LONDON (TIP): Bio-batteries have now taken a giant leap towards becoming a reality. British scientists have made an important breakthrough in the quest to generate clean electricity from bacteria.

Findings published today show that proteins on the surface of the bacteria can produce an electric current by simply touching a mineral surface.

The study has therefore found for the first time 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.

This means that it is possible to tether bacteria directly to electrodes – bringing scientists a step closer to creating efficient microbial fuel cells or bio-batteries. Researchers from the University of East Anglia are working with a marine bacteria called Shewanella oneidensis.

They created a synthetic version of this 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 small capsules of lipid membranes such as the ones that make up a bacterial membrane.

Then they tested how well electrons travelled between an electron donor on the inside and an ironbearing mineral on the outside. Lead researcher Dr Tom Clarke 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 was not been clear whether these proteins do this directly or indirectly through 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.

This is the first time that we have been able to actually look at how the components of a bacterial cell membrane are able to interact with different substances, and understand how differences in metal and mineral interactions can occur on the surface of a cell.” Dr Clarke added “These bacteria show great potential as microbial fuel cells, where electricity can be generated from the breakdown of domestic or agricultural waste products.

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.”