The influence of the potential on single cell yield coefficients of early stage anode biofilms of Geobacter sulfurreducens
- 1Helmholtz Centre for Environmental Research GmbH - UFZ, Department of Environmental Microbiology, - 04318 Leipzig, Germany (falk.harnisch@ufz.de)
- 22 Helmholtz Centre for Environmental Research GmbH - UFZ, Department Solar Materials, - 04318 Leipzig, Germany
Geobacter sulfurreducens is a gram- rod shaped microorganism and the model system for direct extracellular electron transfer (EET). Although several details of the molecular mechanisms of EET are deciphered [1, 2], there is still a significant lack of knowledge, for instance on kinetics or cell growth. It is the aim of this study to provide information about the influence of the anode potential on yield coefficients on the single cell level, i.e. the moles of substrate consumed or moles of electrons transferred to the anode per cell. This information is highly relevant for physiological as well as technical considerations and for further improvement of bioelectrochemical systems (BES). Therefore, single and double chamber bioelectrochemical reactors were operated in batch mode using either the “standard” graphite rods or a microscopy slide sputter-coated with 10 nm of Cr and 25 nm of AuPd as anode material for allowing analysis of the biofilms with CLSM, as a tool for cell number determination.
We demonstrate that the anode potential and the electrode material has a strong influence on the kinetics of initial growth as well as on the yield coefficients of early stage anode biofilms of Geobacter sulfurreducens, but does not influence other parameters like coulombic efficiency. For instance, in single chamber reactors, the observed lag time, expressed as the time when the biofilm delivered a current density of 1 µA cm-2, was of 1.76±1.02, 6.99±2.26 days and 5.32±1.82 days at -200mV, 0 mV and +200mV (vs. Ag/AgCl sat. KCl) respectively with the sputter-coated glass and of 2.44±0.48 days, 1.38±0.46 days and 1.73±1.45 at -200 mV, 0 mV and +200 mV (vs. Ag/AgCl sat. KCl) respectively using graphite rods.
References
[1] Annu Rev Microbiol. 2012; 66:391-409
[2] Microbial Electrochemical Technology Sustainable Platform for Fuels, Chemicals and Remediation Biomass, Biofuels and Biochemicals 2019, Pages 339-351
How to cite: Scarabotti, F., Korth, B., Rago, L., Bühler, K., and Harnisch, F.: The influence of the potential on single cell yield coefficients of early stage anode biofilms of Geobacter sulfurreducens, biofilms 9 conference, Karlsruhe, Germany, 29 September–1 Oct 2020, biofilms9-143, https://doi.org/10.5194/biofilms9-143, 2020
