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A growing body of scientific work is revealing a remarkable feature of certain microbes. They can “breathe” in a way that produces electricity instead of relying on oxygen, suggesting unusual survival strategies that could inspire future clean energy solutions.

This discovery came to light when researchers noticed that some bacteria thrive in conditions with little or no oxygen by sending out electrons into their environment.

Soon after, they found a key detail: these bacteria hand off electrons through certain molecular carriers, enabling them to keep growing while essentially “exhaling” electric current. Caroline Ajo-Franklin of Rice University helped guide this project.

Bacteria produce electricity

Some species, including Shewanella and Geobacter, have long been known to transfer electrons to external surfaces, even metal oxides, while growing in oxygen-limited zones.

Scientists realized these organisms produce a small but steady electric current through this process.

Biki Bapi Kundu is a Rice doctoral student and first author of the study who took a closer look at an everyday bacterium and figured out the mechanism behind its power output. 

“This newly discovered mechanism of respiration is a simple and ingenious way to get the job done,” said Bapi Kundu.

Microbes generate energy without oxygen

These electricity-generating microbes do not rely on the usual electron acceptors, like oxygen. Instead, they latch onto conductive surfaces.

By pushing electrons onto external materials, they gain energy to keep going in oxygen-deprived spots.

Researchers now know that certain bacteria use a special molecule known as naphthoquinone to help pass electrons to their outside world.

Once those electrons move out, the cells generate energy in a self-sustained system. The process bears similarities to how a battery releases current.

Microbes transfer electrons like a battery

These bacteria gain an advantage by freeing up electrons they would otherwise hold onto. Through that exit pathway, they can break down carbon sources more efficiently than in standard fermentation processes.

It seems that this feature might be lurking in a wider range of microbes than previously thought. One research group discovered that these electricity-making strategies are not limited to organisms specifically adapted to extreme habitats.

“Our research not only solves a long-standing scientific mystery, but it also points to a new and potentially widespread survival strategy in nature,” said Ajo-Franklin.

Uses for electricity-producing bacteria

Because electricity-producing bacteria can relieve the buildup of electrons, they have potential uses in various industrial applications.

Some scientists foresee improved wastewater treatment, where these microbes might help remove pollutants while sending out an electric signal.

This line of work could also help with biomanufacturing. While certain processes bog down from electron imbalances, electricity-generating organisms might balance the system by shuttling electrons away in real time.

Long-term vision for clean energy

With a bit of engineering, these cells might even harness carbon dioxide through renewable power. The concept mimics photosynthesis in plants, but here, bacteria could rely on external electricity in a controlled setting.

In the future, we may see specialized microbial communities that maintain their own flow of electrons, feeding into sensors and energy devices.

Researchers note that these bacteria may also prove handy in areas where oxygen is scarce, like underground or potentially even in space technology.

Bacteria as real-time sensors

Experts believe electricity-making cells could bring improvements to environmental monitoring. Their electrical signals change when toxins are present, so they can provide real-time alerts about pollution or water quality.

Some hope that such systems might open the door to new diagnostic tools as well. The natural inclination of these microbes to shuttle electrons might allow them to perform tasks that previously demanded more complex instruments.

What does all of this mean?

These findings expand our perspective on microbial metabolism. Once thought to be limited to fermentation under oxygen-free conditions, many ordinary bacteria may hold hidden skills for electron transfer.

The implications extend across fields from bioengineering to synthetic biology. Researchers are optimistic that this work will encourage a deeper examination of how microbes manage energy in their native habitats.

By understanding these strategies, scientists can look for ways to steer or optimize electron transfer on a larger scale.

Academics point out that an improved knowledge of microbial electron flow could open new doors in sustainable technology.

If cultivated in controlled bioreactors, these organisms might help curtail industrial waste and boost the output of valuable chemicals.

At the same time, study authors are cautious about the next steps. They say that scaling up these systems requires more data and design know-how, but they remain confident about the future.

The study is published in the journal Cell.

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