The "bio fuel cell" uses an anode coated with oxygen-tolerant hydrogenases—enzymes from a naturally occurring bacterium that oxidize hydrogen in its metabolism—coupled with a cathode modified with the fungal oxygen reductase, laccase. Laccase catalyses the reduction of oxygen to water.
The enzyme-coated electrodes are placed inside a container of ordinary air with 3% added hydrogen.
Prototype versions of the cell produced enough electricity to power a wristwatch and other electronic devices. Armstrong foresees advanced versions of the device as potential power sources for an array of other electronic products that only require low amounts of power.
The technology is immensely developable. We are at the tip of a large iceberg, with important consequences for the future, but there is still much to do before this generation of enzyme-based fuel cells becomes commercially viable.