Scientists have discovered how a particular type of bacteria transfers electricity, a finding that they say will help them develop fully biological batteries. Scientists previously knew that the bacteria, shewanella oneidensis, attaches to rusty iron and other materials and breaks them down, transferring electrons in the process. But researchers weren't sure just how the bacteria managed to do this, so they created a synthetic version in the lab and tested it against iron.

"These bacteria show great potential as microbial fuel cells."

They found that proteins on the surface of the bacteria were responsible for the electron transfer, which means that they could potentially be used as parts of a battery or as a power source. “These bacteria show great potential as microbial fuel cells, where electricity can be generated from the breakdown of domestic or agricultural waste products," said Tom Clarke, a researcher at the University of East Anglia in the UK who led the study, which was also funded by the US Department of Energy. Microbial fuel cells are systems that try to tweak the metabolism of certain types of bacteria to make them generate more usable energy than they normally would. In this case, the bacteria is found at the bottom of bodies of water around the world.

The results were published in the journal Proceedings of the National Academy of Sciences this week. Clarke and his colleagues have been studying this bacteria for use in microbial fuel cells for years now, so while the new finding adds to their growing body of research, it doesn't necessarily mean a bio-battery is on the horizon for the near term.