CO2 Sequestration by Chlorella vulgaris

Abstract

Rising carbon dioxide levels in the environment is a cause for serious concern. The rising levels of carbon dioxide can be dealt with in many ways. One of the ways is to reduce energy usage by optimizing process efficiency or by using renewable fuel sources. Another way is to capture the CO2 at the source of its emission. What sets apart, bio-sequestration from other carbon capture and storage (CCS) methods, is that it can help in reduction of CO2 using both of the strategies mentioned earlier. Micro-algal capture of CO2 using photo-bioreactors (PBR) allows greater photosynthetic efficiency over traditional plant growth. Both these factors combined, lead to better CO2 uptake or carbon dioxide assimilation. Optimal conditions of growth along with proper selection of culture(s) may allow additional benefits – bio-fuel production, protein production, etc. Chlorella strains have already been reported to have good CO2 sequestration capability as well as potential to produce biodiesel, which was why it was selected for our studies. All studies were carried out at 10% inlet CO2 in shake flasks containing 200 mL media with 10% inoculums by volume. Maximum specific growth rate and maximum carbon fixation rates were 0.596 mg L-1 day-1 and 586.5 mg L-1 day-1, respectively.