Isolation, identification, and acetochlor-degrading potential of a novel Rhodococcus sp. MZ-3

A new species of Rhodococcus, designated strain MZ-3, which could degrade acetochlor efficiently were isolated and identified. The isolate could degrade and utilize acetochlor as the sole source of carbon, nitrogen, and energy for growth. The optimal conditions for the degradation and growth of MZ-3 were pH 7.0 and 30°C. Under these conditions, this strain could completely degrade 200 mg/L of acetochlor within 12 h of incubation. During the biodegradation process, the enantioselectivity of the strain was investigated using a chiral high-performance liquid chromatography (HPLC) system. However, no obvious enantioselectivities were found. 2-chloro-N-(2-methyl-6-ethylphenyl) acetamide (CMEPA) was detected as the intermediate using liquid chromatography-mass spectrometry (LC-MS) analyses. Our results suggest that strain MZ-3 might be a promising microorganism for the bioremediation of acetochlor-contaminated environments because of its acetochlor-degrading performance.