A novel method for the immobilization of urease on phosphonate grafted iron oxide nanoparticle Banalata Sahoo and Prof. P. Pramanik Department of Chemistry, Indian Institute of Technology Kharagpur, India ABSTRACT
IMPORTANCE
The development of simple and reliable technique for the immobilization of enzymes is an important part of biotechnology. We demonstrate herein the modification of magnetic nanoparticles and its use in the immobilization of the urease enzyme. Magnetite particles were prepared by simple co-precipitation method in aqueous medium and then subsequently coated with phosphonomethyl iminodiacetic acid. Urease was immobilized on the magnetic nanoparticles through a carbodiimide reaction.
Nanosized carboxylic acid functionalized magnetic particles with high magnetic responsivity and excellent dispersibility have been prepared through a facile one-pot synthesis and was successfully applied, for enzyme immobilization. The immobilized urease exhibited excellent catalytic activity over six times successive reuse as well as the stability. By using immobilization technique on this magnetic nanoparticle it is easy to isolate product from reaction mixture enabling to control the reaction and simultaneously lowers the cost of enzyme.
RESULTS & DISCUSSIONS .
The immobilized enzyme has activity not affected by wide change of pH, longer period of storage without losing catalytic activity and high thermal stability. The immobilized enzyme shows up to 70% of relative activity after five times reuse.
Schematic procedure for the immobilization of urease on the PMIDA functionalized iron oxide nanoparticle
Free urease
Immobilized urease
Km = 1.1 10-1 mol/l TEM micrographs and DLS size distributions of Fe3O4– PMIDA nanoparticles before (a) and after (b) conjugation with urease
Vmax =1.0
Km = 2.0
10-3 mol.l-1/s
on enzymatic activity
Banalata Sahoo, et al., Journal of Molecular Catalysis B: Enzymatic 69 (2011) 95–102
10-1 mol/l
Vmax 2.0 10-4 mol.l-1/s
Effect of Temp.
REFERENCE
Reusability of the immobilized urease
pH