An optimized approach towards bio-capture and carbon dioxide sequestration with microalgae Phormidium valderianum using response surface methodology

Abstract

As carbon dioxide emissions rise, there's need for alternative strategies, including microorganisms, to capture and mitigate them. The present study investigated on the capability and tolerance of microalgal strain, Phormidium valderianum to capture gaseous CO₂ at varying levels (5-30 %). A biomass productivity of 0.0216 ± 0.027 gL^-1day^-1 and rate of CO₂ fixation of 0.035 gL^-1day^-1 was obtained for 25 % CO₂ concentration. From this study, it is evident that higher CO₂ levels led to elevated carbohydrate concentration. In addition, protein concentration doubled with the introduction of 25 % CO₂. In optimization studies, pH 10, 25 % CO₂, and 200 mg/L of Ca(OH)₂ concentration was found to be optimal for biomass growth. A higher rate of CO₂ fixation of 0.315 gL^-1day^-1 was achieved at these optimum conditions using response surface methodology. Furthermore, the study demonstrated that microalgae, Phormidium valderianum has the potential to serve as a promising alternative for capturing CO₂ emissions.

Keywords: Biomass productivity; CO(2) fixation; Microalgae; Response surface methodology.