A new study by scientists at the American Chemical Society has identified an unlikely new source for raw materials for biodiesel fuels - butter.

Researchers report that butter could be used as an eco-friendly feedstock for diesel fuel, a possible new source beyond the current ethanol production.

As part of the study, researchers removed the fat from 250kg of butter, and converted it into the fatty acid esters that constitute biodiesel. The result material met all but one of the official test standards for biodiesel - suggesting that further purification or blending could produce a viable fuel.

The study, Butter as a Feedstock for Biodiesel Production, has been published in the ACS's bi-weekly Journal of Agricultural and Food Chemistry.

With the US government committing to more than triple production of biofuels to 36 billion gallons (136.2 billion litres) by 2022, new sources of biodiesel are likely to become valuable in the near future. While butter is not as efficient as plant-based sources in terms of resources for production, the research offers an opportunity to transform spoiled or surplus butter into a valuable resource.