In nature, says McMahon, photosynthetic bacteria effectively extract energy from their food — and microbial fuel cells capitalize on that efficiency. “By having the microbes strip the electrons out of the organic waste, and turning that into electricity, then we can make a process of conversion more efficient,” she says. “And they’re very good at doing that-much better than we are with our high-tech extraction methods.”

Through machinery such as plants, photosynthetic bacteria harvest solar energy. They also make products to power microbial fuel cells. “In many ways, this is the best of both worlds — generating electricity from a ‘free’ energy source like sunlight and removing wastes at the same time,” says Donohue. “The trick is to bring ideas from different disciplines to develop biorefineries and fuel cells that take advantage of the capabilities of photosynthetic bacteria.”

The benefit of using photosynthetic bacteria, he says, is that solar-powered microbial fuel cells can generate additional electricity when sunlight is available.