Bioremediation of polycyclic aromatic hydrocarbons contaminated soil with Monilinia sp.: degradation and microbial...

Microcosms were set up with a PAHs-contaminated soil using biostimulation (addition of ground corn cob) and bioaugmentation (inoculated with Monilinia sp. W5-2). Degradation of polycyclic aromatic hydrocarbons and microbial community were examined at the end of incubation period. After 30 days, bioaugmented microcosms showed a 35+/-0% decrease in total PAHs, while biostimulated and control microcosms showed 16+/-9% and 3+/-0% decrease in total PAHs, respectively. Bioaugmented microcosms also revealed 70+/-8% and 72+/-2% decreases in benzo[a]pyrene and anthracene, respectively, while the values for biostimulated and control microcosms were much lower. Detoxification of soils in bioaugmented microcosms was confirmed by genetic toxicity assay, suggesting important role of fungal remediation. Molecular fingerprint profiles and selective enumeration showed biostimulation with ground corn cob increased both number and abundance of indigenous aromatic hydrocarbons degraders and changed microbial community composition in soil, which is beneficial to natural attenuation of PAHs. At the same time, bioaugmentation with Monilinia strain W5-2 imposed negligible effect on indigenous microbial community. This study suggests that fungal remediation is promising in eliminating PAHs, especially the part of recalcitrant and highly toxic benzo[a]pyrene, in contaminated soil. It is also the first description of soil bioremediation with Monilinia sp.