Carbon dioxide capture and bioenergy production using biological system – A review

With the growing use of fossil fuels and industrial activity, the amount of carbon dioxide (CO₂) emission is continuously increasing and is considered a primary contributor to climate change. CO₂ emissions from stationary resources (coal fire, cement plants, and other industry) can be reduced by using various carbon capture and sequestration (CCS) technologies. In this article, recent advancements in various biological methods (i.e., carbonic anhydrase (CA), hydrogenation of CO₂ to formate, reduction of CO₂ to methane, CO₂ conversion into methanol by enzyme cascade, and the role of RuBisCo enzyme) that have been reported for CO₂ capture are discussed, along with their advantages and limitations. A brief overview of other physicochemical (absorption, adsorption, cryogenic, and membrane) technologies is also provided. Although biological methods are ecofriendly and can be performed under ambient conditions, these approaches are still not cost effective, as the reactions require cofactors, and the enzymes lose activity when exposed to hot flue gas and ionic liquids. Most captured CO₂ is stored by mineralization using a geological and ocean storage method without providing any economic benefit. It is a question of interest as to how we can utilize CO₂ and generate revenue. Utilization of CO₂ as a feedstock to produce bioenergy is a possible approach. Various microbes capable of utilizing CO₂ as feedstock and producing biofuels (biodiesel and bioalcohol) have been reported. These two technologies, i.e., CO₂ capture and bioconversion of CO₂ into bioenergy, can be integrated to develop a process that not only mitigates CO₂ effects on the environment but also solves energy problems while generating revenue.