In the present study Chlorela sp. and Scenedesmus sp. were cultivated in BG11 medium
under different CO2 concentrations. The effects of different CO2 concentrations on the growth of both microalgae are shown in Figs 2 - 3. In a subsequent study period (5-19 days) the algae biomass growth increased proportionally to the increase in CO2 concentration. The slight growth and its proportional increase depending on the CO2 concentration were characteristic of the latest algae biomass growth period (Fig.2, curves 2-5). A similar effect of CO2 concentrations on Scenedesmus sp. growth was also determined (Fig. 3). The highest concentrations of
biomass were detected in the medium under CO2 concentration of 24% and reached the maximum
biomass of 0.2 g l-1 and 0.12 g l-1 in Chlorella sp. and Scenedesmus sp., respectively.