Immobilization and characterization of bovine carbonic anhydrase enzyme on iron oxide magnetic nanoparticles: investigation of potential applicability in CO2 removal

Abstract

In this study, carbonic anhydrase (CA) was purified from bovine erythrocytes using a Sepharose 4B-l-tyrosine sulfanilamide affinity chromatography method, achieving an 83.42-fold purification. The source of the enzyme is bovine blood erythrocytes, which were obtained from a slaughterhouse. Following purification, two different support materials (Fe₃O₄–NH₂ and Fe₃O₄@SiO₂–NH₂) were synthesized for enzyme immobilization, and sığır karbonik anhidraz (BCA) was immobilized via the covalent binding method. The support material prior to immobilisation and the enzyme-bound support material after immobilisation were characterised by FT-IR, SEM-EDX and VSM. The kinetic parameters of free BCA were determined as Km = 4.888 mM and Vmax = 3.081 µmol min⁻¹ mL⁻¹. For the immobilised enzyme, Km and Vmax values were 16.160 mM and 2.195 µmol min⁻¹ mL⁻¹ on support material I, and 9.369 mM and 1.810 µmol min⁻¹ mL⁻¹ on support material II, respectively. The operational stability of the immobilised enzymes was evaluated through 20 consecutive reuse cycles, during which support material I retained 86% of its initial activity, while support material II retained 73%. In contrast, the free enzyme could only be used once due to its loss of activity. Storage stability tests were performed by incubating the samples at 4 °C for 60 days. At the end of the incubation period, support material II maintained 60% of its initial activity, and support material I retained 49%, whereas the free enzyme preserved only 17% of its activity under identical conditions. Finally, the potential applicability of the immobilised BCA for CO₂ removal was investigated, demonstrating its promise as a stable and reusable biocatalyst for CO₂ capture applications.

Graphical Abstract