Chitosan/Siloxane Hybrid Polymer: Synthesis, Characterization and Performance as a Support for Immobilizing Enzyme

A hybrid polymer derived from siloxane and chitosan was obtained by sol-gel technique using tetraethoxysilane (TEOS) as a precursor. The hybrid support was chemically modified with epichlorohydrin and used to immobilize lipase from Burkholderia cepacia. The hybrid SiO(2)-chitosan formed new macromolecular structure in which the inorganic particles are dispersed at the nanometer scale in the organic host matrix and bounding through covalent bonds. A comparative study between free and immobilized lipase was provided in terms of pH, temperature, kinetic parameters and thermal stability. The pH for maximum hydrolysis activity shifted from 7.0 for the soluble lipase to 6.1 and the optimum temperature remained at 50 degrees C after immobilization. The patterns of heat stability indicated that the immobilization process provided the stabilization of the enzyme and the epoxy SiO(2)-chitosan derivative was almost 30-fold more stable than soluble lipase at 60 degrees C.