BBC News reports Sony has presented a prototype of a battery that turns shredded paper into sugar which in turn is used as fuel:
The Japanese electronics giant showed off its invention at the Eco-Products exhibition in Tokyo last week.
Employees invited children to drop piece of paper and cardboard into a liquid made up of water and enzymes, and then to shake it. The equipment was connected to a small fan which began spinning a few minutes later.
The process works by using the enzyme cellulase to decompose the materials into glucose sugar. These were then combined with oxygen and further enzymes which turned the material into electrons and hydrogen ions.
The electrons were used by the battery to generate electricity. Water and the acid gluconolactone, which is commonly used in cosmetics, were created as by-products.