Isolation of chloracetanilide herbicides-degrading bacterium Y3B-1 and its degradability to chloracetanilide herbicides

Abstract

A chloracetanilide herbicides-degrading bacterium strain, Y3B-1, was isolated from activated sludge of a wastewater treatment facility. According to the physiological and biochemical characteristics and the homology analysis of 16S rDNA sequence, strain Y3B-1 was identified preliminarily as Paracoccus sp. The degradation characteristics of strain Y3B-1 to various chloracetanilide herbicides under various conditions. The results indicated that strain Y3B-1 was able to used acetochlor as sole carbon source, and it also degraded acetochlor, butachlor and pretilachlor, but not metolachlor. The degradation rate of acetochlor, butachlor and pretilachlor by strain Y3B-1 for 3 d were 86.7%, 65.5% and 69.1%, respectively. The optimum pH and temperature for acetochlor degradation by strain Y3B-1 were 7.0 and 30 °C, respectively. Increasing initial inoculum size and additional nutrients significantly promoted the degradation efficiencies of acetochlor by strain Y3B-1.