Imagine finding a live electrical wire in a pile of mud. Now imagine that wire is actually a bacterium. In the gray mud of Oregon's Yaquina Bay, a group of researchers has identified a microorganism that behaves just like an electrical conductor. TheElectrothrix yaqonensis, as the new species is called, not only transports electric charge, but it does so over distances that seemed impossible in the biological world. It may seem like a laboratory curiosity, but the implications of this discovery go far beyond that.
A living cable in the mud
Candidatus Electrothrix yaqonensis belongs to a very special group of bacteria. Unlike most microbes, which perform all their functions within a single cell, these bacteria operate as long chains of cells, filaments that extend up to several centimeters through the sediment. A huge size by microbial standards.
But this is just the tip of the iceberg of their oddities. In the deepest, oxygen-free layers of the mud, some cells “breathe” sulfides, extracting electrons from them. At the surface, just below the water, other cells complete the process by passing those electrons to oxygen. The entire filament functions much like an electrical cable, connecting the anaerobic chemistry of the depths to the oxygen reactions at the surface.
“Electric Cable Bacteria”: An Electrifying Discovery
The team of microbiologists led by Cheng Li e Clare Reimers ofOregon state university discovered this species in 2019, hidden in the sediments of Yaquina Bay. Researchers spent 14 months isolating and growing this bizarre, hollow bacterium in the laboratory. And the effort paid off.
The team managed to extract a complete genome and characterize the organism, from cell shape to electron flow. Genetically, YB6 (the lab code name) is unique, distinct enough to deserve its own name, chosen in honor of the Yako'n people, the indigenous tribe whose ancestral lands include Yaquina Bay.
“Naming an ecologically important bacterium after a tribe recognizes its historic connection to the land and recognizes its ongoing contributions to ecological knowledge and sustainability,” she explained. Cheng Li.
A unique biological conductor
Under the microscope, the filaments of this bacterium show the characteristic external ridges of cable bacteria. It has conductive fibers that carry electricity, but they are unusually large, up to three times larger than those of known species. And unlike the straight crests of its relatives, YB6's curls into a helical twist.
When the researchers measured electrical currents by placing YB6 filaments on gold electrodes, the results were surprising: under a gentle voltage, the filaments conducted currents at the microampere level. Not enough to power your phone, but a huge amount of energy at the microbial level.
Potential applications of the biological electrical cable
The discovery of Ca. electrothrix yaqonensis is, first and foremost, a remarkable biological curiosity. It exemplifies how life evolved complex behaviors such as long-distance cellular cooperation without nerves, brains, or limbs. It also suggests how much microbial diversity we are still missing.
But there is also the fascinating possibility of actually using these bacteria in bioelectrochemical processes. In other words, researchers wonder whether we could exploit their natural conductive ability.
Imagine using biology to grow electrical wires instead of melting copper. Or using bacteria to self-assemble underground conductive networks. Or using them as natural sensors for water quality and pollution. These are just a few of the avenues scientists are considering.
For now, YB6 remains a thread in a larger picture of microbial electricity that we’re only just beginning to understand. The mud beneath our feet is more “wired” than we thought. As the research team has shown, if you want to uncover nature’s hidden electricians, sometimes you just have to get your hands dirty.
A systematic review was published in the magazine Applied and Environmental Microbiology.
