Enhancing bioelectricity generation and removal of copper in microbial fuel cells with a laccase-catalyzed biocathode

Abstract White rot fungi (WRF) are planted on the cathode of a ceramic microbial fuel cell (C-MFC) to enhance its removal of copper from wastewater. When P. eryngii was planted in the air cathode of a fungal electrode assembly MFC (FEA-MFC), the observed maximum power density was of 41.3 mW/m2, which was 3.52 times that without planted WRF. WRF used the obtained Cu2+ to increase laccase activity by 1.68-fold to 462 U/L. FEA-MFC removed more than 99% of Cu2+ (50–200 mg/L), showing that it can feasibly remove a high concentration of Cu2+. Planting WRF increased the peak current of the C-MFC by 1.65 times, as determined by cyclic voltammetry. The C-MFC that contained WRF reduced the internal resistance of the MFC by 27.2%, indicating that the laccase that was released by WRF was effectively delivered to the cathode of the MFC and improved the power output by approximately 2.53-fold. Cu2+ in the wastewater was effectively removed and formed a deposit on the cathode, which was identified as Cu(OH)2.