Could bacteria be used to power our machines?

Researchers in America have taken some important steps towards creating a system in which bacteria do some mechanical work.This is tricky as bacteria tend to swim in random directions and each individual weighs almost nothing, so designing a system that can harness energy from them is a daunting challenge.

The researchers have now developed a set of microscopic gears that concentrate bacteria on only one side of each "gear tooth", causing the bacteria to pool at that edge and as they swim against it, they force the gear to turn in a single direction. Linking up two of these gears together, the bacteria were able to keep them spinning continuously for nearly two minutes.

This is incredibly impressive considering that each bacterium is millions of times less massive than one of these gears. In the future, it may be possible to create much larger devices that can extract more substantial amounts of energy.