Isolation and Identification of a Di-(2-Ethylhexyl)Phthalate-Degrading Bacterium and Its Role in the Bioremediation of a Contaminated Soil

Abstract Di-(2-ethylhexyl) phthalate (DEHP) is a high-molecular-weight phthalate ester (PAE) that has been widely used in the manufacture of polyvinylchloride and contributes to environmental pollution. The objectives of the present study were to isolate a DEHP degrader that can utilize DEHP as a carbon source and to investigate its capacity to biodegrade DEHP in both liquid culture and soil. A bacterial strain WJ4 was isolated from an intensively managed vegetable soil, which was contaminated with PAEs. The strain WJ4 was affiliated to the genus Rhodococcus and was able to remove DEHP from soil effectively. A period of only 7 d was required to degrade about 96.4% of DEHP (200 mg L −1 ) in the liquid culture, and more than 55% of DEHP (1.0 g kg −1 ) in the artificially contaminated soil was removed within 21 d. Furthermore, Rhodococcus sp. strain WJ4 had a strong ability to degrade DEHP without additional nutrients in liquid minimal medium culture and DEHP-contaminated soil and to degrade the homologue of DEHP in both liquid culture and soil. Strain WJ4 represents a novel tool for removing PAEs from contaminated soils and it may have great potential for application in the remediation of environmental pollution by PAEs.