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.