Evaluating the effect of medium composition and fermentation conditions on microbial oil production by a Fusarium strain isolated from the open ocean

As an important feedstock for biodiesel production, microbial oil has attracted considerable interest in recent years. Here, we investigated the effect of medium composition and culture conditions on cell growth and lipid accumulation of an oleaginous fungus Fusarium sp. 3A00501 on synthetic nitrogen-limited media. The optimal nitrogen source, carbon source, and C/N molar ratio in the medium for lipid accumulation were peptone, glucose, and 76, respectively. Additionally, the optimal initial pH of the medium and culture temperature for lipid production of the fungus were 6.0 and 30 degrees C, respectively. Under the optimized fermentation conditions, the cell biomass decreased, but the lipid content and yield increased (by about 45% and 27%, respectively) compared with the unoptimized conditions. The microbial oil produced by the fungus mainly contained palmitic, elaidic, oleic, linolenic, heneicosanoic, and eicosadienoic acids. The unsaturated fatty acids accounted for about 65% of the total fatty acids. This high percentage of unsaturated fatty acids in the oil was similar to the plant oils commonly used in biodiesel production. These results suggest that Fusarium sp. 3A00501 might be a promising strain to provide lipids for biodiesel production.