[Characterization of phenol-degrading Rhodococcus sp. strain P1 from coking wastewater].

OBJECTIVE: The removal of phenolic compounds was a key problem for coking wastewater treatment. This study focused on the isolation and characterization of anefficient phenol-degrading bacterial strain from coking wastewater. METHODS: Phenol-degrading bacterium was screened by using phenol as the sole carbon source, strain was identified according to the morphological properties and 16S rRNA sequence analysis, the phenol-degrading characteristics and the potential for removal of phenol in the coking wastewater were evaluated. RESULTS: Strain P1 was identified as the genus Rhodococcus sp. with morphological properties and 16S rRNA gene sequence. This strain could survive at the presence of phenol with concentration up to 1400 mg/L. The optimal conditions for biodegradation of 600 mg/L phenol in mineral medium were at 32 - 42 degrees C, pH 7.0 and 0 - 4% NaCl. The phenol-degrading efficiency by P1 strain was different in response to various heavy metal ions, Ni2+, Mn2+ and low concentration of Pb2+ had no effect on the phenol degradation. However, Cu2+, Ni2+ and Cd2+ seriously inhibited phenol degradation by strain P1. The 279.9 mg/L phenols from 1/3 coking wastewater were completely degraded after incubation for 2 days. CONCLUSION: Strain P1 is an efficient phenol-degrading bacterium and has of the potential for removing phenolic compounds in coking wastewater.