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 CO2. 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 CO2 capture and ossein effluent treatment. Phormidium valderianum BDU 20041, a non-heterocystous filamentous marine cyanobacterium was grown in an open tank (∼550L) in ossein effluent using flue gas (coal burnt) after cooling. After 10days with unscrubbed flue gas, the organism’s biomass productivity, specific growth rate, CO2 fixation rate, and lipid content were 30mgL−1d−1, 0.10μd−1, 56.4mgCL−1d−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 CO2 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 CO2 in ossein effluent at a point source offers a novel self-sustaining strategy to mitigate CO2 through outdoor cultivation and the subsequent generation of a biodiesel feedstock.