Scientists from the University of Nevada (United States) have shown that biodiesel need not be produced from cultivated bioenergy crops, but also from waste raw materials, such as spend coffee grounds. Spent coffee grounds are solid waste materials from coffee brewing, and until recently, composting has been a common option for waste management. Scientists, Narasimharao Kondamudi, Susanta Mohapatra, and Mano Misra, found that the material still contains about 10% to 15% recoverable oil which can be used for biodiesel production. Aside from a projected stable supply of the waste for biodiesel conversion, the scientists also mentioned that the biodiesel product from spent coffee grounds would be “more stable than those from other sources because coffee contains antioxidants that would slow down degradation”. They were able to produce a biodiesel product with a 100% conversion efficiency of the extracted oil and with a stability lasting about one month under ambient conditions. About 340 million gallons of biodiesel can be reportedly produced from the waste coffee grounds around the world. The solid residue after oil extraction could also be used for “fertilizer, feedstock for ethanol, and as fuel pellets”. A publication of the research work appears in the Journal of Food and Agricultural Chemistry (URL above)..