A cow's stomach could hold the key to creating more environmentally friendly versions of petrol and diesel, according to Edinburgh scientists.
Researchers are investigating how enzymes found in the stomachs of cattle and other ruminants, animals which "chew cud", could be used industrially.
The plan being to break down the tough structures of plant and tree matter.
The discovery and application of the enzymes could release untapped energy in waste plant products to make fuel.
The study is being carried out by ARK-Genomics at Edinburgh's Roslin Institute, life sciences company Ingenza and Professor John Wallace from the Rowett Institute in Aberdeen.
Humans cannot digest the tough material which makes up plants and trees but Ingenza and Prof Wallace said they expected to identify the enzymes in ruminants which allow for the breakdown of these structures.
The scientists said the resulting chemical reactions could be used to create sustainable alternatives to petrochemical-derived products such as fuel, commodity chemicals and fine chemicals.
Dr Ian Fotheringham, president of Ingenza, said: "People have been trying to unlock the energy in plant and tree matter for years but our approach recognises how nature has already successfully done it.
"If we can identify novel enzymes that allow ruminants to break down these tough structures, and then replicate them on a large scale, the possibilities for more sustainable and renewable industrial practices are enormous.
"Society is starting to look towards how greener practices can contribute to economic growth and more sustainable living in a meaningful way. This project could be a real step towards that."
On 4 August, Professor Wallace will give a presentation on the science behind the idea at a technology event in Edinburgh organised by the Scottish Agricultural College, which will bring together the best of Scottish research, technology and collaboration projects.