A framework for modeling electroactive microbial biofilms performing direct electron transfer.
A modeling platform for microbial electrodes based on electroactive microbial biofilms performing direct electron transfer (DET) is presented. Microbial catabolism and anabolism were coupled with intracellular and extracellular electron transfer, leading to biofilm growth and current generation. The model includes homogeneous electron transfer from cells to a conductive biofilm component, biofilm matrix conduction, and heterogeneous electron transfer to the electrode. Model results for Geobacter based anodes, both at constant electrode potential and in voltammetric (dynamic electrode potential) conditions, were compared to experimental data from different sources. The model can satisfactorily describe microscale (concentration, pH and redox gradients) and macroscale (electric currents, biofilm thickness) properties of Geobacter biofilms. The concentration of electrochemically accessible redox centers, here denominated as cytochromes, involved in the extracellular electron transfer, plays the key role and may differ between constant potential (300 mM) and dynamic potential (3mM) conditions. Model results also indicate that the homogeneous and heterogeneous electron transfer rates have to be within the same order of magnitude (1.2 s(-1)) for reversible extracellular electron transfer.
UFZ - Helmholtz-Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, 04318 Leipzig, Germany.
Benjamin
B
Korth
UFZ - Helmholtz-Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, 04318 Leipzig, Germany.
Luis F M
LF
Rosa
UFZ - Helmholtz-Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, 04318 Leipzig, Germany. Electronic address: falk.harnisch@ufz.de.
Falk
F
Harnisch
Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
Cristian
C
Picioreanu
D001674:Bioelectric Energy Sources; D018441:Biofilms / Q000254:growth & development*; D004553:Electric Conductivity; D004579:Electron Transport; D045302:Geobacter / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D042541:Intracellular Space / Q000378:metabolism; D008954:Models, Biological
Bioelectrochemical systems; Electrochemically active microbial biofilms; Extracellular electron transfer; Microbial electrochemical technologies; Model