High current production of Shewanella oneidensis with electrospun carbon nanofiber anodes is directly linked to biofilm formation
1We study the current production of Shewanella oneidensis MR-1 with electro-spun carbon fiber anode materials and analyze the effect of the anode morphology on the micro-, meso-and macroscale. The materials feature fiber diameters in the range between 108 nm and 623 nm, resulting in distinct macropore sizes and surface roughness factors. A maximum current density of (255{+/-} 71) {micro}A cm-2 was obtained with 286 nm fiber diameter material. Additionally, micro-and mesoporosity were introduced by CO2 and steam activation which did not improve the current production significantly. The current production is directly linked to the biofilm dry mass under anaerobic and micro-aerobic conditions. Our findings suggest that either the surface area or the pore size related to the fiber diameter determines the attractiveness of the anodes as habitat and there-fore biofilm formation and current production. Reanalysis of previous works supports these findings.