Researchers make advance towards bio-batteries

The researchers have shown that it is possible for bacteria to lie directly on the surface of a metal or mineral and transfer electrical charge through their cell membranes - an advance which they claim could bring efficient microbial fuel cells or 'bio-batteries' a step closer to reality. The team began by creating a synthetic version of a common marine bacteria using just the proteins thought to shuttle the electrons from the inside of the microbe to the rock. They inserted these proteins into the lipid layers of vesicles, which are small capsules of lipid membranes such as the ones that make up a bacterial membrane. They then tested how well electrons travelled between an electron donor on the inside and an iron bearing mineral on the outside. Lead researcher Dr Tom Clarke, from UEA's school of Biological Sciences, said: "We knew that bacteria can transfer electricity into metals and minerals, and that the interaction depends on special proteins on the surface of the bacteria. But it has not been clear whether these proteins do this directly or indirectly though an unknown mediator in the environment. "Our research shows that these proteins can directly 'touch' the mineral surface and produce an electric current, meaning that is possible for the bacteria to lie on the surface of a metal or mineral and conduct electricity through their cell membranes. Dr Clarke believes the bacteria show great potential as microbial fuel cells. "Another possibility is to use these bacteria as miniature factories on the surface of an electrode, where chemicals reactions take place inside the cell using electrical power supplied by the electrode through these proteins," he concluded.