Development of integrated system for biomimetic CO2 sequestration using the enzyme carbonic anhydrase

The enzyme, carbonic anhydrase, is the biological catalyst responsible for the interconversion of CO2 and bicarbonate in living organisms. The present research is aimed at the development of a CO2 scrubber that can be used to reduce CO2 emissions from, for example, fossil-fuel-burning power plants. In this system, the enzyme works as a catalyst to accelerate the rate of CO 2 hydration for subsequent fixation into stable mineral carbonates, the cou nterions for which may be supplied from such sources as brines from saline aquifers, waste brines from desalination operations, or seawater. Proof of principle has already been demonstrated. One of the requirements for the en zyme will be that it must be able to function in the presence of other chem ical species likely to be present in the industrial application. The presen t results show excellent enzyme activity in the presence of low levels of S Ox and NOx (that might be expected from flue gases) and also in solution re presentative of seawater. The effects of SOx and NOx are of interest becaus e, although emissions of these species are strictly controlled, some very l ow level will still be present. The reason for examining enzyme performance in seawater-like solutions is to give a better approximation of the compos itions likely in actual process streams based on either seawater or other b rines.