Comparative Carbon Dioxide Capture from Air between Chlorella vulgaris and Chlorella sorokiniana

Background/Objectives: In this research, the potential of a commercial microalgae species namely, Chlorella vulgaris and a native microalgae species isolated from a palm oil mill effluent, Chlorella sorokiniana to capture carbon dioxide from the air was investigated. Methods/Statistical Analysis: Both of the species were cultured in Bold Basal Medium (BBM) at three different concentrations denoted as 1.0 BBM, 2.0 BBM and 3.0 BBM. Among the parameters that were analyzed included pH value, optical density, specific growth rate, dry biomass and the rate of carbon dioxide gas captured by the microalgae. Findings: Different medium concentrations caused a different growth rate of C. vulgaris and C. sorokiniana. C. vulgaris favored an environment with a lower pH value ranging from pH 6.0-6.5 while the native isolated microalgae species, C. sorokiniana prefers a higher pH medium which has a range of 7.0-8.0. In addition, C. sorokiniana has a higher specific growth rate, 0.0452 h^-1 in 3.0 BBM compared to C. vulgaris that only has a specific growth rate of 0.0013 h^-1 in 1.0 BBM. C. vulgaris had the highest dry biomass value of 0.016 g/L in 1.0 BBM in comparison to C. sorokiniana with 2.438 g/L for the dry biomass in 3.0 BBM. It is also observed that the C. sorokiniana microalgae in 3.0 BBM has the highest potential of capturing carbon dioxide gas from air at a rate of 4.584 g/L in comparison with C. vulgaris microalgae in 2.0 BBM that only captured 0.030 g/L of carbon dioxide from air. Application/Improvements: The locally isolated microalgae have shown a vast potential as an alternative for carbon dioxide capture.