Construction of Sugar-based Microbial Fuel Cells by Dissimilatory Metal Reduction Bacteria

Dissimilatory metal reduction bacteria play an important role in the anaerobic environment. Rhodoferax ferrireducens was used to construct a suit of microbial fuel cells with sugars as fuel, and the process and mechanism of electricity generation was studied. Current density was up to 158 mA/m2with the resistance of 510 Ω at the normal temperature. Following 20 days' growth, a large amount of bacteria cells attached to the electrode surface was observed. The planktonic cell protein concentration was 140 mg/L and the attached biomass of electrode surface was 1 180 mg/m2, which indicated quite a few bacteria attached to the electrode. By analyzing the voltage value measured by the data acquisition system, it was proved that microbial electricity generation attributed mainly to the electrochemically and biologically active cells attached to the electrode, while the planktonic cells had no ability to catalyze electricity generation. Furthermore, this kind of microbial fuel cells exhibited a good electrochemical cycle property and proved to be efficient in biomass utilization and energy restoration, as other sugars like fructose, sucrose, even xylose, could be oxidized and finally decomposed, which showed a promising future application in this field.