Enzymatic and microbial transformation assays for the evaluation of the environmental fate of diclofenac and its metabolites

► Deconjugation of phase II metabolites may explain the observed low removal of diclofenac. ► Enzymatic transformation of diclofenac was studied using rat S9. ► Microbial transformation of diclofenac and its metabolites was studied. ► Laboratory two-step enzymatic and biodegradability assay was useful for evaluating transformation of diclofenac.