Enhanced electricity generation of a 1.2-L microbial fuel cell with acclimation of applied voltage

Abstract

The aim of this study was to investigate the effect of acclimation at different applied voltages on the electricity generation and composition of anodic biofilm in microbial fuel cell (MFC). Single-chamber air-cathode 1.2-L MFCs were acclimated by different applied voltages (i.e., 0.5, 1.0, 1.5 and 2.0 V). The maximum power density of 1587 mW/m² and maximum current density of 32.2 ± 0.3 A/m² were obtained in the MFC after the acclimation by 1.0 V, respectively, which were 10.5 and 1610 times that of the unacclimated MFC. The MFC acclimated by 2.0 V could remain in stable operation with an average maximum current density of 7.8 ± 0.1 A/m² and a maximum power density of 1439 ± 30 mW/m² within 40 cycles (∼20 d). The average biomass of the anodic biofilms increased from 3.8 ± 0.9 mg/g before the acclimation to 11.3 ± 1.6 mg/g after the acclimation by 2.0 V. Correspondingly, the anode bacterial viability increased from 0.74 ± 0.02 to 0.91 ± 0.02. The relative abundance of Geoalkalibacter decreased from 18.7 % to 36.1 % before the acclimation to 1.3 %–18.0 % after the acclimation by 2.0 V in the bacterial communities of the anodic biofilms in the MFC. Results from this study should provide an easy way to enhance electrochemically active bacteria acclimation and improve electricity generation in the MFC.