Flavin mononucleotide mediated microbial fuel cell in the presence of Shewanella putrefaciens CN32 and iron-bearing mineral

We investigate the workability of electron transfer mediators (ETMs) for the enhanced microbial fuel cell (MFC) operated by Shewanella putrefaciens CN32. In open-circuit, natural ETMs showed 128 ~ 166% of enhancement in the difference of electrical potential compared to that without ETMs (0.41 V), while MFC with synthetic ETMs achieved 200 ~ 250% of enhancement, showing a liner relationship between the electric potentials and ETMs’ redox potentials (R2 = 0.91). Especially, flavin mononucleotide (FMN), the most effective ETM for Shewanella-MFC operation, exhibited the highest potential (0.547 V) and power density (20.28 mW/m2) and generated the maximum current (0.285 mA). The addition of conductive iron-bearing minerals (hematite: 26.27 mW/m2, lepidocrocite: 25.83 mW/m2) enhanced power density of FMN-MFC, while no significant enhancement was observed when soluble iron source (ferric citrate) was added. In addition, MFC containing hematite showed the maximum current (0.37 mA) with 30.8 % of coulombic efficiency.