Ability of white-rot fungi to remove selected pharmaceuticals and identification of degradation products of ibuprofen by Trametes versicolor

Abstract

A screening using four white-rot fungi ( Trametes versicolor, Irpex lacteus, Ganoderma lucidum and Phanerochaete chrysosporium) was performed on the degradation of 10 mg L −1 of ibuprofen (IBU, anti-inflammatory), clofibric acid (CLOFI, lipid regulator) and carbamazepine (CARBA, antiepileptic/analgetic) after 7 d of incubation. Whereas IBU was extensively degraded by all the fungi tested, T. versicolor was the only strain able to degrade either CLOFI (∼91%) and CARBA (∼58%), although the latter was also degraded by G. lucidum (∼47%). In vitro experiments using manganese peroxidase and laccase-mediator system showed that extracellular fungal enzyme systems did not appear to play a role in the first step of degradation. However, our in vivo studies using the cytochrome P450 inhibitors 1-aminobenzotriazole and piperonyl butoxide suggested that the cytochrome P450 system may be involved in the first step of CLOFI and CARBA oxidation by T. versicolor. During the very early stages of IBU degradation by T. versicolor, two hydroxylated metabolites were detected: 1-hydroxy ibuprofen and 2-hydroxy ibuprofen. These byproducts were subsequently degraded by the fungus to 1,2-dihydroxy ibuprofen, that was not reported in biological systems to date. Furthermore, these results are of particular interest because CLOFI and CARBA are highly persistent in the aquatic environment and they pass unchanged or poorly transformed in wastewater treatment plants.