Effects of Metal Ion Concentrations on Lipid and Gamma Linolenic Acid Production by Cunninghamella sp. 2A1

The effects of different concentration of MgSO₄.7H₂O, FeCl₃.6H₂O, ZnSO₄.7H₂O, CuSO₄.5H₂O and MnSO₄.5H₂O on lipid and GLA production by Cunninghamella sp. 2A1 were studied in submerged culture fermentation. Cultivation was performed in 250 ml conical flask (100ml working volume), at 30°C and 250 rpm agitation for 120h. Mg²⁺, Fe²⁺ and Zn²⁺ have significant effect on lipid accumulation as inclusion of each ions resulted in a 64, 43 and 33% increase in lipid content compared to cultures which was cultivated with the omission of each ions, respectively. All three metal ions also affected GLA production by Cunninghamella sp. 2A1 with Zn²⁺ having the most profound effect with an increase of up to 74% of GLA yield (g GLA/g lipidless biomass) achieved. As omission of any single metal ions did not affect biomass concentration achieved, we concluded that metal ions components in production media may have affected lipid and GLA production by affecting pathways involved in the biosynthesis of lipid and GLA. This study reports the critical concentration of each metal ion for optimal lipid and GLA production by Cunninghamella sp. 2A1.