Carbonic anhydrase catalyzed bio-sequestration of CO2 to form HCO3-, followed by trapping as solid CaCO3 is one of the most promising technologies for CO2 capturing. The effects of reaction condition on the CO2 hydration using free carbonic anhydrase were systematically investigated. In order to improve the stability of the enzyme and facility its recycling, the carbonic anhydrase was in situ encapsulated inside hollow fibers via a novel co-axial electrospinning technology. Compared with the free enzyme, the immobilized carbonic anhydrase showed much improved thermal stability and suffered much reduced inhibitory effects from cation ions, such as Cu2+ and Fe3+. After 11 reuses, the immobilized enzyme retained about 81.9% of its original activity by comparing the amount of formed CaCO3 precipitation. In the presence of immobilized carbonic anhydrase, both calcite and vaterite CaCO3 solid were formed; while in the absence of enzyme or with free carbonic anhydrase, only calcite CaCO3 was observed.