Optimization of Process Parameters for the Production of γ-Linolenic Acid by Cunninghamella elegans CFR C07 in Submerged Fermentation

Abstract

The production of γ-linolenic acid (GLA) by the fungus Cunninghamella elegans CFR C07 in submerged fermentation was studied. Culture parameters such as carbon source and incubation time were optimized. Four different extraction methods using solvents with acid washed sand, glass beads, lyophilization and Soxhlet extraction were evaluated for improved extraction of lipids from the fungal biomass after fermentation. The GLA production was initially optimized in 250-mL flask and the process was demonstrated in a 3-litre fermentor. The maximum GLA production was 882 mg/L in shake flask culture and 733 mg/L in the fermentor. The study shows that Cunninghamella elegans CFR C07 is a potent organism for the production of GLA under submerged conditions.

Fig. 1

Cunninghamella elegans CFR C07 under optical microscope with oil immersion objective (at 40× magnification)

Fig. 2

Gas chromatogram showing the fatty acid methyl ester profile at different stages of incubation. The γ-linolenic acid (GLA) peak at retention time of 21.8 min on the 3rd, 4th and 5th day of incubation, respectively: a) not observed, meaning that there were no lipids, b) γ(GLA)=882 mg/L, and c) γ(GLA)=866 mg/L

Fig. 3

Comparison of isolated γ-linolenic acid (GLA) with standard GLA by thin layer chromatography: A=standard GLA, B=extraction method 3, C=extraction method 1 and D=extraction method 4