Kinetic study of a novel thermo-stable α-carbonic anhydrase for biomimetic CO2 capture

Biomimetic CO2 capture includes environmentally friendly solutions based on carbonic anhydrase (CA), an enzyme that increases CO2 absorption rate in conventional acid-gas scrubbing processes. The present contribution reports the characterization of a new recombinant carbonic anhydrase, SspCA, isolated from the thermophile bacterium Sulphurhydrogenibium yellowstonense sp. YO3AOP1. The kinetics of SspCA was characterized in terms of first order CO2 hydration rate according to a procedure based on CO2 absorption tests in a stirred cell apparatus. The first order kinetic constant at 25 °C was 9.16 × 106 L/(mol s). An appropriate investigation on SspCA stability was carried out to assess its long-term resistance to high temperatures as in all capture processes based on absorption/vacuum–desorption cycles. Its half-life was 53 and 8 days at 40 °C and 70 °C, respectively.