"Right now, their fuel cell runs only on sugar cubes, since these produce almost no waste when broken down, but they aim to move on to carrot power," New Scientist magazine said this week.

Chris Melhuish and his team are using the cell to run a small light-sensitive robot but they said when a series of the cells are connected they could run domestic appliances.

The bacteria-driven cell, which would cost about 10 pounds ($15), directly converts biochemical energy into electricity. It uses E.coli bacteria to break down carbohydrates and release hydrogen atoms.

"The cell also contains chemicals that drive a series of redox, reduction and oxidation reactions, stripping electrons from the hydrogen atoms and delivering them steadily to the fuel cell's anode. This creates a voltage that can be used to power a circuit," the magazine said.