Biohybrid battery harvests energy from electric bacteria

Some bacteria are known to produce their own electricity, which could make them useful in batteries and fuel cells. But so far, attempts have been inefficient and inflexible. Now, researchers at Karlsruhe Institute of Technology (KIT) have created a “biohybrid” system built around a hydrogel that can support the microbes while effectively collecting their energy.

The bacteria at the heart of this system are known as exoelectrogens. This family of microbes can produce electrons, shuttle them across their outer membrane and then away from their cell. If we can catch these electrons, exoelectrogenic bacteria could essentially help build living batteries.

But there’s a delicate balancing act to this that previous attempts have struggled to strike. Conductive materials are needed to shunt the electrons to an electrode, but most of these aren’t great for bacteria to live on. Those that are more cosy for life, on the other hand, aren’t efficient conductors.