Magnetic halloysite-functionalized carbonic anhydrase nanobiocatalyst for superior stability and sustainable CO2 sequestration.

Biological CO2 sequestration and storage as inert solid carbonates is a promising approach utilizing carbonic anhydrase. In present study, we report the synthesis of a magnetic carbonic anhydrase nanobiocatalyst using halloysite nanotubes (HNTs) as the backbone. Magnetic HNTs were functionalized with polydopamine (PDA) and polyethylenimine (PEI), followed by covalent enzyme immobilization via glutaraldehyde crosslinking. The nanobiocatalyst achieved 58.37 % enzyme loading with 63.58 % retained activity. Comprehensive characterization confirmed the effective anchoring of enzyme molecules on the surface of the functionalized magnetic HNTs. The nanobiocatalyst demonstrated superior stability across varying pH and temperature conditions compared to free carbonic anhydrase. It retained 65.2 % activity even after 10 weeks of storage and remained functional for 17 reuse cycles, indicating excellent operational stability. Additionally, the nanobiocatalyst exhibited enhanced catalytic efficiency and biomimetic CO2 sequestration with reusability potential. This approach offers a significant improvement over conventional enzyme immobilization techniques by providing enhanced stability, reusability, and catalytic performance. The use of magnetic HNTs as a support allows for easy recovery and reuse, making this nanobiocatalyst highly suitable for industrial applications in carbon capture and storage. With its superior stability and performance, this system presents a promising strategy for future advancements in sustainable carbon management and green technology.