Power generation from organic substrate in batch and continuous flow microbial fuel cell operations

Microbial fuel cells (MFCs) are biochemical-catalyzed systems in which electricity is produced by oxidizing biodegradable organic matters in presence of either bacteria or enzyme. This system can serve as a device for generating clean energy and, also wastewater treatment unit. In this paper, production of bioelectricity in MFC in batch and continuous systems were investigated. A dual chambered air–cathode MFC was fabricated for this purpose. Graphite plates were used as electrodes and glucose as a substrate with initial concentration of 30 g l−1 was used. Cubic MFC reactor was fabricated and inoculated with Saccharomyces cerevisiae PTCC 5269 as active biocatalyst. Neutral red with concentration of 200 μmol l−1 was selected as electron shuttle in anaerobic anode chamber. In order to enhance the performance of MFC, potassium permanganate at 400 μmol l−1 concentration as oxidizer was used. The performance of MFC was analyzed by the measurement of polarization curve and cyclic volatmmetric data as well. Closed circuit voltage was obtained using a 1 kΩ resistance. The voltage at steady-state condition was 440 mV and it was stable for the entire operation time. In a continuous system, the effect of hydraulic retention time (HRT) on performance of MFC was examined. The optimum HRT was found to be around 7 h. Maximum produced power and current density at optimum HRT were 1210 mA m−2 and 283 mW m−2, respectively.

► Power generation was investigated in a single MFC at batch and continuous modes. ► Continuous MFCs offer some advantages over batch systems for practical applications. ► Polarity and cyclic voltammetry, were adopted to analyze experimental data. ► OCV was stable for the duration of 72 h of operation time in batch system. ► At optimum HRT (6.7 h), maximum output were 1210 mA m−2 and 283 mW m−2, respectively.