Enzymatic Production of Sustainable Aviation Fuels from Waste Feedstock

The continuous fossil fuel exhaustion, as well as the increasing environmental challenges that are occurring globally, has underscored the need for research on alternative pathways of producing biofuels that will minimize aviation emissions over the next decades. The present review explores the employment of diverse waste sources as feedstock and enzymes as catalysts as environmentally friendly methods for producing sustainable aviation fuels (SAF). To achieve this goal, a comprehensive review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The results demonstrated that waste feedstocks catalyzed by enzymes represent an innovative alternative for SAF production. Specifically, the combination of enzymatic hydrolysis and microbial fermentation demonstrated considerable effectiveness in transforming complex waste feedstocks, such as lignocellulosic biomass, municipal solid waste, and food waste, into SAF precursors, including bio-isobutene and fatty acid methyl esters. Moreover, employing Chlorella variabilis fatty acid photodecarboxylase enzymes for photoenzymatic decarboxylation demonstrated significant conversion efficiency, particularly under gentle conditions, low energy consumption and remarkable selectivity. However, further research and development of the reviewed methods are necessary to enable the industrialization of these technologies.