Production of 8,11‐cis‐eicosadienoic acid by a Δ5 and Δ12 desaturase‐defective mutant derived from the arachidonic acid‐producing fungus Mortierella alpina 1S‐4

Abstract

AbstractThe Δ5 and Δ12 desaturase (DS)‐blocked mutants of an arachidonic acid‐producing fungus, Mortierella alpina 1S‐4, were obtained. These mutants accumulated 8,11‐cis‐eicosadienoic acid (20:2n‐9). One of the mutants, M226‐9, in which Δ5 and Δ12 DS are perfectly blocked, produced 1.68 mg of 20:2n‐9 per mL of culture medium (101 mg/g dry mycelia) and no 5,8,11‐cis‐eicosatrienoic acid (20:3n‐9) when grown in a medium containing 4% glucose and 1% yeast extract at 28°C for 2 d and then at 12°C for 12 d. The mycelial lipid comprised 77.4% triacylglycerol (TG) and 9.8% phosphatidylcholine (PC), among others. TG contained 69.0% of the total 20:2n‐9, whose percentage in total TG fatty acids was 15.9%. The highest percentage (44.4%) of 20:2n‐9 was found in PC. The addition of olive oil to the culture medium enhanced the production of 20:2n‐9.