It’s the beverage that keeps on giving: not only can coffee keep drinkers awake but it might also prove a stimulant for the renewable fuel economy. Discarded coffee grounds can form the basis of a new biodiesel production method brewed up by an international research team.

This waste material contains nutrients that can support the cultivation of Chlorella vulgaris microalgae without the need for additional material inputs. The microalgae attach to and thrive on the surfaces of spent coffee grounds, building up the lipids, alkyl chains and other components that form biodiesel. The highest quality biodiesel was produced by exposing the algae to light for 20 hours a day and dark periods for just four hours.

Analysis indicates that the extracted biodiesel produces minimal emissions, good engine performance and meets U.S. and European specifications.

The researchers hail this caffeinated development, explaining: “Biodiesel from microalgae attached to spent coffee grounds could be an ideal choice for new feedstock commercialization, avoiding competition with food crops. Furthermore, using this new feedstock could decrease the cutting down of palm trees to extract oil to produce biofuel. In southeast Asia this has led to continuous deforestation and increased greenhouse gas emissions.”

The study conducted by scientists from Universiti Teknologi PETRONAS (Malaysia), Silpakorn University (Thailand), Chulalongkorn University (Thailand), Aston University (U.K.), Cape Peninsula University of Technology (South Africa), Tamkang University (Taiwan), Cairo University (Egypt), Jalan Universiti (Malaysia) and Saveetha Institute of Medical and Technical Sciences (India) is published in Renewable and Sustainable Energy Reviews.

To contact the author of this article, email shimmelstein@globalspec.com