Real-time measurements of the redox states of c-type cytochromes in electroactive biofilms: a confocal resonance Raman microscopy study
| Autor: | Damien J. Batstone, Bogdan C. Donose, Diego Millo, Bernardino Virdis |
|---|---|
| Přispěvatelé: | Biophysics Photosynthesis/Energy |
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Time Factors
Anatomy and Physiology lcsh:Medicine 02 engineering and technology Acetates Spectrum Analysis Raman Photochemistry Biochemistry 01 natural sciences Energy-Producing Processes Microbial Physiology Electrochemistry lcsh:Science Geobacter sulfurreducens Microscopy Confocal Multidisciplinary biology Chemistry 021001 nanoscience & nanotechnology Standard electrode potential Electrode symbols Cyclic voltammetry 0210 nano-technology SDG 6 - Clean Water and Sanitation Electromagnetic Phenomena Oxidation-Reduction Research Article Biotechnology Cytochrome c Group Electrons Bioenergetics 010402 general chemistry Microbiology Redox symbols.namesake Biology Electrodes Microbial Metabolism Electrode Potentials lcsh:R Substrate (chemistry) Bacteriology biology.organism_classification 0104 chemical sciences Kinetics Redox gradient Electrochemical Cells 13. Climate action Biofilms Biocatalysis lcsh:Q Physiological Processes Energy Metabolism Bacterial Biofilms Raman spectroscopy |
| Zdroj: | PLoS ONE, 2014(9). Public Library of Science PLoS ONE, Vol 9, Iss 2, p e89918 (2014) Virdis, B, Millo, D, Donose, B C & Batstone, D J 2014, ' Real-time measurements of the redox states of c-type cytochromes in electroactive biofilms: a confocal resonance Raman microscopy study ', PLoS ONE, vol. 2014, no. 9, pp. e89918 . https://doi.org/10.1371/journal.pone.0089918 PLoS ONE |
| ISSN: | 1932-6203 |
| DOI: | 10.1371/journal.pone.0089918 |
| Popis: | Confocal Resonance Raman Microscopy (CRRM) was used to probe variations of redox state of c-type cytochromes embedded in living mixed-culture electroactive biofilms exposed to different electrode polarizations, under potentiostatic and potentiodynamic conditions. In the absence of the metabolic substrate acetate, the redox state of cytochromes followed the application of reducing and oxidizing electrode potentials. Real-time monitoring of the redox state of cytochromes during cyclic voltammetry (CV) in a potential window where cytochromes reduction occurs, evidenced a measurable time delay between the oxidation of redox cofactors probed by CV at the electrode interface, and oxidation of distal cytochromes probed by CRRM. This delay was used to tentatively estimate the diffusivity of electrons through the biofilm. In the presence of acetate, the resonance Raman spectra of young (10 days, j = 208 ± 49 µA cm(-2)) and mature (57 days, j = 267 ± 73 µA cm(-2)) biofilms show that cytochromes remained oxidized homogeneously even at layers as far as 70 µm from the electrode, implying the existence of slow metabolic kinetics that do not result in the formation of a redox gradient inside the biofilm during anode respiration. However, old biofilms (80 days, j = 190 ± 37 µA cm(-2)) with thickness above 100 µm were characterized by reduced catalytic activity compared to the previous developing stages. The cytochromes in these biofilm were mainly in the reduced redox state, showing that only aged mixed-culture biofilms accumulate electrons during anode respiration. These results differ substantially from recent observations in pure Geobacter sulfurreducens electroactive biofilms, in which accumulation of reduced cytochromes is already observed in thinner biofilms, thus suggesting different bottlenecks in current production for mixed-culture and G. sulfurreducens biofilms. |
| Databáze: | OpenAIRE |
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