Ablayeva A.
2nd year doctoral student in the specialty “Environmental Protection Technology” ENU named after. Gumileva, Astana

Abstract
CO₂ forms the largest component in coal combustion flue gas (Xing Zhang, 2015). Carbon dioxide (CO₂) fixation is an important process in mitigating the harmful effects of climate change caused by greenhouse gas emissions. One promising method of CO₂ fixation is through the use of microalgae. These tiny organisms are capable of photosynthesis, converting light energy into chemical energy and fixing atmospheric CO₂ into organic compounds. Microalgae are known for their fast growth rates and high CO₂ assimilation rates, making them an attractive option for CO₂ mitigation. In fact, some species of microalgae can fix up to 10 times more CO₂ than land-based plants. Furthermore, microalgae can grow in a wide range of environments, including wastewater, saline water, and brackish water, making them versatile and sustainable. In addition to CO₂ fixation, Chlorella microalgae also remove other pollutants from flue gases, such as sulfur dioxide (SO₂) and nitrogen oxides (NOx). These pollutants can be toxic and contribute to acid rain and smog. Chlorella microalgae are able to remove these pollutants through a process known as bioadsorption, where the pollutants are adsorbed onto the surface of the microalgae. This review presents an outlook on microalgal propagation systems for CO₂ sequestration.

Keywords: Microalgae, CO₂ fixation, flue gas, utilization, photobioreactor.