Valorization of spent coffee grounds into biofuels and value-added products: Pathway towards integrated bio-refinery

• Published in: Fuel (Guildford) 2019-10, Vol.254, p.115640, Article 115640
• Main Authors: Atabani, A.E., Al-Muhtaseb, Ala'a H., Kumar, Gopalakrishnan, Saratale, Ganesh Dattatraya, Aslam, Muhammad, Khan, Hassnain Abbas, Said, Zafar, Mahmoud, Eyas
• Format: Article
• Language: English
• Subjects: Alternative energy sources; Bio-refinery; Bioactive compounds; Biodiesel fuels; Biofuels; Biogas; Biomass; Biorefineries; Byproducts; Coffee; Composts; Ethanol; Fuels; Landfills; Nanocomposites; Petroleum industry; Polymers; Purification; Recycling; Refineries; Refining; Reviews; Spent coffee grounds; Value-added products; Waste disposal
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2019.115640

[Display omitted] •Utilization of spent coffee grounds to biofuels and value-added products is presented.•Valorization of other coffee industry by-products to high-value refined products are suggested.•Potential of membrane technology for separation and purification of biofuels and value-added products is demonstrated.•Pathways towards SCG-integrated biorefinery scheme are proposed. Coffee is the second largest traded commodity after petroleum and the second most popular beverage after water. This big industry is believed to generate huge amount of waste with spent coffee grounds (SCGs) represents one of the main by-products. Recycling of such waste to fuels and value-added products through bio-refineries is a promising way to solve the problem of many countries that face daily challenges and heavy cost in waste disposal. This review aims to shadow the light on SCGs recycling potential in which over 230 published papers on SCGs recycling topic were gathered and discussed. Various opportunities to produce biofuels such as biodiesel, biogas, bioethanol, bio-oil and fuel pellets besides value-added products such as bioactive compounds, adsorbents, polymers, nanocomposites, and compost were discussed. Moreover, the potential of membrane technology related to various processes of biorefining, separation and purification in the proposed SCG-integrated biorefinery are presented. Based on the presented review, it is obvious that recycling of SCGs offers many worthwhile options to policymakers that can contribute towards huge financial saving on taxpayers of running and maintaining landfills besides saving the environment from harmful emissions. In conclusion, this review emphasizes that SCG-integrated biorefineries to produce different types of biofuels and value-added products are a very promising approach that shall be economically more scrutinized in the foreseen future.