On-site concurrent carbon dioxide sequestration from flue gas and calcite formation in ossein effluent by a marine cyanobacterium Phormidium valderianum BDU 20041

Abstract In the recent past, there has been an upsurge in the use of microalgae to capture CO 2 . Microalgae are the most productive biological systems for generating biomass; they produce much more biomass than terrestrial organisms. In the present study, a cyanobacterium was exploited for combined CO 2 capture and ossein effluent treatment. Phormidium valderianum BDU 20041, a non-heterocystous filamentous marine cyanobacterium was grown in an open tank (∼550 L) in ossein effluent using flue gas (coal burnt) after cooling. After 10 days with unscrubbed flue gas, the organism’s biomass productivity, specific growth rate, CO 2 fixation rate, and lipid content were 30 mg L −1  d −1 , 0.10 μ d −1 , 56.4 mg C L −1  d −1 , and 12.74%, respectively. The predominance of C14 and C18 fatty acids in the total lipid content revealed its suitability as a potential biofuel. Results of this study show that flue gas from a coke oven can be used for mass cultivation of P. valderianum BDU 20041, which efficiently captures CO 2 and remediates ossein wastewater. Calcite formation by the organism in effluent was confirmed by scanning electron microscopy and energy dispersion spectroscopy studies. Biomass production employing flue gas coupled with the biomineralization of CO 2 in ossein effluent at a point source offers a novel self-sustaining strategy to mitigate CO 2 through outdoor cultivation and the subsequent generation of a biodiesel feedstock.