Researchers have identified a new species of cable bacterium, Candidatus Electrothrix yaqonensis, that conducts electricity with the efficiency of a copper wire. Unearthed in the intertidal mudflats along Oregon’s coast, this microorganism represents a significant advance in the emerging field of bioelectronics—and could pave the way for novel biotechnologies ranging from environmental remediation to biosensors.
Honoring First Nations Heritage
The bacterium’s name pays tribute to the Yaqo’n people, the local First Nations community whose ancestral lands border the estuarine zones where the mud samples were collected. “We wanted to acknowledge the traditional stewards of this ecosystem,” explained microbiologist Cheng Li, who holds joint appointments at Oregon State University and James Madison University.
Cable Bacteria: Nature’s Living Wires
Cable bacteria comprise a remarkable group of filamentous microorganisms that form multicellular chains capable of long-distance electron transport. First described in 2012, they fall into two candidate genera—Electrothrix and Electronema—neither of which has been successfully cultured in isolation. These microbes thrive at the interface between oxygen-rich and oxygen-poor sediments, connecting redox reactions across centimeters of otherwise inert mud.
“Cable bacteria are nature’s electrical grid beneath our feet,” said Li. “By linking sulfide-oxidizing cells deep in the anoxic layer to oxygen-reducing cells near the surface, they achieve a division of labor that no single microbe could manage alone.”
A Bridge between Genera
What makes Ca. Electrothrix yaqonensis stand out is its genetic and morphological hybridity. Phylogenomic analyses reveal that it occupies an early branching point within the Electrothrix clade, sharing traits with both established cable-bacteria genera. “It’s a bridge species, offering clues to the evolutionary steps that gave rise to long-distance electron transport,” noted lead researcher Anwar Hiralal of the University of Antwerp.
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Pronounced Surface Ridges and Nickel Fibers
Under electron microscopy, C. E. yaqonensis exhibits pronounced surface ridges up to three times wider than those of its cable-bacterium cousins. These ridges encase an intricate network of conductive fibers, composed of unique nickel-based metalloproteins. Spectroscopic characterization confirmed the presence of nickel cofactors—a feature that sets this species apart from others known to rely on sulfur or iron for conductivity.
“These nickel-containing fibers are akin to nature’s coaxial cables,” said Hiralal. “Their molecular architecture may inspire synthetic analogues for bioelectronic applications.”
How Electric Conduction Works
In situ, buried cells oxidize hydrogen sulfide (H₂S) to generate electrons. These electrons travel along the exopolysaccharide sheaths and conductive fibers to surface cells, which reduce oxygen (O₂) or nitrate (NO₃⁻) in the overlying water. This metabolic partnership enables cable bacteria to thrive in sulfidic sediments where most aerobic microorganisms cannot survive.
- Deep Sediment Cells: Oxidize sulfide → generate electrons.
- Conductive Filament Network: Transports electrons across distances of up to several centimeters.
- Surface Cells: Reduce oxygen or nitrate → complete the electrical circuit.
Environmental and Technological Implications
The discovery of Ca. Electrothrix yaqonensis carries profound implications for both ecology and engineering. In natural settings, cable bacteria influence sediment geochemistry, contributing to nutrient cycling, mineral deposition, and pH stabilization. Their electrical activity can accelerate the breakdown of organic matter and immobilize heavy metals, thereby shaping benthic ecosystems.
From an applied perspective, these microbes could serve as living catalysts in bioelectrochemical systems:
- Bioremediation: Deploy cable bacteria in contaminated sediments to detoxify pollutants through redox reactions mediated by electron transfer.
- Bioelectric Sensors: Harness the conductive filaments to develop low-cost, self-assembling electrodes for detecting toxins or metabolic byproducts.
- Sustainable Energy: Integrate bacterial wires into microbial fuel cells to boost power output and efficiency.
“Nature has evolved these nano-scale conductors over millions of years,” said Li. “By studying their structure and genetics, we can reverse-engineer new materials that out-perform current synthetic conductors in certain contexts.”
Collaborative, Interdisciplinary Research
The research team combined genomic, morphological, spectroscopic, and electrical assays to characterize the new species. Key contributors included Dr. Alexander Power and Dr. Tom Haines (Computer Science, Oregon State University), Dr. Tom Freeman (Psychology, OSU), and a cohort of life-sciences specialists: Matthew Gardner, Dr. Gyles Cozier, Peter Sunderland, Professor Stephen Husbands, Dr. Ian Blagbrough and Dr. Rachael Andrews. External collaborators spanned the University of Bristol, King’s College London, the Leverhulme Research Centre for Forensic Science (University of Dundee), Manchester Metropolitan University, Teesside University, and the University of Glasgow.
Insights into Evolutionary Dynamics
Beyond its practical applications, C. E. yaqonensis offers a window into the evolutionary pressures that shaped the cable-bacterium lineage. Its hybrid genome suggests that early ancestors may have experimented with different metal cofactors—nickel, iron, sulfur—before settling on the conductive fibers seen in modern species. Comparative genomics will help resolve whether nickel-based conduction emerged once or multiple times independently.
“The non-conformist metabolic traits of C. E. yaqonensis highlight the rich evolutionary tapestry within cable bacteria,” the authors write in their Nature paper.
Future Directions and Challenges
Although the prototype analyses have been illuminating, several obstacles remain:
- Cultivation: No cable bacterium has yet been isolated in pure culture. Overcoming this barrier would enable controlled laboratory experiments on physiology and biofilm formation.
- Genetic Editing: Developing genetic tools to manipulate cable-bacterium genomes would accelerate functional studies of conductive proteins and metabolic pathways.
- Scale-Up: Engineering bioreactors that support dense, conductive biofilms is essential for translating lab discoveries into industrial processes.
The team plans to refine phylogenetic placement by sequencing additional environmental strains and exploring mudflats in diverse geographic regions. They also aim to collaborate with materials scientists and electrical engineers to prototype bioelectronic devices incorporating nickel-based fibers.
Broader Ecological Significance
Cable bacteria have been detected in marine, estuarine, and freshwater sediments worldwide—from European fjords to Southeast Asian rice paddies. Their ubiquity underscores a fundamental role in sedimentary biogeochemistry. By accelerating sulfide oxidation and oxygen reduction, these microbes create microzones of acidity and alkalinity that influence the solubility of metals and the availability of nutrients for other organisms.
“Cable bacteria are ecosystem engineers,” said Hiralal. “Understanding their distribution and activity is critical for modeling sedimentary environments under changing climate conditions.”
Toward a New Era of Bioelectronics
The convergence of microbiology, materials science, and electrical engineering heralds an exciting chapter in bioelectronics. Cable bacteria exemplify how life can evolve solutions to conduct electricity at ambient temperatures, neutral pH and under anoxic conditions—regimes in which conventional metals and semiconductors often underperform.
- Biocompatible Sensors: Embedding bacterial wires within living tissues to monitor physiological parameters in real time.
- Self-Healing Circuits: Leveraging microbial growth to repair damaged conductive pathways in soft electronics.
- Green Computing: Exploring microbial circuits as components in low-power, biodegradable computing devices.
“We’re only scratching the surface of what biological conductors can do,” said Li. “Ca. Electrothrix yaqonensis is a demonstration of nature’s ingenuity—and a challenge to us to think beyond silicon.”
Conclusion: Nature’s Blueprint for Innovation
The discovery of Candidatus Electrothrix yaqonensis underscores the untapped potential of microbial life to solve pressing technological and environmental problems. By illuminating the genetic, structural and biochemical foundations of biological electron transport, researchers are laying the groundwork for sustainable, bio-inspired devices that could redefine electronics, energy and environmental remediation. As investigations continue, these mudflat-dwelling bacteria may well wire the future of bioelectric innovation.
