Isolation and Characterization of the Phenol Degradation Bacterium Diaphorobacter P2 Strain from Coking Wastewater

A aerobic bacterium strain P2 isolated from coking wastewater, was able to utilize phenol, o-cresol and pyridine as its sole carbon and energy source. The morphological properties and the phylogenetic analysis based on 16S rDNA sequences showed strain P2 belonged to the genus Diaphorobacter sp.. The optimum biodegradation of phenol was 37°C, pH 7.0-9.0 and 0.25% NaCl , respectively. The growth arrearage period was prolonged with the phenol concentration. The growth of Diaphorobacter P2 and phenol-degradation were inhibited completely by 50 μmol/L metal ions, such as Cu2 +, Ni2+, Cd2+ or Cr6+. Orthogonal experiment indicated the order of metal toxicity to biodegradation of P2 was Zn2+>Mn2+>Pb2+ under various heavy-metal compounds. The phenol biodegradation in coking wastewater supplemented with 2/3 beef extract peptone medium was degraded fully in 3 days, indicating that nutrient solution was beneficial for P2 growth and phenol degradation in wastewater. Those results suggest that the Diaphorobacter P2 has potential for treatment of coking wastewater.