,ring-cleavage,etc.The strain LX-C-06 also shows promising application potential.
作者
岳丽晓
李登云
张晶晶
仝雷
YUE Li-xiao;LI Deng-yun;ZHANG Jing-jing;TONG Lei(Zhengzhou Institute of Industrial Technology,Zhengzhou 451100)
出处
《生物技术通报》
CAS
CSCD
北大核心
2020年第6期110-119,共10页
Biotechnology Bulletin
基金
河南省十三五规划课题(JKGHYB-0560)
河南省教育厅重点项目(192102310416)。