Development of immobilised cell based electrode for usage in microbial fuel cell

Abstract

Microbial fuel cell (MFC) is a kind of biological fuel cells that produce electricity through utilization of microorganisms. The efficiency of MFC performance is based on how well the electron is transferred and finally flows through an external circuit to complete electrical circuit. However, the power density produced by MFC generally is still very low and one of the major reasons is due to high internal resistance imposed by macro environment of an MFC. In the present research, the objective was to develop bio-based anode or bioanode and its usage in the MFC for power production. The bioanode was developed by mixing cells solution and activated carbon overnight before adding alginate and subjected to homogenisation. The mixture was then immobilised using entrapment method to obtained uniform beads. Initial study was conducted using glucose as fuel and both open circuit voltage (OCV) and closed circuit voltage (CCV) production were evaluated using a single chambered MFC. Results show that OCV increased gradually and still increased after 6 h of operation compared to free cells. The highest OCV was achieved after 9 h of operation (0.3 V) compared to free cells based MFC (0.2 V) and maintained for 15 h of operation. In CCV profile for free cells show a decrease in voltage generated but then rapidly increased which indicates a ‘power-overshoot’ phenomenon which was not observe in immobilised based bioanode MFC. The maximum OCV was 2-fold higher for immobilised based bioanode compared to free cells. In addition, the sustainability and reproducibility of power production was achieved by operating MFC in Fed-batch mode and results show that the system was stable and able to achieve in average 3.0 x 10-3 % of Coulombic Efficiency (CE).