Ligninolytic fungi in bioremediation : screening and evaluation of potential for degradation of PAHs

Abstract

Nowadays Polycyclic Aromatic Hydrocarbons (PAHs) and related pollutants, such as coal tar and creosote, represent a paramount of environmental concern as it has been pointed out by several American and European laws and regulations (i.e. EU Directive 2001/90/CE). Several PAHs have been identified to be hazardous for human health due to carcinogenicity, mutagenicity and teratogenicity. The aim of this research is to determine the efficacy of selected basidiomycetes and ascomycetes in the bioremediation of polycyclic aromatic hydrocarbons (PAHs), with a particular focus onto the possibility to apply white-rot fungi for the bioremediation of creosote in expended wood sleepers. Fungal species which have demonstrated higher resistance to different pollutant concentrations have been further investigated to determine their capability to produce ligninolytic enzymes, such as laccase (E.C. 1.10.3.2), manganese dependent peroxidase (E.C. 1.11.1.13), lignin peroxidase (E.C. 1.11.1.13), as a parameter to evaluate their bioremediation potential. Finally, dual co-culture assays were used to investigate the possibility of enhancing the remediation process effectiveness by means of applying a consortium of microorganism. Composition of coal tar and creosote in railway wood sleepers samples was determined by using analytical methods such as GC-MS, GC-FID, HPLC, UPLC while enzymatic activity was estimated by qualitative enzymatic assay in vitro and UV-visible spectroscopy.