Air travel accounts for roughly 2.5% of global carbon dioxide emissions, and as passenger numbers continue to climb, the aviation industry faces mounting pressure to decarbonize without compromising efficiency.
Researchers at the University of Illinois Urbana-Champaign believe they may have found a viable solution: converting food waste into sustainable aviation fuel (SAF) that meets commercial standards—without blending with fossil fuels. Their findings, published in Nature Communications, introduce a process that could significantly reduce aviation’s carbon footprint while addressing one of the world’s largest waste problems.
At the core of the research lies hydrothermal liquefaction (HTL), a thermochemical process that uses heat and pressure to transform wet biomass—such as food scraps, sewage sludge, or agricultural residues—into a biocrude oil. This mimics the natural geological formation of fossil fuels but occurs within hours rather than millions of years. The resulting biocrude is then refined using hydrogen and a cobalt-molybdenum catalyst through catalytic hydrotreating, eliminating impurities such as nitrogen, oxygen, and sulfur to yield a hydrocarbon profile nearly identical to conventional jet fuel.
Lead researcher Sabrina Summers and her team demonstrated that the resulting SAF passed stringent ASTM and FAA certification benchmarks, including Tier Alpha and Beta prescreening tests, ensuring full compatibility with existing aviation engines and infrastructure. Unlike many biofuels that require blending, this SAF achieved compliance without fossil additives—a crucial step toward “drop-in” fuels capable of seamless adoption by airlines.
The feedstock flexibility of HTL technology strengthens its commercial potential. Globally, over 30% of all food produced is wasted each year, contributing heavily to methane emissions in landfills and inefficiencies across supply chains. By using discarded food from nearby processing facilities, the Illinois team showcased how local waste streams could be repurposed into high-value fuels. According to Professor Yuanhui Zhang, who led the study, “agriculture and biowaste will play a critical role in meeting the aviation industry’s decarbonization targets,” providing a consistent, renewable source of feedstock for SAF production.
Beyond aviation, the implications extend to the broader circular bioeconomy, which aims to recover energy and materials from waste streams. Zhang’s team developed a circularity index to quantify the process’s sustainability impact, arguing that transforming waste into energy closes a critical loop in today’s predominantly linear economic model.
While the technology remains at the research and pilot scale, its scalability potential could reshape both waste management and energy production.
