Biomass Production of Green Microalgae Chlorella vulgaris through CO2 Sequestration

Abstract

The highly abundant carbon dioxide (CO2) in the atmosphere would cause the greenhouse effect, which leads to global warming. Because of that, many researchers conduct experiments to reduce CO2 gas release into the atmosphere. Microalgae are photosynthetic microorganisms that have been used to capture CO2 gas and convert it into biomass. However, the CO2 gas addition into media might lower the pH and shift the optimum cell growth condition, which requires a suitable medium for CO2 gas as a carbon source. Chlorella vulgaris was used in this study for the CO2 gas sequestration concerning biomass production. Several media, pH, and NaOH concentrations were screened to find the optimum condition for biomass production with CO2 gas. From the experiments, macro- and micronutrients of the Tris-Acetate-Phosphate (TAP) medium were effective for cell growth. At the same time, Tris and acetic acid can be substituted by Na2CO3, NaHCO3, and CO2 gas. The optimum pH condition for biomass production was 7. Meanwhile, 60 mM NaOH solution was the optimum condition for converting the CO2 gas into biomass. This study found that CO2 gas can be sequestrated into microalgal biomass, even though Tris as the initial carbon source still produces higher biomass.