Growth and fatty acid composition of Nannochloropsis sp. grown mixotrophically in fed-batch culture

Abstract

The cell growth and eicosapentaenoic acid (EPA) yields of Nannochloropsis sp. were enhanced in the fed-batch cultures. With feeding glucose solution, the biomass reached 1.1 g dry wt l⁻¹ after 10 days' culture, which was 40% higher than that obtained in the batch culture (0.8 g dry wt l⁻¹). With supplement of nitrate solution, the biomass reached 1 g dry wt l⁻¹, and reached the stationary phase 2 days earlier than the others. The maximum of biomass (1.2 g dry wt l⁻¹) was obtained with the supplement of the mixture of glucose and nitrate solution. The EPA yields of Nannochloropsis sp. after 10 days' growth in the fed-batch cultures were 52 mg l⁻¹, 43 mg l⁻¹ and 56 mg l⁻¹ with, respectively, addition of nitrate, glucose and both together. In batch culture only 35 mg EPA l⁻¹ was obtained.