Advances in metabolic engineering for the production of sustainable aviation fuels

Sustainable aviation fuels (SAF) are critical for decarbonising the hard-to-abate aviation sector, which significantly contributes to global CO 2 emissions. Conventional SAF production routes, such as Hydroprocessed Esters and Fatty Acids, Fischer-Tropsch and Alcohol-to-Jet, offer drop-in compatibility but are constrained by feedstock availability, high costs and environmental impacts. This review highlights, as promising alternatives, microbial bioproduction via precision fermentation of SAF-relevant compounds from low-cost feedstocks, with reduced land use and enhanced circularity. Here, we focus on microbially derived SAF precursors such as alcohols, terpenes, fatty acid ethyl esters, methyl ketones and saturated hydrocarbons, as well as recent advances in host engineering, pathway design, and bioprocess optimisation.