Production of 5,8,11-eicosatrienoic acid (Mead acid) by a Delta 6 desaturation activity-enhanced mutant derived from a Delta 12 desaturase-defective mutant of an arachidonic acid-producing fungus, Mortierella alpina 1S-4

Enhanced production of 5,8,11-eicosatrienoic acid CR (Mead acid, 20:3 omega 9) was attained by a mutant fungus, Mortierella alpina M209-7, derived from Delta 12 desaturase-defective M. alpina Mut48. The 20:3 omega 9 production by M209-7 was 1.3 times greater than that by its parent strain, Mut48. This is thought to be due to its enhanced Delta 6 desaturation activity, which was 1.4 times higher than that of Mut48. In both strains, 87 to 88% of the total lipids comprised triacylglycerol (TG) and 85% of 20:3 omega 9 was contained in TG. On optimization of the culture conditions for M209-7, earlier glucose feeding and shifting of the growth temperature from 28 to 19 degrees C on the second day were shown to be effective. Under the optimal conditions with a 10-liter jar fermentor, 20:3 omega 9 production reached 1.65 g/liter of culture medium (corresponding to 118 mg/g of dry mycelia and 28.9% of total fatty acids), which is about twice that reported previously (0.8 g/liter).