In 1987, biologist Derek Lovley discovered a new species of bacteria, later named Geobacter metallireducens, in the muddy shallows of the Potomac River, Washington DC. Now, 21 years and 230 research papers later, Lovley is still fascinated by his discovery. In fact, he's built a career around it, because the Geobacter species have an intriguing and potentially useful characteristic: they can generate electricity. Lovley and his team have already built microbial fuel cells powered by Geobacter. They don't produce much electricity enough to power children's toys - but they run continuously on a simple solution of organic material. Lovely, who is Professor of Microbiology at the University of Massachusetts, believes microbial fuel cells could have applications ranging from implanted medical devices to powering sewage treatment plants.