A PAH-degrading strain JI 2 was isolated from oilfield produced water in Mao 8 block of Zhongyuan Oilfield. According to analysis of morphological observation

physiological and biochemical test

16S rRNA gene

house-keeping genes and DNA-DNA hybridization

JI 2 was considered to represent a novel species of the genus Microbacterium. The strain could not only grow in inorganic salt culture medium and utilize naphthalene and pyrene as the sole carbon source

but also degrade mixed naphthalene

phenanthrene

anthracene and pyrene. The four PAHs degradation rates could reach 61.4%

86.6%

69.9% and 18.6%

respectively after 7 d. The viscosity of crude oil treated with JI 2 decreased by 29.3% and degradation rate was 134 mg·d-1. Fourier transform infrared spectra

group composition and GC-MS analysis of the crude oil treated with JI 2 showed that the strain tended to utilize PAHs in aromatic hydrocarbons and resins in crude oil. The relative contents of naphthalene series

phenanthrenseries

thiophene series

fluorene series and chrysene series

C21-triaromatic steroid

pyrene

and benz(a)pyrene decreased after degradation. JI 2 had the capacity to remediate water and soil environment contaminated by PAHs and oil

and provided a feasible way for bioremediation of PAHs and oil pollution.