The Degradation of Pharmaceutical Pollutants in Wastewater Catalyzed by Chloroperoxidase and the Construction of Chloroperoxidase H105R Mutant

Abstract

Non-steroidal anti-inflammatory drugs (NSAIDs), such as diclofenac and naproxen, are widely used for the treatment of arthritis, ankylosing spondylitis, and acute muscle pain. However, most NSAIDs are usually not metabolized and simply pass through human body. These drugs are difficult to be decomposed by general waste treatment strategies and have caused serious environmental concerns. Here we report a rapid and efficient enzymatic degradation of diclofenac and naproxen by chloroperoxidase (CPO), a heme protein isolated from Caldarimyces fumago (C. fumago). Complete dagradation of diclofenac and naproxen was achieved in only 9 and 7 min for diclofenac and naproxen, respectively, under mild conditions with nanomolar enzyme concentration. The degraded products were identified by both HPLC-MS and NMR, suggesting the involvement of multiple steps in CPO catalyzed degradation of the two drug molecules. Moreover, our work demonstrated that CPO treatment followed by existing bioremediation technologies (activated sludge) greatly improved the efficiency and completeness of decontaminating these two drugs from waste water. Most significantly, our eco-toxicity test using green algae, Chlorella Pyrenoidos, showed that the products had noticeably lower toxicity than the parent drugs, demonstrating the potential of CPO in large-scale treatment of sewage contaminated with diclofenac and naproxen.