Synthesis of magnetic Fe-N doped porous carbon possessing hollow-acicular structure with high activity and stability for lumbrukinase adsorptive immobilization

A magnetic Fe-N doped hollow acicular porous carbon (FeN-HAPC) with dopamine was successfully fabricated using a green free template-removal strategy for Lumbrukinase (LK) immobilization. FeN-HAPC was characterized by SEM, TEM, XRD, N-2 adsorption, XPS and FT-IR. Results revealed that immobilized LK through adsorption on FeN-HAPC possessed high activity (350 U/mg), good reusability (similar to 80% of initial value after 7th usage), and storage stability (86.0% at 4 degrees C for 30 days). Moreover, dopamine modification of FeN-HAPC (FeNHAPC@DA) further significantly enhanced the amount and adsorption affinity towards immobilized LK, and thus exhibiting higher enzyme activity (617.5 U/mg) and reusable performance (87.3% for the 7th usage), and storage stability (92.4% at 4 degrees C for 30 days). Its deactivation half-life was 6-14 times longer than those immobilized over conventional Fe3O4 microsphere or free ones. The deactivation energy of FeN-HAPC@DA/STI-LK was 146 kJ/mol, much higher than free LK and Fe3O4@CTS/STI-LK samples. Thus, the composite prepared in this study, attributed to possessing hollow structures with magnetic characteristic, high specific surface area, and high dispersion of affinity sites can be deemed as a promising candidate for enzyme adsorptive immobilization in practical applications.