Hanaa H. Abd El Baky, Gamal S. El-Baroty and Abderrahim Bouaid
In this work, the effect of various levels of CO2 (0.01, 0.03, 3.0, 9.0 and 12.0%) aeration on the biomass
production, lipid accumulation and its fatty acid profile as well as biodiesel properties of marine microalgae Dunaliella salina were investigated. The results show that the maximal biomass and lipid productivity (in parenthesis) in cultures aerated with different levels of 0.01, 0.03, 3.0, 9.0 and 12.0% CO2 were 255 (5.36), 412 (15.10), 781 (25.32), 1451 (41.96) and 951 mg/L (59.23 mg L-1d-1), respectively. Whereas, the lipid contents in cells were 2.33, 5.62, 10.28, 28.36 and 40.65%, respectively. Moreover, the levels of CO2 in culture medium had significant effect on fatty acid composition of D. salina. Linolenic and palmitic acids were identified as the major fatty acids in D. salina cells grown at different levels of CO2. The quality of biodiesel produced from algal lipid by a transesterification reaction was located between the limit imposed by the European Standards (EU 14214) and ASTM (US D6751). Based on the results obtained, D. salina could be used for mass-cultured in outdoor ponds, as a promising alternative to current CO2 mitigation strategy and as a suitable feedstock for biodiesel production.