Characterization and Properties of a New Thermoactive and Thermostable Carbonic Anhydrase

A new carbonic anhydrase was isolated and characterized from the thermophilic bacterium Sulfurihydrogenibium sp. YO3AOP1. The encoding gene was cloned and expressed in Escherichia coli and the recombinant protein purified to homogeneity. This enzyme (SspCA) belongs to the ? class of the carbonic anhydrase family, is a monomer of 26.1 kDa and shows esterase activity. The kinetic parameters were determined by using CO 2 and p-nitrophenylacetate (p-NpA) as substrates. Thermoactivity and thermostability studies showed that SspCA is active in the temperature range from 0 to 100 °C and retains full activity after 2 h incubation at 100°C. SspCA was immobilized within a polyurethane foam and was found to be unalterably active and stable up to 50 h at 100 °C.