Isolation and Characterization of a Phenanthrene- Degrading Sphingomonas sp. Strain P2 and Its Ability to Degrade Fluoranthene and Pyrene via Cometabolism

A bacterial strain P2 capable of using phenanthrene as a sole source of carbon and energy was isolated from a lubricant-contaminated soil sample collected from a garage in Prajinburi province, Thailand and identified by 16S rRNA gene sequence analysis to be in the genus of Sphingomonas. The Sphingomonas sp. strain P2 rapidly degraded phenanthrene from 100 mgl to undetectable level by HPLC analysis within 72 h. Besides phenanthrene, this strain was able to degrade a wide variety of polycyclic aromatic hydrocarbons (PAHs) including naphthalene, acenaphthylene, acenaphthene, dibenzofuran, fluorene, and anthracene, meanwhile, it was also capable of co-metabolizing high molecular weight PAHs such as fluoranthene and pyrene in liquid minimum medium supplemented with phenanthrene.