Enzyme immobilization on ordered mesoporous materials: Effect of pH and enzyme size

The adsorption of lysozyme and horseradish peroxidase (HRP) on mesoporous molecular sieve, Al-MCM-41, and the effect of pH on it was investigated. Sodium phosphate buffer and sodium bicarbonate buffer were used for adjusting pH. The Al-MCM-41 was synthesized by the hydrothermal method using silicic acid, sodium hydroxide, cetyltrimethylammonium bromide (CTMABr) as template and distilled water as solvent. Al-MCM-41 was characterized by X-ray diffraction and nitrogen adsorption. Lysozyme molecules had greater loading amount than HRP, because lysozyme molecules match the pores of support but HRP molecules are bigger and just adsorbed on the outer surface. The optimum pH was 10 for lysozyme and 5.5 for HRP. These pHs are near isoelectric pH for both enzymes.

Keywords:

Enzyme immobilization , Horseradish peroxidase , Lysozyme , Al-MCM-41