Oxford – A study conducted by the University of Pisa presents an innovative circular economy approach addressing two of today’s most pressing global challenges: the urgent transition to renewable energy sources and the growing issue of food waste. The research, published in the scientific publication Journal of Environmental Chemical Engineering, aims to transform bread waste – one of the most abundant food wastes worldwide (nearly one million tons per year) – into sustainable biofuel. Funded under the PNRR NEST project, the study stems from collaboration between the Department of Chemistry and Industrial Chemistry and the Department of Energy, Systems, Territory and Construction Engineering. For the first time, the research explores the sustainable synthesis of ethyl levulinate from waste bread – a high value-added bio-based compound already known for its applications in the chemical sector and as an oxygenated fuel additive. The researchers developed a simple, cost-effective process that can be easily scaled up for industrial application, using a low-cost catalyst – diluted sulfuric acid – and high initial biomass concentrations. This approach enables more concentrated product streams, reducing separation costs and improving overall process efficiency. Ethyl levulinate has already been widely studied as an oxygenated additive for diesel fuel. For the first time, however, the compound was also tested in gasoline engines, blended with commercial fuel at very high percentages – up to 40% by volume. Experimental tests showed that such blends do not significantly affect engine performance and require no modifications to existing internal combustion engines. On the contrary, the use of ethyl levulinate reduces pollutant emissions and decreases the share of fossil fuels in commercial fuels.