Isolation and Characterization of a Novel Polycyclic Aromatic Hydrocarbon-Degrading Bacterium, Sphingopyxis sp strain M2R2, Capable of Passive Spreading Motility Through Soil

A novel bacterium within the genus Sphingopyxis is described and its suitability as a bioremediation inoculum is evaluated. Sphingopyxis sp. strain M2R2 was isolated from a polycyclic aromatic hydrocarbon-polluted site and can use both phenanthrene and naphthalene as a sole carbon source in liquid and solid media. It can also co-metabolize fluorene in the presence of phenanthrene. Strain M2R2 can mineralize phenanthrene to CO2 and can utilize the substrate in the presence of glucose. Strain M2R2 is capable of nonchemotactic, passive spreading motility on and through agar media, which is induced by the presence of phenanthrene. It is also capable of motility through phenanthrene-spiked packed sand. The range of materials through which this bacterium can travel along with its high spreading velocity make Sphingopyxis sp. strain M2R2 a good candidate for further field study and inclusion in bioremediation strategies of polycyclic aromatic hydrocarbon polluted soils.