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

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.