Biomitigation of CO2 and Extraction of Biomolecules Using <i>Leptolyngbya</i> sp.

Abstract

A cyanobacterial strain, Leptolyngbya sp., was used for CO2 biomitigation due to its effectiveness for bioconversion of CO2 and higher yield of biomass. In the present research study, CO2 biomitigation was done using cyanobacteria cultivated in scrubbed water containing sodium carbonate in equilibrium with various concentrations of CO2 (5%–30%), at different pH conditions (7–11), with different inoculum sizes (5%–12.5%) and at various temperatures (20°C–35°C). The biomass obtained after CO2 biomitigation was analyzed for its carbohydrate, protein, and lipid contents. The maximum biomitigation of CO2 was found to be in the range of 74.44±0.89% to 22.98±0.56% for CO2 concentration of 5% to 30%. The maximum productivities were found as follows: biomass, 27.71±0.12 mg/L/day; lipid, 6.62±0.06 mg/L/day; carbohydrate, 10±0.21 mg/L/day; and protein, 7.92±0.15 mg/L/day at pH 9, 15% CO2, inoculum size of 12.5%, and a temperature of 25°C. As the flue gas contains CO2 in the range of 10% to 15%, the present cyanobacterial strain could be viewed as a valuable aid for CO2 mitigation in the future.