Synthesis of Efficient Carbonic Anhydrase-Fe-MOF Composite for Enhancing CO₂ Capture

The increasing concentration of atmospheric carbon dioxide (CO₂), primarily from fossil fuel combustion, poses a significant environmental threat and necessitates effective capture technologies. Carbonic anhydrase (CA), a zinc-containing metalloenzyme, has garnered attention for its exceptional catalytic efficiency in accelerating CO₂ hydration. However, its industrial application is limited by thermal instability, short operational lifespan, and poor reusability. This study investigates the immobilization of CA onto the biocompatible metal-organic framework, NH₂-MIL-101(Fe) to enhance enzyme stability and reusability for CO₂ capture applications. The MOF was synthesized and characterized by XRD, FTIR, BET, SEM, TEM, TGA, and EDX. Enzyme loading and immobilization efficiency were quantified, yielding a loading of 0.0394 mg CA/mg MOF and an immobilization efficiency of 60%. Activity assays demonstrated an 80% retention of catalytic function post-immobilization. Thermal stability tests showed significantly improved enzyme resilience at elevated temperatures, and the composite retained 40% of its activity after six reuse cycles. In CO₂ capture experiments, the CA/MOF composite achieved a CaCO₃ yield comparable to that of free CA, with the added benefit of enhanced operational stability. This study confirms that NH₂-MIL-101(Fe) is a promising support for CA immobilization, enabling efficient and reusable biocatalytic CO₂ capture systems with potential for scalable environmental applications.