Characterization of pyrene degradation by Pseudomonas sp. strain Jpyr-1 isolated from active sewage sludge

•Pseudomonas sp. Jpyr-1 could use pyrene as the sole carbon source.•Strain Jpyr-1 showed a very high degradation rate of pyrene.•Existence of the second PAH influenced pyrene degradation at different levels.•Metabolic route of Jpyr-1 to degrade pyrene was through the o-phthalate pathway. Using pyrene as a sole carbon, a new polycyclic aromatic hydrocarbons (PAHs)-degrading bacterial strain was isolated from the active sewage sludge. This strain was identified as Pseudomonas sp. Jpyr-1 by 16S rRNA gene sequence analysis. The maximum degradation rate of pyrene was 3.07mgL−1h−1 in 48h incubation with initial pyrene concentration of 200mgL−1. Moreover, in binary system consisting of pyrene and another PAH, the enzyme system of Jpyr-1 showed a preference toward pyrene. Furthermore, competitive inhibition of pyrene degradation by other PAH compounds occurred in the binary system. Jpyr-1 could also rapidly degrade other PAHs, such as benzanthracene, chrysene and benzo[a]pyrene. Moreover, several metabolites were detected during pyrene degradation which indicated that Jpyr-1 degraded pyrene through the o-phthalate pathway. Taken together, these results indicated that Pseudomonas sp. Jpyr-1 was a new PAHs-degrading strain that might be useful in the bioremediation of sites contaminated with PAHs.