Isolation of Phenanthrene-degrading Microorganisms and Analysis of Metabolites of Phenanthrene

Microbial degradation has been suggested as the best way to remove polycyclic aromatic hydrocarbons (PAHs) from contaminated environment. Therefore, this study aims to evaluate the potential of phenanthrene-degrading microorganisms, isolated from the PAHs contaminated soil of arable land, oil gas plant, and wood preservation plant. The results of such an evaluation allowed the selection of those microorganisms with ability to degrade phenanthrene, added as the only carbon and energy source to a medium. Degrading phenanthrene microorganisms in 3 mixed cultures (GY2 represented culture of microorganism from the oil gas plant soil, GS3 represented that from the arable land and GM2 represented that from the word preservation plant) were enriched by the water-silicon oil biphasic system. In the mineral salts medium under initial phenanthrene concentration of 100 mg·L-1 the removal rates of phenanthrene were 99.9%, 99.9% and 91.9%, respectively after 72 hours. One preponderant bacterial strain, isolated from mixed GY2 culture and obtained from pure GY2B culture, can degrade 99.1% of the phenanthrene in the same condition after 48 hours. 1-hydroxy-2-naphthoic acid and 1-naphthol were identified as the major metabolites in the mixed GY2 culture and pure GY2B culture. Additional, salicylic acid was detected as a metabolite in pure GY2B culture.