Production of an eicosapentaenoic acid‐containing oil by a Δ12 desaturase‐defective mutant of Mortierella alpina 1S‐4

A Δ12 desaturase‐defective mutant of an arachidonic acid (AA)‐producing fungus, Mortierella alpina 1S‐4, converted α‐linolenic acid (18:3ω3) to 5 (Z) ,8 (Z) ,11 (Z) ,14 (Z) ,17 (Z) ‐eicosapentaenoic acid (EPA). On submerged cultivation at 20°C for 10 d in a 5‐L fermentor containing medium comprising 1% glucose, 1% yeast extract and 3% (vol/vol) linseed oil, EPA production amounted to ca. 1 g/L culture broth (64 mg/g dry mycelium), which accounted for ca. 20% of the total mycelial fatty acids. AA content was 26 mg/g dry mycelium (0.4 g/L), accounting for 7.8% of the total mycelial fatty acids. The other major mycelial fatty acids were palmitic acid (4.5%), oleic acid (20.4%), linoleic acid (10.0%), 18:3ω3 (20.3%) and lignoceric acid (4.3%). Most of the EPA produced ( ca. 90 mol%) was in triglyceride form.