Towards high potential magnetic biocatalysts for on-demand elimination of pharmaceuticals

The present study investigated the applicability of a laccase based bioprocess for the treatment of a mixture containing 13 selected pharmaceuticals. To do so, laccase was immobilized as cross-linked enzyme aggregates (MAC-CLEAs) on amine functionalized magnetic nanoparticles using chitosan/1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDAC) as the cross-linking system. The activity recovery of laccase reached 61.4% under the optimal conditions of MAC-CLEAs formation. The latter exhibited enhanced storage stability over one year at 4 °C and showed better temperature resistance compared to its soluble counterpart. The biocatalysts were properly recycled and the catalytic activity recovery was good even after a hundred and fifty batch reactions. Complete removal of pharmaceuticals like acetaminophen, diclofenac, mefenamic acid, atenolol and epoxy carbamazepine and partial removal of fenofibrate, diazepam, trimethoprim, and ketoprofen by laccase was achieved within 12 h of incubation, whereas efficient removal of indometacin required the presence of mediator.