Sequestration of carbon dioxide and production of biomolecules using cyanobacteria

A cyanobacterial strain, Synechococcus sp. NIT18, has been applied to sequester CO₂ using sodium carbonate as inorganic carbon source due to its efficiency of CO₂ bioconversion and high biomass production. The biomass obtained is used for the extraction of biomolecules - protein, carbohydrate and lipid. The main objective of the study is to maximize the biomass and biomolecules production with CO₂ sequestration using cyanobacterial strain cultivated under different concentrations of CO₂ (5-20%), pH (7-11) and inoculum size (5-12.5%) within a statistical framework. Maximum sequestration of CO₂ and maximum productivities of protein, carbohydrate and lipid are 71.02%, 4.9 mg/L/day, 6.7 mg/L/day and 1.6 mg/L/day respectively, at initial CO₂ concentration: 10%, pH: 9 and inoculum size: 12.5%. Since flue gas contains 10-15% CO₂ and the present strain is able to sequester CO₂ in this range, the strain could be considered as a useful tool for CO₂ mitigation for greener world.