Significant progress has been achieved across all the objectives by the performance of several scientific activities, demonstrating the technical feasibility and sustainability potential of yeast-based pathways for SAF production.
Multiple biowaste streams—including agro-food residues, urban pruning waste, textile waste, and algal biomass—have been successfully processed into fermentable carbon sources. Sugar-rich media obtained from these biowastes proved suitable for the cultivation of NCY, while preliminary strategies were developed to convert challenging feedstocks, into short-chain fatty acid (SCFA)-rich media.
Substantial advances have been made in the development of NCY for SAF intermediate production. Key achievements include the establishment of advanced synthetic biology tools (e.g. CRISPRi/a multiplexing), adaptive laboratory evolution to enhance strain robustness, metabolic engineering of terpene pathways, and the optimisation of fermentation processes under industrially relevant and high-salinity conditions. These NCY platforms have been further validated at larger scales, with successful bioreactor fermentations and downstream recovery of triacylglycerols using different cell disruption and extraction strategies.
Advanced catalytic systems based on Ni, Ru, Mo, and W supported on zeolites have been developed and evaluated for the hydroconversion of yeast-derived fatty acids into SAF precursors. Complete experimental and analytical workflows have been established, and hydrocracking tests generated key performance data, enabling the assessment of process efficiency and integration at industrial scale.
Experimental data generated across have provided the basis for environmental, social, and techno-economic assessments. In addition, a comprehensive literature review identified key challenges related to industrialisation, scalability, and sustainability, supporting the development of realistic and data-driven process models.
Finally, the broader societal and environmental implications of the proposed technologies have started to be addressed. The valorisation of biowaste streams and the development of efficient yeast-based SAF production routes contribute to GHG emission reduction, circular economy principles, and reduced dependence on fossil fuels. Preliminary work on communication frameworks and social acceptance highlights the potential of these solutions to improve societal wellbeing while supporting cleaner energy systems.
