A Study on New Nitrogen Source for Cultivation of Genus Mortierella

Potato-dextrose-agar plates are widely used as stock culture medium. While screening fungus producing highly unsaturated fatty acids, many different filamentous fungi, such as genus Mortierella, were found to grow best in the medium containing potato extract and accumulate lipids present at 35% dry cell weight. Potato protein powder is now available commercially and thus was used into present study as the solid and liquid medium cultivation of Mortierella alpina in place of potato extract. But this brought about no significant change in morphology and harvest in either case. Optimum concentrations of potato protein powder were 0.25-0.50% and 1.0-2.0% for the two media respectively. A comparison of lipid content of the fungus in the liquid medium with that of the fungus in the soy flour-dextrose liquid medium indicated use of the potato protein powder to have resulted in 50-100% more lipid production by the fungus. Examination of the various components of the media indicated amino acid composition, or other substances to possibly have been factor for this.