4. Conclusions
This study demonstrated that spent coffee grounds can be used as raw material in a biorefinery to produce both biodiesel and ethanol. Oil from spent coffee grounds can be extracted ultrasound-assisted extraction yielding 12% of oil consisting mainly of palmitic and linoleic acids, and shows potential application for biodiesel production. The oil-free spent coffee grounds had potential application to produce carbohydrates for ethanol production by fermentation. The process resulted in a yield into ethanol of 0.50 gethanol gglucose−1 and a productivity of 1.9 g L−1 h−1.
Acknowledgements
The authors thank the Brazilian research agency CNPq for the financial support of this work and for the award of scholarships.