Bioremediation of soils contaminated with petroleum solid wastes and drill cuttings by Pleurotus sp. under different treatment scales

Wastes from the oil industry represent one source of soil pollution with a great environmental impact. Both drill cuttings and crude residues are delivered to the soil and produce toxic effects, mainly due to the polycyclic aromatic hydrocarbons. Various bioremediation technologies have been implemented to restore the soil quality and the natural auto depuration capabilities, amongst them: composting, bioaugmentation and biostimulation. These bioremediation techniques promise to be eco-friendlier and cheaper alternatives than other approaches. In this work we have evaluated several strains of Pleurotus sp. for their effect on the bioremediation of oil-contaminated wastes and drill cuttings disposed in storage tanks or in open-air soil lots for many years. Our results support that combined natural attenuation mechanisms and directed fungal biodegradation activities, could be promising strategies to remediate heavily petroleum polluted soils and drilling wastes both at the laboratory and in field conditions. Furthermore, we present data that supports the Pleurotus genus as able to degrade asphaltenes, the most recalcitrant fraction of petroleum. In addition, the annotation of the genome representative of Pleurotus ostreatus revealed clues about the possible enzymatic factors related to the mobilization of carbon from both aromatics and aliphatic derivatives from petroleum hydrocarbons in the genus. This study proposes an approach that at the same time can treat soils contaminated with waste from drill cuttings and bottoms of crude storage tanks.