Immobilization of carbonic anhydrase on bentonite - chitosan composite and determination of its kinetic parameters and CO2 removal capacity

Greenhouse gas accumulation in the atmosphere resulting from industrialization and human activities is accepted as the main cause of climate change. Increasing temperatures by greenhouse gases have severe effects on meteorological and climatic events along with reduced available water resources. Carbon dioxide (CO2) is known as the most serious anthropogenic greenhouse gas in the atmosphere. In recent years the systems prepared by immobilizing carbonic anhydrase enzymes using CO2 as a substrate on some matrices are predominantly preferred. In this study, the bentonite-chitosan composite material was prepared as immobilization surface. The hCA I purified from human erythrocytes was immobilized onto the composite material by glutaraldehydemediated cross-linking technique. Immobilized hCA I retained 87.5 % of its initial activity 30 days of incubation at 4 degrees C. Besides, after 12 cycles of use the relative activity was 89.1 %. In addition, the CO2 removal capacity of immobilized hCA I was found as 7.41 +/- 0.95 mg CaCO3/mg hCA I with CaCO3 precipitation method. These results show that our novel composite hold a great potential as a CO2 removal tool.