They found it buried in the muddy shores of the Potomac River more than three decades ago: a strange “sediment organism” that could do things nobody had ever seen before in bacteria.
This unusual microbe, belonging to the Geobacter genus, was first noted for its ability to produce magnetite in the absence of oxygen, but with time scientists found it could make other things too, like bacterial nanowires that conduct electricity.
For years, researchers have been trying to figure out ways to usefully exploit that natural gift, and they might have just hit pay-dirt with a device they’re calling the Air-gen. According to the team, their device can create electricity out of… well, almost nothing.
“We are literally making electricity out of thin air,” says electrical engineer Jun Yao from the University of Massachusetts Amherst. “The Air-gen generates clean energy 24/7.”
The claim may sound like an overstatement, but a new study by Yao and his team describes how the air-powered generator can indeed create electricity with nothing but the presence of air around it. It’s all thanks to the electrically conductive protein nanowires produced by Geobacter (G. sulfurreducens, in this instance).
The Air-gen consists of a thin film of the protein nanowires measuring just 7 micrometres thick, positioned between two electrodes, but also exposed to the air.
Because of that exposure, the nanowire film is able to adsorb water vapour that exists in the atmosphere, enabling the device to generate a continuous electrical current conducted between the two electrodes.