Production of 5,8,11-eicosatrienoic acid (Mead acid) by a Δ6 desaturation activity-enhanced mutant derived from a Δ12 desaturase- defective mutant of an arachidonic acid-producing fungus, Mortierella alpina 1S-4

Abstract

Enhanced production of 5,8,11-eicosatrienoic acid (Mead acid, 20:3ω9) was attained by a mutant fungus, Mortierella alpina M209-7, derived from Δ12 desaturase-defective M. alpina Mut48. The 20:3ω9 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 Δ6 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 20:3ω9 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°C on the second day were shown to be effective. Under the optimal conditions with a 10-liter jar fermentor, 20:3ω9 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).