Acetate Degradation of Geobacter anodireducens and Methanosaeta concilii Co-culture with Different Cathode Potentials in Bioelectrochemical System

Abstract

Six bioelectrochemical systems with different applied cathode potentials were designed to examine acetate degradation. All of the systems were cocultured with Geobacter anodireducens and Methanosaeta concilii. Control system was performed similar to bioelectrochemical systems without applied voltage. The experiments were conducted until biogas production ceased. Production of biogas accumulation result showed that -1200 mV had the highest value compared to other treatments but had low acetate removal efficiency which was 83% at the end of experiment. Increased in coulumbic efficiency results that was calculated on daily basis, in line with the increased of current recorded. As an important parameter to assess the amount of electrons available from substrate, coulumbic efficiency could also indicate efficiency of acetate degradation in bioelectrochemical systems. Compared to other bioelectrochemical systems with different applied voltage, performance of -240 mV system was better, considering several dependent parameters measured, including concentration of acetate degradation, biogas accumulation, acetate removal efficiency, current recorded and coulumbic efficiency. This study demonstrated that bioelectrochemical system coupled with carbon dioxide reduction on cathode surface could enhance acetate degradation which may represent an effective strategy to attenuate the impact of shock loads in anaerobic digestion systems.