SCIENCE - A shocking diet: Researchers describe microbe that 'eats' electricity

A team of Harvard researchers showed that the commonly found bacterium Rhodopseudomonas palustris can use natural conductivity to pull electrons from minerals located remotely in soil and sediment while remaining at the surface, where they absorb the sunlight needed to produce energy ...

http://phys.org/news/2014-03-diet-microbe-electricity.htm