It could soon be possible to use bacteria to generate energy, following a discovery by scientists at the University of East Anglia.
The team has for the first time been able to determine the exact molecular structure of the proteins which enable bacterial cells to transfer electrical charge.
This means that if scientists can find ways to 'tether' bacteria directly to electrodes, it could be possible to create efficient microbial fuel cells or 'bio-batteries'.
"This is an exciting advance in our understanding of how some bacterial species move electrons from the inside to the outside of a cell," says Dr Tom Clarke of the university's School of Biological Sciences.
"Identifying the precise molecular structure of the key proteins involved in this process is a crucial step towards tapping into microbes as a viable future source of electricity."
Bacteria survive in oxygen-free environments by constructing electrical wires that extend through the cell wall and make contact with a mineral, in a process called iron respiration.
In this latest research, the scientists used a technique called x-ray crystallography to reveal the molecular structure of the proteins attached to the surface of a Shewanella oneidensis cell through which electrons are transferred.
The proteins act as an electric terminal on the outer surface of the bacterial cell. Analyzing their structure has allowed the team to understand how the bacteria transfer electric charge, both directly and via an 'electron shuttle' mechanism.
The team says the advance could also hasten the development of microbe-based agents that can clean up oil or uranium pollution, and fuel cells powered by human or animal waste.