Vegetable oils serve as critical feedstocks for biofuels and bioproducts by providing energy-dense hydrocarbon molecules. Some plants have evolved divergent enzyme sets to produce high-value unusual fatty acids with novel chain lengths or functional groups.
A new study by researchers at the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI) aims to elucidate and harness an unusual fatty acid biosynthetic pathway in the seeds of Orychophragmus limprichtianus to expand the synthetic biology toolbox for plant- and microbe-based bioproducts.
Researchers conducted advanced lipid analyses using TLC, GC-MS and LC-MS to identify and characterize the previously unknown fatty acid composition in seeds of O. limprichtianus. They combined biochemical assays and molecular biology with AI-guided protein structure modeling to better understand the molecular mechanism of the biosynthetic pathway. The proposed biosynthetic pathway was reconstructed in an engineered oilseed host to validate enzyme function in vivo.
Two enzymes drive the pathway
Unusual fatty acids in O. limprichtianus seeds were identified as C24–C28 keto-hydroxy fatty acids. This distinct lipid profile is driven by two divergent enzymes: fatty acid elongase 1 (FAE1) and 3-ketoacyl-CoA reductase (KCR1).
These findings revealed a biosynthetic pathway in which the plant system has acquired bacterial polyketide synthase (PKS)-like discontinuous elongation functionality.
Reconstruction points to industrial use
This work reveals unprecedented evolutionary plasticity in plant lipid metabolism, breaking traditional boundaries of fatty acid engineering. The researchers successfully reconstructed this pathway in an engineered oilseed host, establishing a powerful synthetic biology toolkit to produce high-value oil. This work provides a scalable bio-based source for industrial lubricants, supporting the bioeconomy.