敌草隆降解菌SL-6的筛选鉴定及降解条件优化

Screening and identification of diuron-degrading strain SL-6 and optimization of degradation conditions

【目的】明确筛选分离得到的敌草隆降解菌株SL-6生物学分类地位,并优化其降解条件,为降解敌草隆提供新的途径。【方法】采用富集培养法从棉田中分离敌草隆降解菌SL-6,并通过16S rDNA及nrdA基因序列分析结合形态学、生理生化特征对其进行鉴定;运用HPLC法检测SL-6菌株对敌草隆的降解效果,研究该菌株在不同敌草隆初始质量浓度、接菌量、蔗糖含量、pH及温度条件下的降解能力并优化降解条件。【结果】从棉田土壤中分离得到7株菌株,其中,无色杆菌属Achromobacter菌株SL-6、SL-7和SL-9对敌草隆的降解效果好且消解动态符合消解动力学方程;木糖氧化无色杆菌A.Xylosoxidans SL-6降解效果最佳,第15天的降解率为94.6%。在敌草隆初始质量浓度为200 mg/L、接菌量为15%(φ)、不外加碳源、pH为8.0以及温度为30℃时,处理5 d后降解率达93.1%。【结论】SL-6菌株能够高效降解敌草隆,可作为新的菌株资源,为进一步研究微生物降解敌草隆奠定基础。

【Objective】This study was aimed to clarify the biological classification of the diuron-degrading strain SL-6 obtained by screening and isolation,and optimize its degradation conditions for providing a new way to degrade diuron.【Method】Diuron-degrading strain SL-6 was isolated in the soil of cotton field by enrichment culture,and identified by 16S rDNA and nrdA gene sequence analysis combined with morphological,physiological and biochemical characteristics.HPLC method was used to detect the degradation effect of SL-6 strain on diuron,and the degradation abilities of the strain under different initial concentrations of diuron,inoculation amount,sucrose content,pH and temperature conditions were studied and the degradation conditions were optimized.【Result】Seven strains were isolated from soil of cotton field.Among them,Achromobacter strains SL-6,SL-7 and SL-9 had good degradation effects on diuron and the degradation kinetics conformed to the degradation kinetics equation.Among the three strains,A.xylosoxidans SL-6 had the best degradation effect,with the degradation rate of 94.6%on the 15th day.When the initial concentration of diuron was 200 mg/L,inoculation amount was 15%(φ),carbon source was not added,pH was 8.0 and temperature was 30℃,the degradation rate reached 93.1%after five days.【Conclusion】Strain SL-6 can efficiently degrade diuron,and can be used as a new strain resource.This study provide a basis for further research on microbial degradation of diuron.