Assessment of the Potential of CO2 Sequestration from Cement Flue Gas Using Locally Isolated Microalgae

Carbon dioxide (CO2) emissions are rapidly escalating due to industrialization and urbanization worldwide, resulting in many long-term adverse effects such as global warming. Industrial flue gases which contain 3-30% CO2 (v/v) are a major constituent of global CO2 emissions. Employing microalgae for biological fixation of CO2 from flue gas is a prospective strategy for the reduction of CO2 emissions since microalgae have the capability of utilizing inorganic carbon to rapidly generate biomass via photosynthesis. In the current study, the locally isolated microalgal strains Chlorella sp. and Desmodesmus sp. were employed to assess the CO2 sequestration potential from simulated flue gas, comparable to the emissions from the cement industry. The gross calorific values (GCVs) were determined to evaluate the potential of employing microalgal biomass for co-firing processes. Desmodesmus sp. showed the highest CO2 tolerance, as it exhibited a biomass productivity and CO2 fixation rate of 1.17 g L-1 and 0.26 g L-1 day(-1) respectively under undiluted flue gas (15.50% CO2). However, the GCVs of Chlorella sp. biomass were higher than Desmodesmus sp. biomass under all flue gas dilutions. Nonetheless, the GCVs of Desmodesmus sp. were in the range of 23.277-24.202 MJ/kg, comparable to biomass typically used in co-firing applications.