Isolation of Pendimethalin Degrading Bacteria from Cotton Continuous Cropping Soil and Degradation Characteristics of Strain XSP6

Five strains of pendimethalin-degrading strains were isolated by enrichment culture. To identify the strain, the study used physiology and biochemistry approaches, and analysed the base sequence of the D1/D2 region of 26S rRNA. Also, effects of carbon source concentration, inoculation amount and initial concentration of dimethylpentyl on the degradation of dimethylpentyl by strain XSP6 was determined in this study. It was reported that strain XSP6 had the best degradation performance in 300 mg/L pendimethalin within 5 days, with a degradation rate reached at 50%. Based on the physiological and biochemical analysis of the strain XSP6, combined with the analysis of the base sequence, it was identified as Candida tropicalis. When the inoculation amount was 2.5% and the external carbon source was 2%, the degradation rate of pendimethalin by XSP6 had peaked at 66.2%. This study would provide a theoretical basis for pesticide-contaminated water and soil bioremediation.