Isolation and identification of a chlorimuron-ethyl-degrading bacterium and optimization of its degradation conditions

Abstract:

In order to solve the problem of soil, water pollution and sensitive crop drug damage caused by chlorosulfuron residue, and to provide degradation strain resources for microbial remediation of contaminated soil, a chlorimuron-ethyl-degrading strain T9DB-01 was isolated from chlorosulfuron contaminated soil by the method of enrichment culture and step by step domestication. Strain T9DB-01 was identified as Pseudomonas sp. by morphological characteristics, physiological and biochemical analysis and 16S rDNA gene sequence analysis. The effects of temperature, pH value, substrate concentration, medium volume, and inoculation volume on the degradation of chlorsulfuron-methyl by strain T9DB-01 were investigated by single factor experiment. The degradation conditions of chlorosulfuron by strain T9DB-01 were optimized by orthogonal test and verification. Results show that 30 °C, pH 8.0, inoculum 4%, liquid volume 100 mL/250 mL, substrate concentration of 200 mg/L, cultured for 5 d, the strain degraded 93.7% chlorsulfuron-methyl. The degrading strain has certain application potential for bioremediation of chlorsulfuron-contaminated soil.

Key words:chlorimuron-ethyl, degradation bacterium, Pseudomonas sp., optimization of degradation conditions