The Bacterium That Breathes Metal
- DHRUVI GOHIL
- Aug 24
- 2 min read
When we think about breathing, we picture lungs filling with air, oxygen nourishing our cells. But not all life plays by our rules. Deep underground, in oxygen-starved mud and rock, there are bacteria that do something extraordinary: they breathe metal.
Wait — bacteria can breathe metal?
Yes. Certain microbes, like Shewanella oneidensis and Geobacter metallireducens, survive without oxygen by using metals such as iron or manganese as “electron acceptors.” Shewanella species are aquatic bacteria often found in deep sediments.
In simple terms, they move electrons out of their cells onto metal compounds — a bit like plugging themselves into a battery. Instead of exhaling carbon dioxide like we do, they deposit rust! Geobacter species, commonly found in soil and groundwater, take this process a step further by forming conductive pili protein filaments nicknamed nanowires.
Photo credit-asknature.org
How does it actually work?
-Normal respiration: Humans move electrons onto oxygen to release energy.
-Metal-breathing bacteria: These microbes move electrons onto solid metals.
-They have special proteins on their outer membranes — molecular “wires” that pass electrons along.
-The result? Energy to live, grow, and divide — no oxygen required.
Nature’s tiny electrician.
Why does this matter?
1. Cleaning pollution: These bacteria can reduce toxic metals like uranium, making contaminated groundwater safer.
2. Making electricity: Scientists have built “microbial fuel cells” where these microbes literally generate a current as they “breathe.”
3. Searching for life: If life can survive deep underground by breathing metal, similar life could exist on Mars or Europa — places without much oxygen but plenty of minerals.
On Mars, iron-rich dust and rocks could serve as their energy sinks, while on Europa, buried beneath an icy crust, they might tap into mineral deposits at the seafloor.
Nature’s hidden electrician
It’s wild to think about — while we gasp for air, some microbes are happily “exhaling” rust or even powering tiny circuits. These creatures remind us that life is incredibly adaptable, finding a way in places we would never expect.
The Rifle Aquifer in Colorado, USA, is rich in iron oxides and renowned for bioremediation studies using metal-breathing bacteria.
Next time you see rust on a bridge or a pipe, consider this: somewhere in the Earth, there may be a bacterium that treats iron oxide not as decay, but as breath.
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