Large-Scale Cultivation of Spirulina for Biological CO(2) Mitigation in Open Raceway Ponds Using Purified CO(2) From a Coal Chemical Flue Gas

In order to select excellent strains with high CO(2) fixation capability on a large scale, nine Spirulina species were cultivated in columnar photobioreactors with the addition of 10% CO(2). The two species selected (208 and 220) were optimized for pH value, total dissolved inorganic carbon (DIC), and phosphorus content with intermittent CO(2) addition in 4 m(2) indoor raceway ponds. On the basis of biomass accumulation and CO(2) fixation rate in the present study, the optimum pH, DIC, and phosphate concentration were 9.5, 0.1 mol L(−1), and 200 mg L(−1) for both strains, respectively. Lastly, the two strains selected were semi-continuously cultivated successfully for CO(2) mitigation in 605 m(2) raceway ponds aerated with food-grade CO(2) purified from a coal chemical flue gas on a large scale. The daily average biomass dry weight of the two stains reached up to 18.7 and 13.2 g m(−2) d(−1), respectively, suggesting the two Spirulina strains can be utilized for mass production.