Predictability and robustness of anode biofilm to changing potential in microbial electrolysis system

Abstract

Microbial electrolysis systems (MES) facilitate the process of using waste for efficient production of hydrogen thus resulting in lower energy costs compared to conventional hydrogen production. However, the stability and robustness of anode-respiring biofilms often limit long-term MES application. In this study, a 10 L rotating disc bioelectrochemical reactor was used to analyze the anodic biofilm under rapidly changing processing conditions, including changes in anode potential and shear force. A low complexity biofilm formed by Shewanella oneidensis and Geobacter sulfurreducens was studied to determine the boundary conditions for achievable current density and species interaction in large-scale applications. Demonstrating its robustness to the applied changes, the biofilm produced a stable current density of 1.2 A m−2 over 1.5 months. Furthermore, a mathematical model was developed to predict the behavior of the system in terms of current output, which may allow automatic user-defined control of sub-processes in MES reactors in the future.