Raghuvanshi_2010_Protein.Pept.Lett_17_1412

In this work, we have compared the stability and activity of immobilized lipase and free enzyme of same specific activity. The immobilization was carried out on (3A x 1.5 mm) molecular sieve (a porous support) derivatized with glutaraldehyde as the functional group. Immobilization of the enzyme allowed the maintenance of 85% of the enzyme activity even after 8th cycle. In fact, only 12% of the enzyme activity was lost whereas the soluble enzyme lost 90% of its initial activity when incubated at 55 degrees C for 2 hrs. Additionally, the enzyme was stable between pH 7.5-9.0 unlike free enzyme. Kinetic parameters Km and Vmax for free and molecular sieve-immobilized lipase were found to be 0.3 mM and 1 micromole/min/ml, 3.7 mM and 8 micromole/min/ml, respectively. Moreover, the immobilized enzyme, on the porous support, cannot be denatured with detergents, and, therefore, it maintained the stability achieved by means of the multipoint covalent attachment on the molecular sieve support.