Isolation of a high molecular weight polycyclic aromatic hydrocarbon-degrading strain and its enhancing the removal of HMW-PAHs from heavily contaminated soil

• An indeno [1,2,3-cd] pyrene (6 rings)-degrading strain, P10, was obtained.
• Strain P10 could also degrade phenanthrene, fluorene and fluoranthene efficiently.
• Strain P10 was re-introduced into contaminated soil.
• Increased removal of HMW-PAHs from contaminated soil was achieved by strain P10.

A high molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs)-degrading strain, designed P10, was isolated from PAHs contaminated soil. Strain P10 was preliminarily identified as Kocuria sp. based on the analysis of 16S rRNA gene sequence. Degradation of individual PAHs was investigated in basal salt medium using PAH as sole carbon and energy source. The results showed that strain P10 could degrade several PAHs including HMW-PAHs, such as fluorene, fluoranthene and indeno[1,2,3-cd]pyrene with degrading percentages of 83.2%, 76.5% and 59.6%, respectively, after incubation for 14 days at 25 °C. Bioremediation experiments of HMW-PAHs heavily contaminated soil were also carried out using strain P10 as inoculum in weathered plots under natural conditions. The results indicated that strain P10 could significantly enhance the removal of HMW-PAHs from the contaminated soil. The removal percentages were increased by about 2-folds for HMW-PAHs in comparison to the non-inoculated one.