Abstract:

To increase the production of arachidonic acid (ARA)-rich oil, the effects of different pH and substrate feeding
strategies on the production of ARA by Mortierella alpina was studied. Three glucose-feeding strategies (one-time glucose
feeding, constant glucose feeding and pH feedback glucose feeding) in the fermentation process were designed and applied
to improve biomass, lipid yield and ARA content based on pH control. The results indicated that the growth of biomass was
promoted at pH 6.0 in the fermentation process, while the synthesis of fatty acids was benefited at pH 6.5. Compared with
two other feeding methods, the pH feedback method not only shortened the fermentation period to 160 h but also maximized
ARA productivity and yield to 1.32 g/(L·d) and 8.82 g/L, respectively.

Key words: Mortierella alpina, arachidonic acid, pH feedback, substrate feeding fermentation