The ability of the white rot fungus Pleurotus ostreatus to biodegrade 2-naphthalenesulfonic acid polymers (2-NSAP) contained in a petrochemical wastewater was evaluated. The characterization of the wastewater and a LC-MS identification of polymers were performed. Biodegradation experiment was conducted in batches with and without the addition of a carbon source (glucose, corn starch, cellulose and lignin). It has been demonstrated that, in presence of a suitable carbon source, P. ostreatus is able to remove NSAP ranging from trimers to decamers. Interestingly, all the carbon sources utilized, despite the different velocities, allowed to degrade about 60-70% of the oligomers. Furthermore, respirometric tests showed that the fungal treatment was also able to significantly increase the bCOD/COD ratio, going from 9% (raw wastewater) up to 57%. This is clearly correlated with the enhancement in oligomers depolymerization confirming that the fungal action is not a mineralization of NSAP, but an increase of their biodegradability. (C) 2014 Elsevier Ltd. All rights reserved.