Growth and Lipid Production of Two Microalgae Strains in Pilot Scale (35 L) Panel Photobioreactors

摘要

Microalgae are increasingly employed for production of various industrial chemicals. Lipids, which are a major microalgae product, are similar to plant based lipids and can be converted to biodiesel. Moreover, growing microalgae has many more advantages compared to plants in terms of lipid production. The objective of this study is to compare growth and lipid production performances of two different microalgae strains (Chlorella protothecoides and Chlorella variabilis) in pilot scale (35 L) panel photobioreactors. The study was carried out in indoor conditions under artificial illumination. Defined medium was used for growing microorganisms. After the runs, algae biomass was harvested by centrifugation and drying, lipid was obtained from the algae biomass by solvent extraction. The specific growth rate of C. protothecoides was 0.0022/h which corresponded to a doubling time of 313 days and yielded 11.1 g algal dry weight with 2.3% lipid content after 24 days run. C. variabilis performed better with a specific growth rate of 0.0030/h which corresponded to a doubling time of 234 days and yielded 16.2 g algal dry weight with 1.4% lipid content after 24 days run. The fatty acid compositions of the lipids were also determined, average molecular weight of the fatty acids were higher for C. Protothecoides lipids (870 g/mol compared to 837 g/mol).