Faeces could be used to power a future generation of mobile phones, scientists have said.
Researchers have found a natural process which occurs within bacteria that could help improve "bio batteries".
It is hoped the discovery could produce energy for portable technology, such as mobiles, tablets and laptops.
The study from the University of East Anglia (UEA) focused on how electrons cross bacterial proteins.
Both human and animal waste contain bacteria which breathe minerals of iron much like we breathe oxygen.
An electrical charge is released during this "breathing" process.
This is released from the cell, similar to the neutral wire in a household plug, and can then be harnessed.
Lead researcher Julea Butt, from the University of East Anglia's schools of chemistry and biological sciences, said: "These bacteria can generate electricity in the right environment.
"This is an exciting advance in our understanding of how some bacterial species move electrons from the inside to the outside of a cell and helps us understand their behaviour as robust electron transfer modules.
"We hope that understanding how this natural process works will inspire the design of bespoke proteins which will underpin microbial fuel cells for sustainable energy production."