Coffee is one of the most consumed beverages in the world, and as such around 8 million tonnes of spent coffee grounds (SCG) are produced globally every year. In the past, SCG were mostly considered as a waste or only used as compost, though SCG are a rich source of saccharides and lipids and recent research has focused on approaches that can reuse these SCG to produce biofuels and value chemicals. However, the lack of seasonal variation yet relatively low level of availability means that potentially the most advantageous use of the feedstock is through co-refining for the low supply of other types of biomass in certain periods throughout the year.<br/>In this project SCG is demonstrated to be comparable to other lignocellulosic biomass and therefore can be effectively used as a feedstock in an integrated biorefinery process producing a lignin/lipid based bio-oil, relatively pure cellulose and a fermentation broth. These fractions were upgraded into multiple products, including 5-HMF and furfural. Spent coffee grounds were then demonstrated to be a suitable blending feedstock by co-refining with <i>Scenedesmus acutus</i>. This process comprised pre-treatment of the biomass, fermentation of the resulting sugars, distillation and extraction. The coffee/algal oil obtained from extraction was demonstrated to be suitable for a range of different applications, such as the production of renewable diesel blend or non-isocyanate polyurethanes. Finally, a brief techno-economic analysis was conducted to assess what the potential cost of the resulting biofuels from this process would be.

Biorefinery to produce value chemicals and fuels from spent coffee grounds blended with microalgae

2019 Spring National Meeting

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