Isoprenoid fatty acids in antarctic krill (Euphausia superba)

In an attempt to elucidate the origin of phytanic (3,7,11,15‐tetramethylhexadecanoic), pristanic (2,6,10,14‐tetramethylpentadecanoic) and 4,8,12‐trimethyltridecanoic acids found in small quantities in whales, the fatty acid composition of the lipids from Antarctic krill ( Euphausia superba Dana) was determined by gas‐liquid chromatography. Phytanic acid was found to be present to the extent of 1·4% of the total fatty acids, and was isolated and identified by mass and infra‐red spectrometry. Two other isoprenoid fatty acids, pristanic acid (0·04%) and 4,8,12‐trimethyltridecanoic acid (0·05%) were detected by gas‐liquid chromatography. E. superba constitute almost exclusively the diet of whales inhabiting Antarctic waters, and the phytanic acid in whale oils is probably derived from ingested krill which presumably biosynthesise this acid from the phytol moiety of chlorophyll present in the diatoms on which these planktonic crustaceans live.