Performance of Hybrid Process Constructed Wetland-Microbial Fuel Cell for Melanoidin Degradation and Simultaneous Electricity Generation

Abstract

Melanoidin is the main cause of the dark brown color of the palm oil mill effluent (POME) that form under the Maillard reaction. In this study, the constructed wetland integrated with microbial fuel cell (CW-MFC) has been developed for melanoidin removal from the POME and simultaneously electricity generation as a by-product. The macrophyte Dieffenbachia sp. has been used as a biocatalyst on the cathode electrode and the oxidoreductase-producing bacterium Bacillus lichenformis with laccase and manganese peroxidase activity has been used as an anodic biocatalyst. The maximal melanoidin removal, chemical oxygen demand (COD) removal, enzyme activity, and power output were monitored. The maximal laccase and manganese peroxidase activities of 1.60 ± 0.10 U/mL and 1.45 ± 0.05 U/mL were found during melanoidin degradation. In addition, the maximal melanoidin removal of 93.59 ± 0.10% and 95.12 ± 0.15% were achieved respectively. When the maximal power density of 0.18 ± 0.01 mW/m3 was generated. This study gained new knowledge about using the CW-MFC system as a biological treatment process of the melanoidin content in the POME and simultaneously generated electrical energy as a by-product. HIGHLIGHTS The coupling process of constructed wetland and the microbial fuel cell is promising for the melanoidin removal of the POME The maximal melanoidin removal of 93.59 % was gained The maximal power output of 0.18 mW/m3 was generated from this system GRAPHICAL ABSTRACT