Whole cell electrochemistry of electricity-producing microorganisms evidence an adaptation for optimal exocellular electron transport
| Autor: | Juan M. Feliu, Juan Pablo Busalmen, Abraham Esteve-Nuñez |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
medicine.medical_specialty
Chemistry Otras Ciencias Químicas Microorganism Ciencias Químicas General Chemistry Electrochemistry Electron transport chain Electron Transport Bioelectrochemistry Biochemistry Electrode-reducing bacteria Biophysics medicine Microscopy Electron Scanning Environmental Chemistry Bioenergy Adaptation Whole cell Bacterial outer membrane Geobacter Oxidation-Reduction CIENCIAS NATURALES Y EXACTAS |
| Zdroj: | Environmental sciencetechnology. 42(7) |
| ISSN: | 0013-936X |
| Popis: | The mechanism(s) by which electricity-producing microorganisms interact with an electrode is poorly understood. Outer membrane cytochromes and conductive pili are being considered as possible players, but the available information does not concur to a consensus mechanism yet. In this work we demonstrate that Geobacter sulfurreducens cells are able to change the way in which they exchange electrons with an electrode as a response to changes in the applied electrode potential. After several hours of polarization at 0.1 VAg/AgCl-KCl (saturated), the voltammetric signature of the attached cells showed a single redox pair with a formal redox potential of about -0.08 V as calculated from chronopotentiometric analysis. A similar signal was obtained from cells adapted to 0.4 V. However, new redox couples were detected after conditioning at 0.6 V. A large oxidation process beyond 0.5 V transferring a higher current than that obtained at 0.1 V was found to be associated with two reduction waves at 0.23 and 0.50 V. The apparent equilibrium potential of these new processes was estimated to be at about 0.48 V from programmed current potentiometric results. Importantly, when polarization was lowered again to 0.1 V for 18 additional hours, the signals obtained at 0.6 V were found to greatly diminish in amplitude, whereas those previously found at the lower conditioning potential were recovered. Results clearly show the reversibility of cell adaptation to the electrode potential and point to the polarization potential as a key variable to optimize energy production from an electricity producing population. Fil: Busalmen, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Esteve Núñez, Abraham. Universidad de Alicante; España Fil: Miguel Feliu, Juan. Universidad de Alicante; España |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|