Coffee grounds identified as viable feedstock for biodiesel production

Researchers at the University Rovira i Virgili (URV) have demonstrated that used coffee grounds, which contain about 15% lipids, can be efficiently processed into biodiesel feedstock. In experiments published in the journal *Biomass and Bioenergy*, the team optimized oil extraction using n‑hexane under conditions of 45 °C for 60 minutes with a solvent ratio of 35 ml per gram of dry residue, achieving roughly 90% recovery of oil and a low impurity level of 0.3% compared with the 3.9% obtained by conventional Soxhlet extraction. The extracted oil is rich in linoleic and palmitic acids, making it suitable for biodiesel production.

The study also found that removing the oil does not impair the remaining solid material, which can be further converted into bioethanol, lactic acid, biodegradable plastics, or other bio‑fuels, supporting circular‑economy approaches for sectors such as heavy transport that are difficult to electrify.