From waste biomass to bio-fuel: an innovative and sustainable approach to ethyl levulinate production

To date, the transport sector remains greatly reliant on fossil fuels. This dependence significantly contributes to atmospheric CO2 emissions and associated environmental impacts. In response, biofuels offer a sustainable and feasible alternative, being compatible with existing internal combustion engines. Among emerging biofuels, alkyl levulinates (ALs) have gained great attention, and, in particular, ethyl levulinate (EL), being fully renewable and already successfully employed as bio-blendstock in Diesel engines. This study explores the production of EL from two food supply chain wastes: thick juice (TJ), a low-value intermediate of sugar refining, and bread waste (BW), a widely available food residue. The use of wastes and their derivatives as feedstock is a key factor in enhancing both the sustainability and economic feasibility of large-scale biofuel production, in agreement with the circular economy approach. The one-pot acid-catalysed alcoholysis reaction was performed, using ethanol both as a reagent and solvent, and diluted H2SO4 as a cheap commercial homogeneous catalyst. Finally, the potential of EL as a gasoline bio-blendstock was experimentally evaluated using EL blends up to 10 vol%.