A novel laccase-catalyzed cathode for microbial fuel cells

A microbial fuel cell (MFC) cathode was developed by immobilizing the enzyme, laccase, in polymer matrix (Nafion) on carbon paper together with carbon nanoparticles and a redox mediator (2,2′-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt). The results from characterization of the immobilized laccase on the electrode indicate that the immobilization preserved laccase activity. Electrochemical measurements demonstrate that the Nafion film can facilitate electron exchange between the electroactive domain of laccase and the electrode. The electrocatalysis capabilities of the laccase-coated electrode were characterized by cyclic voltammogram (CV), which showed the electrode facilitated direct and surface-controlled redox reactions in a 0.1 M citrate buffer solution (pH 5.0). Additionally, when installed in a two-chamber MFC, the laccase-coated cathode demonstrates a strong catalytic potential that is comparable to a Pt-catalyzed cathode.