Biocatalytic carbon dioxide capture promoted by carbonic anhydrase

Abstract

The rapid and steady increase in the concentration of CO2, the most abundant greenhouse gas in the atmosphere, leads to extreme weather and climate events. Due to the burning of fossil fuels (oil, coal and natural gas), the concentration of CO2 in the air has been increasing in recent decades by more than 2 ppm per year, and in the last year alone - by 3.29 ppm. To prevent the "worst" scenarios of climate change, immediate and significant reductions in CO2 emissions through carbon management are needed. Aim. Analysis of the current state of research and prospects for the use of carbonic anhydrase in environmental decarbonization programs. Results. Carbonic anhydrase (CA) is an enzyme that accelerates the exchange of CO2 and HCO3 in solution by a factor of 104 to 106. To date, 7 types of CAs have been identified in different organisms. CA is required to provide a rapid supply of CO2 and HCO3 for various metabolic pathways in the body, explaining its multiple independent origins during evolution. Enzymes isolated from bacteria and mammalian tissues have been tested in CO2 sequestration projects using carbonic anhydrase (CA). The most studied is one of the isoforms of human KAz - hCAII - the most active natural enzyme. Its drawbacks have been instability over time, high sensitivity to temperature, low tolerance to contaminants such as sulphur compounds and the impossibility of reuse. Molecular modelling and enzyme immobilisation methods were used to overcome these limitations. Immobilisation was shown to provide greater thermal and storage stability and increased reusability. Conclusions. Capturing carbon dioxide using carbonic anhydrase (CA) is one of the most cost-effective methods to mitigate global warming, the development of which requires significant efforts to improve the stability and thermal stability of CAs.

Keywords

• climate
• decarbonization
• biosequestration of co2
• carbonic anhydrase
• immobilization of enzymes.