Studies of CO2 Sequestration by Chlorella Vulgaris in Stirred Tank Batch Type Photobioreactor

Abstract

Global warming is becoming a grim intimidation to the nature. The earth’s temperature is increasing every year which may result in weather extremities, rise in sea levels, annihilation of species, glaciers retreat, and similar other calamities. The rise in global temperature is attributed primarily to the high and persistently increasing amount of carbon dioxide (CO2) gases in the atmosphere. The techniques to lower the effects of CO2 are classified as chemical reaction based strategy (abiotic) and biological mitigation method (biotic). Abiotic method captures CO2 by reaction with chemical compounds before it is released into the atmosphere. But, the disadvantages of this method are that the chemical reactions are highly energy intensive and costly; and the problematic disposal of the wasted chemical compounds. On the other hand, biological mitigation is more favorable as it directly converts CO2 into biomass. Microalgae are able to capture solar energy and CO2 with an efficiency of 5-10 times greater than that of higher plants. This technique can help mitigate global warming and produce a large number of value-added products like pigments, carotenoids, proteins, carbohydrates, lipids, biodiesel etc. This dissertation describes the effectiveness of Chlorella vulgaris, used in a photobioreactor at different concentrations (0.04%, 5%, 10%, 15% and 20%) of CO2 in Fogg’s media with 10% (of total volume) inoculum. 10% is the CO2 concentration at which most of the kinetic parameters as well as total CO2 fixed and fixation rate is found to be maximum. The pH and CO2 concentration for this culture were also optimized