Effects of bio- and abio-factors on electricity production in a mediatorless microbial fuel cell

Microbial fuel cell (MFC) attracts growing efforts as a kind of environmentally friendly biotechnology. This study examined effects of the bio-factors (anode inoculums species, inoculums concentration), as well as abio-factors (cathode electron acceptor and proton exchange material) on electricity production of a dual-chamber mediatorless MFC in fed-batch mode. MFCs inoculated with pure culture (Rhodoferax ferrireducens) and mixed culture (activated sludge) obtained the close peak voltages of around 0.18 V and had the similar coulombic yields of about 75 C using monosodium glutamate wastewater (MGW) as substrate. MFCs with different concentrations of inoculums (5%, 10% and 15%) also achieved the similar peak values of around 0.2 V after 30 days’ growth although they were different at the early stage. By replacing cathode oxygen-saturated solution with 10 mmol/L Fe(III)NTA or 10 mmol/L K3Fe(CN)6 solutions, voltage output nearly doubled (0.35 V). However the replacing of proton exchange membrane with salt bridge leaded to a marked decrease of voltage output. These results suggest that electricity production was more significantly influenced by cathode electron acceptor and proton exchange material, less affected by the inoculums species and inoculums concentration.