Direct hydroxylation in the biosynthesis of hydroxy fatty acid in lipid a of Pseudomonas ovalis.

It was found that Pseudomonas ovalis IAM 1177 had an abundance of hydroxy fatty acids such as 3-hydroxy-decanoic acid, 3-hydroxy-dodecanoic acid and 2-hydroxy-dodecanoic acid in the lipophilic part of the lipopolysaccharide fraction, which comprise 80% of total fatty acids. By using 18O2, it was shown that one oxygen atom from molecular oxygen was incorporated into 2-hydroxy-dodecanoic acid, but not into 3-hydroxy-decanoic acid. The incorporated oxygen atom was specifically located at the hydroxyl group of 2-hydroxy-dodecanoic acid. The biosynthetic pathways of these hydroxy fatty acids are discussed.