Degradation of pharmaceuticals, fungicides, and other xenobiotics at micromolar scale with unspecific peroxygenases (UPOs) supported by fungal oxidases: An option in wastewater treatment?

Unspecific peroxygenases (UPOs) from fungi catalyze diverse oxyfunctionalization reactions on a wide range of substrates. Here, we describe a novel approach of their use for the removal recalcitrant substances from waste water. Of 22 environmentally relevant pharmaceuticals, industrial chemicals, and agrochemicals tested, 15 were converted by seven different UPOs when H 2 O 2 was simply added with a pipette or syringe pump. The reaction performance for a selection of substrates could be optimized by two different enzyme-based H 2 O 2 supply systems using glucose oxidase from Aspergillus niger or alcohol oxidase from Pichia pastoris . This increased the conversion rates by a factor of 10 to 50 compared to non-optimized reactions. Finally, a UPO/oxidase system combining two peroxygenases from Agrocybe aegerita and Chaetomium globosum , as well as alcohol oxidase was applied to treat real municipal wastewater containing four widely known pharmaceuticals (diclofenac, ibuprofen, sulfamethoxazole, metoprolol) in micromolar concentration. Complete elimination was achieved in both cases. In future, similar approaches could be used in wastewater treatment as innovative alternatives or supplements to existing methods, provided the enzymes are available in sufficient quantities and at moderate prices. Incidentally, we observed that UPOs can oxidize fungicides of the benzimidazole group, which may explain a possible resistance mechanism of fungi against these widely used pesticides.