Effect of CO2 concentration on growth and photosynthesis of Spirulina platensis

Abstract

The effect of different CO2 concentrations on the growth and photosynthesis of Spirulina platensis NIES 46 was examined in terms of cell growth and photosynthetic parameters. Under 0.01% CO2, growth stopped after the depletion of the dissolved inorganic carbon and the cell yield was low. The cells grown under 0.07% CO2 exhibited no change in their growth rate when compared with the 0.03% CO2-grown culture, yet the cell yield increased from 1.2 to 3.6 g/l. The cells under 1% CO2 showed the lowest growth, even though the inorganic carbon remained at 50-60 mg/l and pH 7.5-8.0. The photosynthetic rates under 0.03 and 0.07% CO2 were higher than those under 0.01 or 1%. Accordingly, among the tested C02 concentrations, 0.07% C02 was found to be the best for a high-density culture of S. platensis NIES 46.