Integrating engineering design improvements with exoelectrogen enrichment process to increase power output from microbial fuel cells

摘要

Microbial fuel cells (MFC) hold promise as a green technology for bioenergy production. The challenge is to improve the engineering design while exploiting the ability of microbes to generate and transfer electrons directly to electrodes. A strategy using a combination of improved anode design and an enrichment process was formulated to improve power densities. The design was based on a flow-through anode with minimal dead volume and a high electrode surface area per unit volume. The strategy focused on promoting biofilm formation via a combination of forced flow through the anode, carbon limitation, and step-wise reduction of external resistance. The enrichment process resulted in development of exoelec-trogenic biofilm communities dominated by Anaeromusa spp. This is the first report identifying organisms from the Veillonellaceae family in MFCs. The power density of the resulting MFC using a ferricyanide cathode reached 300 Wm~(-3) net anode volume (3220 mWm~(-2)), which is about a third of what is estimated to be necessary for commercial consideration. The operational stability of the MFC using high specific surface area electrodes was demonstrated by operating the MFC for a period of over four months.