ABSTRACT
The ubiquitous carbonic anhydrase superfamily (CAs, EC 4.2.1.1) constitutes a cluster of metalloenzymes catalysing the carbon dioxide hydration/dehydration reaction (CO2 + H2O ⇄ 1 +H+), which is physiologically significant. The ions H+ and 2, as well as CO2, are the metabolites dispersed through the liquids of all living organisms and engaged in a wide range of physiological processes, including biosynthesis, photosynthesis, respiration, pH homeostasis, and electrolyte secretion. An increase in the atmospheric CO2 level caused by the anthropogenic activities and the impacts of this greenhouse gas have encouraged the scientific community to concentrate their studies on different alternatives to reduce CO2 emissions. Our groups have chosen the extreme CAs to capture CO2 from the engine fume of a combustion cycle to meet this task. The use of SspCA, a CA identified in the bacterium Sulfurihydrogenibium yellowstonense living at temperatures up to 110°C, is outlined in this chapter. SspCA catalyses the CO2 hydration reaction with a very high k cat (9.35 × 105). Moreover, it is a robust ‘extreme biocatalyst’ since the excellent catalytic activity persists even if the enzyme is heated at high temperatures for an extended period. Through the biomimetic strategy, carbon capture was pursued to immobilize the thermostable SspCA onto the polyurethane foam, magnetic particles, supported ionic liquid membranes, and vital support (bacterial cellular surface). As a result, the biochemical features of extreme CAs found in thermophilic microorganisms can play a crucial part in combating the rise in CO2 in the atmosphere induced by anthropogenic activity.
