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Highly efficient bio-catalytic oxygen reduction coupled to long-range electron transport in cable bacteria
Dmitrii Pankratov1, Anwar Hiralal2, Silvia Hidalgo Martinez1
1Geobiology, Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium.
Bioelectrochemistry (Amsterdam, Netherlands)
|February 22, 2026
Summary
Cable bacteria transfer electrons over long distances using conductive fibers. Oxygen reduction occurs via periplasmic enzymes, not the fibers themselves, involving cytochromes.
Area of Science:
- Microbiology
- Electrochemistry
- Biogeochemistry
Background:
- Multicellular cable bacteria form living electrochemical cells.
- They transfer electrons over centimeter distances via conductive fibers.
- Sulfide oxidation and oxygen reduction occur at opposite ends.
Purpose of the Study:
- Investigate the mechanism of oxygen reduction linked to long-distance electron transport.
- Determine the role of conductive fibers in oxygen reduction.
- Clarify the electron transfer pathway in cable bacteria.
Main Methods:
- Electrochemical characterization of native filaments and extracted fiber skeletons.
- Chemical inhibition assays on native filaments.
- Analysis of electron transport and oxygen reduction rates.
Main Results:
- Fiber skeletons facilitate longitudinal electron transport but are not electrochemically active towards oxygen.
- Native filaments exhibit high oxygen reduction rates.
- Cytochromes are involved in electron transfer from fibers to oxygen.
Conclusions:
- Oxygen reduction is mediated by periplasmic or inner membrane enzyme systems, not the conductive fibers.
- Diffusible c-type cytochromes shuttle electrons between respiratory complexes and the fiber network.
- This resolves a key aspect of cable bacteria's electrogenic metabolism and potential in Bio-electrochemical Systems.
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