ABSTRACT
This work investigated the cultivation of Arthrospira (Spirulina) platensis BP in a photobioreactor under light intensities of 635, 980, 1300, and 2300 µmol m-2 s-1, using a semi-continuous mode to keep cell concentration at optical densities (OD) of 0.4, 0.6, and 0.8. The highest productivity of biomass (0.62 g L-1 d-1) and phycocyanin (123 mg L-1 d-1) were obtained when cells were grown under a light intensity of 2300 µmol m-2 s-1 at OD 0.6. At this concentration, the efficiency of energy consumption to the biomass of algae was around 2.26-2.31 g (kW h)-1 d-1, while, a maximum photosynthetic efficiency of 8.02% was obtained under a light intensity of 635 µmol m-2 s-1 at OD 0.8. This indicates how light intensity, cell concentration, and light-dark conditions can enhance biomass and phycocyanin production, if well manipulated.
