Operation of stirred tank reactors (STRs) and fixed-bed reactors (FBRs) with free and immobilized Phanerochaete chrysosporium for the continuous removal of pharmaceutical compounds

Abstract

Stirred tank reactors (STRs) and fixed-bed reactors (FBRs) were applied for the removal of diclofenac, ibuprofen, naproxen, carbamazepine and diazepam by Phanerochaete chrysosporium. The operation of STRs with free pellets and immobilized fungus attained stable operation for 50 days. Both bioreactors achieved high removal efficiencies for diclofenac, ibuprofen and naproxen while partial removal of carbamazepine and diazepam. The configuration of the FBR maintained a steady and feasible operation for 100 days with complete removal of diclofenac, ibuprofen and naproxen regardless of the aeration system (air or oxygen) and remarkably high removal percentages of carbamazepine and diazepam: 60–90%. The extraction of the target compounds from the biomass and the support showed low residual concentrations of all the compounds both on fungal pellets and on the support of the FBR. Only significant values were detected in the STR with immobilized mycelium, demonstrating partial adsorption. A tentative identification of the degradation products of the three anti-inflammatories was performed, indicating the presence of 4-hydroxy-diclofenac, 1-hydroxy-ibuprofen-, 6-O-desmethyl-naproxen, as the major degradation products of the three parent compounds.