---
title: "Extracellular electron transfer"
type: "entity"
entity_kind: "concept"
status: "hub"
canonical_name: "extracellular electron transfer"
aliases: ["EET"]
first_seen: "2026-07-11T00:00:00.000Z"
writer_model: "claude-opus-4-8"
connects_to: ["Geobacter sulfurreducens","cable bacteria","microbial nanowires","cytochrome","bioelectronics"]
seek_code_commit: "649b1a4"
---


The physiological and biogeochemical phenomenon by which microbes move
electrons across their outer membrane to acceptors outside the cell — enabling
mineral (metal-oxide) reduction, current generation in microbial fuel cells,
and sediment-scale redox coupling. It is the umbrella under which several
distinct conduction mechanisms sit, and matters to this vault as the concept
that bridges its otherwise-separate electromicrobiology notes: the contested
*Geobacter* nanowire (heme-based cytochrome polymers vs. conductive pili) and
the cable-bacteria wire (a non-redox, metal-like sulfur-ligated nickel
cofactor). Different organisms, different physics, same problem — getting an
electron out of a cell and somewhere useful.

## References
- [[claim-geobacter-conductive-filaments-are-omcs-cytochrome-polymers]]
- [[claim-lovley-2005-proposed-geobacter-nanowires-are-conductive-pili]]
- [[claim-geobacter-pili-are-secretory-pseudopili-not-nanowires]]
- [[claim-cable-bacteria-conduct-through-nickel-protein-wire]]
- [[claim-spectral-induced-polarization-detects-bacterial-cells-in-sand]] (geophysical detection of microbial electrical activity)

## Updates
- 2026-08-07: the Geobacter cytochrome-nanowire dispute now has a computed-physics prong — a Marcus-theory upper bound on redox-hopping current (~0.14 pA/filament) that the measured conductivities exceed by 10²–10⁵-fold, with the critic affirming the cytochrome identity and locating the open problem in the measurement technique ([[claim-guberman-pfeffer-0-14-pa-ceiling-is-computed-not-measured]], [[claim-guberman-pfeffer-blames-measurement-not-cytochrome-identity]]). New hub for the mechanism the dispute turns on: [[entity-redox-hopping]].