EFFECT ON LIPID ACCUMULATION OF MARINE OLEAGINOUS MICROALGAE UNDER CO2 ENRICHMENT CULTIVATION

Three marine oleaginous microalgae Isochrysis galbana CCMM5001, Isochrysis sp. CCMM5002 and Nannochloropsis sp. CCMM7001 were cultured under different CO2 concentrations of ambient air (0.03%), 5% and 10% respectively. The growth characterization, total and neutral lipid accumulation of these microalgae were investigated. The results showed that CO2 enrichment cultivation could increase the growth of all three microalgae, but the optimum CO2 concentrations were different. The maximum biomass yield of Isochrysis galbanaCCMM5001 and Isochrysis sp. CCMM5002 were (182.287.07) mg/(Ld) and (164.227.10) mg/(Ld) when culturing with 10% CO2. However, the maximum biomass yield of Nannochloropsis sp. CCMM7001 was (122.251.17) mg/(Ld) when culturing with 5% CO2. As the CO2 concentration increasing, the total lipid and neutral lipid of these microalgae increased significantly. When culturing with 10% CO2, total lipid content of Isochrysis galbana CCMM5001, Isochrysis sp. CCMM5002 and Nannochloropsis sp. CCMM7001 were (45.154.03) %, (47.151.20) % and (41.201.69) % respectively. The maximum neutral lipid content of all three microalgae could be accumulated in stationary phase. The fatty acid analysis of the microalgae showed the relative content of C14-C18 fatty acid which suitable for biodiesel preparation maintained at 90% when culturing with different CO2 concentrations. The results indicate the marine oleaginous microalgae in this study have high carbon dioxide fixation ability They are the potential excellent strains and could be used in marine bio-energy development coupled with CO2 emission reduction.