Imagine a phone that charges itself using living bacteria. It sounds like science fiction, but researchers at Rice University say it could become reality.
A new study in the journal Cell describes bacteria that “breathe” electricity instead of oxygen. These microbes use natural compounds called naphthoquinones to transfer electrons outside their cells – a process known as extracellular respiration. It allows them to generate energy by discharging electrons onto external surfaces, not unlike a battery.
Although scientists have observed and used this type of respiration in biotechnology for years, its underlying process has remained unclear. The new research uncovers how it works and suggests it may be more widespread in nature than once thought.
“Naphthoquinones act like molecular couriers,” said lead author Biki Bapi Kundu. “They carry electrons out of the cell, allowing the bacteria to break down food and survive without oxygen.”
The Rice team partnered with the Palsson lab at the University of California, San Diego, to test the discovery. The researchers used advanced computer models to simulate bacterial growth in oxygen-free environments with conductive surfaces. The models showed that bacteria could survive by releasing electrons externally. Lab experiments confirmed the prediction: bacteria grew and generated electricity on conductive materials, essentially “breathing” through the surface.
Lead researcher Caroline Ajo-Franklin called the finding “a clever trick nature uses to survive.” She envisions future uses in places where traditional batteries fall short – like wastewater treatment plants that use bacteria to produce electricity and clean water, or Mars rovers powered by microbial reactors instead of heavy batteries.
While the current power output is small – enough for a sensor, not a smartphone – scientists hope to boost it by engineering stronger bacterial strains and exploring new conductive materials.