Harnessing the potential of microalgae in sequestration of CO2 emissions: Removal mechanisms, optimization strategies, and bioenergy production
Adegoke Isiaka Adetunji, S’fiso Thuthukani Gumbi, Mariana Erasmus
Abstract
The rise in anthropogenic activities increases the release of greenhouse gases, causing serious hazards to immediate environments and public health. Among the greenhouse gases, carbon dioxide contributes significantly towards massive emissions that eventually lead to global warming. As a result, decarbonization of carbon from polluted spaces (e.g., the atmosphere) is imperative. Microalgae serve as a promising, economical, sustainable, efficient, and eco-friendly bio-factory for the sequestration and conversion of CO 2 into biomass in the presence of sunlight. The microalgal CO 2 fixation efficiency depends on temperature, pH, CO 2 concentration, light intensity, and culture medium. Strategies such as random mutagenesis, targeted genetic modifications, and the use of nanoparticles, phytohormones, and artificial intelligence are employed to enhance CO 2 capture by microalgae. Microalgal biomass is a vital feedstock for the production of beneficial bioenergy, including biodiesel, biogas, bioethanol, and biohydrogen. Thus, this review focuses on the mitigation of CO 2 emissions using microalgae. In addition, it elucidates bioprocess parameters that influence CO 2 fixation as well as the technologies that can be applied for improved CO 2 capture by microalgae coupled with biofuels that are formed from microalgal biomass. Techno-economic analysis of carbon sequestration by microalgae is also discussed.