Gondoic acid (cis-11-eicosenoic acid, 20:1Δ11) is an uncommon 20-carbon fatty acid that is a component of the seed oil of a small number of plant species. This fatty acid is a potential renewable feedstock for the polymer industry representing a source of C12 monomers through metathesis, or C11 monomers through reductive ozonolysis. Camelina sativa is the only oilseed crop that produces significant levels of gondoic acid, but at 13-15% of total seed fatty acids, camelina seed oil is not a commercially viable source of this fatty acid.
To identify new sources of gondoic acid, a survey of seed oil composition by GC and GC/MS was conducted for diverse plant species. Oils containing up to 46% gondoic acid were identified, often with additional very-long-chain fatty acids present. Further investigation of the oils by NMR, TLC and MALDI-TOF MS revealed novel storage lipids, including acetyl-TAG and cyanolipids, and oils with unusual fatty acid positional distribution. Oils containing gondoic acid from members of the Ranunculaceae were unusual in that the fatty acid was not accompanied by significant amounts of erucic acid (cis-13-docosenoic acid, 22:1Δ13). Developing seeds from two species were collected and transcriptome analysis enabled the identification of a novel pathway for gondoic acid biosynthesis. cDNAs encoding the enzymes for fatty acid elongation and incorporation into TAG were cloned and ectopically expressed in Camelina. Prototype plants showed a modest increase in seed gondoic acid levels. Characterization of these plants is suggesting new ways to increase gondoic acid levels in camelina seed oil.
.jpg "Mark A. Smith, PhD photo")