At the Eco-Products  2011 exhibition held last week at the International Exhibition Center in Tokyo, Sony offered “shreds of evidence” that paper can be used to fuel environmentally friendly bio-batteries.  If the bio-batteries are commercialized, the innovation could enable consumers to recharge their mobile devices using pieces of waste paper.

The prototype displayed by the electronics titan—developed by the Organic Electronics division of the company’s Advanced Materials Laboratories in Japan—generates electricity by turning shredded paper into sugar, which in turn is converted into fuel.

According to the BBC, the team behind the project said such bio-batteries use no hazardous chemicals or metals.

Sony 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—demonstrating that electricity was being generated.

Specifically, the process uses the enzyme cellulase to decompose paper into glucose sugar. Combined with oxygen and further enzymes, the glucose sugar is then converted into electrons and hydrogen ions.

The electrons generate the electricity. Water and the acid gluconolactone, which is commonly used in cosmetics, are created as by-products. Researchers compared the process to the one used by white ants and termites to digest wood and turn it into energy.

Their work builds on a previous project in which Sony used fruit juice to power a Walkman music player in August 2007.

“Using a ‘fuel’ as simple as old greetings cards —the sort of cards that millions of us will be receiving this Christmas—the bio-battery can deliver enough energy to power a small fan,” Yuichi Tokita, senior researcher at Sony’s Advanced Materials Laboratories, told the BBC.

“Of course, this is still at the very early stages of its development,” he said, “but when you imagine the possibilities that this technology could deliver, it becomes very exciting indeed.”

While the battery is already powerful enough to run basic music players, it is still falls far short of commercially sold batteries.