Application of spent mushroom (Lentinula edodes) substrate and acclimated sewage sludge on the bioremediation of polycyclic aromatic hydrocarbon polluted soil

Abstract

Two widespread agro-industrial wastes, spent mushroom substrate of Lentinus edodes (SMS) and acclimated sewage sludge (ASS), were investigated for the remediation of multi-polycyclic aromatic hydrocarbon (multi-PAH) polluted soil. Results clearly showed that multi-PAH contaminated soil was not amendable to natural attenuation. In contrast, application of sterilized ASS and SMS significantly stimulated resident microbes in the soil and consequently enhanced the removal efficiency of PAHs. Active ASS and SMS exerted a better effect than sterilized ones. ASS improved total bacterial abundance better, and it had a better degradation effect on low molecular weight PAHs than SMS, while SMS improved the fungal population better and had a better effect on the degradation of heavy molecular weight PAHs by its ligninolytic enzymes. The combination of ASS–SMS exerts the best PAH removal and soil improvement effect with degradation rates beyond 94% in all PAHs. The present study strongly supports SAS and SMS as amendments for the remediation or the improvement of environmental soil which could also open a new approach for recycling agro-industry waste.