Immobilization of Carbonic Anhydrase on Chitosan Stabilized Iron Nanoparticles for the Carbonation Reaction
2012
Yadav, Renu | Joshi, Meenal | Wanjari, Snehal | Prabhu, Chandan | Kotwal, Swati | Satyanarayanan, T. | Rayalu, Sadhana
Carbonic anhydrase (CA) has been immobilized on chitosan stabilized iron nanoparticles (CSIN) for the biomimetic carbonation reaction. CSIN was characterized using scanning electron microscope, energy dispersive X-ray, X-ray diffraction spectroscopy, and Fourier transform infrared analysis. The effect of various parameters such as pH, temperature and storage stability, on immobilized CA was investigated using a p-NPA assay. Kinetic parameters of immobilized and free CA (K ₘ and V ₘₐₓ values) were also evaluated. The K ₘ and V ₘₐₓ for immobilized CA was 1.727 mM and 1.189 μmol min⁻¹ ml⁻¹, respectively, whereas for free enzyme the K ₘ and V ₘₐₓ was 1.594 mM and 1.307 μmol min⁻¹ ml⁻¹, respectively. It was observed that the immobilized enzyme had longer storage stability and retained 50 % of its initial activity upto 30 days at room temperature. CA immobilized on CSIN has been used for hydration of CO₂, and the results were validated by using a gas chromatographic method. Proof of concept has been established for the biomimetic carbonation reaction. Immobilized CA show reasonably good CO₂ sequestration capacity of 21.55 mg of CaCO₃/mg of CA as compared to CO₂ sequestration capacity of 34.92 mg of CaCO₃/mg of CA for free CA respectively, under a limiting concentration of CO₂ (14.5 mg of CO₂/10 ml).
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