Modeling the impact of interspecies competition on performance of a microbial fuel cell.

Previous models of biofilms growing in a microbial fuel cell (MFC) have primarily focused on modeling a single growth mechanism: growth via a conductive biofilm matrix, or growth utilizing diffusible electron shuttles or mediators. In this work, we implement both flavors of models in order to explore the competition for space and nutrients in a MFC biofilm populated by both species types. We find that the optimal growth conditions are for bacteria that utilize conductive EPS provided a minimal energy used to create the EPS matrix. Mediator-utilizing bacteria do have favorable niche regions, most notably close to the anode and where exposed to the bulk inflow, where oxidized mediator is readily available.