Conversion of NaHCO to Na CO with a growth of Arthrospira platensis cells in 660 m raceway ponds with a CO bicarbonation absorber.

The weight ratio of Na CO /NaHCO was investigated in order to improve microalgal productivity in large-scale industrial operations by converting NaHCO to Na CO with a growth of Arthrospira platensis cells in 660 m raceway ponds. Two microalgal cultivation systems with a NaHCO by-product (SPBP) and a CO bicarbonation absorber (CBAP) were firstly thoroughly introduced. There was a 13.3% decrease in the initial weight ratio of Na CO /NaHCO resulting in a 25.3% increase in the biomass growth rate with CBAP, compared to that of SPBP. Increased sunlight intensity, solution temperature and pH all resulted in both a higher absorbance and release, thereby increasing the weight ratio of Na CO /NaHCO during the growth of A. platensis. The biomass growth rate was peaked at 39.9 g m  day when the weight ratio of Na CO /NaHCO was 3.7. Correspondingly, the cell pigments (chlorophyll a and carotenoid) and trichome size (helix pitch and trichome length) reached to a maximum state of 8.47 mg l , 762 μg l , 57 and 613 μm under the CBAP system.