Methane-eating archaea grow on electrodes and form conductive nanowires

Anaerobic methanotrophic archaea (ANME), which consume methane without oxygen, build electrically conductive nanowires and use them to pass electrons to an electrode. The finding comes from a team led by microbiologist Cornelia Welte at Radboud University and is reported in Nature Communications. The group also grew ANME so that they made up about 95% of the microbial community, which the researchers say had not been done before.

From electricity to nanowires

Welte's group reported four years ago that ANME can convert methane into an electrical current. How the organisms moved electrons to an outside surface remained unresolved. Other microorganisms were already known to form nanowires, but it was unclear whether ANME did the same.

The new work answers that question by imaging the archaea on an electrode with a specialised microscope. The paper, led by Martijn Wissink, describes the structure of nanowires of the OmcZ-type cytochrome class in these archaea. Cytochrome-based nanowires are best known from other electron-exporting microbes, so the result places ANME alongside them.

Faster growth on an electrode

In the laboratory, the microbes live in a small water-filled vessel and are supplied with methane. They attach to an electrode carrying a small voltage, multiply there and release electrons to it, producing a small current.

According to Welte, growth under these conditions is much quicker than in nature. Cells in ditches and trenches divide about once a month, whereas cells on the electrodes divide about once every five days. Such a speed-up matters because ANME are notoriously slow growers, which has long made them hard to study.

A near-pure culture

The second advance is the enrichment itself. Natural ANME communities are mixed, and the archaea usually grow alongside partner organisms. A culture in which 95% of cells are ANME lets researchers examine the organisms' biochemistry and electron transfer with far less interference from other microbes. Welte credits collaboration with several partners, among them researchers at Yale, for achieving this.

The source does not give the number of cultures or replicates, nor the methods used to measure community composition, so the robustness of the enrichment cannot be judged from the summary alone.

Applications remain distant

The current produced in the lab is small. Welte suggests it could one day drive hydrogen production. In principle, she says, microbes could turn methane into electrical energy with a small applied voltage far more efficiently than an electrolyser can. She puts any practical use at around 20 years away, and describes the present technique as too expensive and too complex for use outside the laboratory.

The team's own emphasis is on fundamental questions: how ANME work, how their nanowires are assembled, and how electrons move from methane oxidation to the electrode. ANME are also of interest in environmental microbiology because anaerobic methane oxidation in natural settings limits how much of this greenhouse gas escapes. A fast-growing, near-pure culture gives a controlled system in which those processes can be tested directly.

What comes next

Likely next steps include comparing the nanowires with those of other electroactive microbes, and testing how voltage and methane supply affect growth and current. Improving efficiency and lowering cost would be preconditions for any technological use. For now, the work provides both a structural explanation for ANME electron export and a laboratory system for studying it.

Source: Methane-eating microbes grown on electrodes build electrically conductive nanowires (Phys.org, 10 November 2026).

Image: AI-generated illustration.