Regio- and enantioselective oxidation of thiaoleic acids by an algal Delta12-desaturase

In a non aerated incubation medium, the oxidation of the tested thiaoleic a cids by C. vulgaris was regioselective. Moreover the non oxidised 14-thiaol eic acid had no influence on the endogenous fatty acid pattern whereas the 13-thiaoleic acid, readily oxidised by the microalgae, caused a significant 18:1 accumulation in phospholipids. Examination of the 13-thiaoleic acid m etabolism revealed that up to 15% of the substrate was specifically oxidise d in the phospholipids before being transferred into the neutral lipids cla ss of C. vulgaris. Confirmation of the monooxygenase-like Delta 12-desatura se intervention in this biotransformation was obtained by the stereochemica l analysis of the optically active sulfoxide isolated from the endoplasmic phospholipids. (C) 1999 Elsevier Science Ltd. All rights reserved.