Enzyme immobilization. Part 4. Immobilization of alkaline phosphatase on Na-sepiolite and modified sepiolite

Alkaline phosphatase from calf intestinal mucous membrane was immobilized on the modified and unmodified Na-sepiolite. The effects of various factors such as concentration of enzyme solution, pH and temperature of immobilization medium, magnetic stirring and various thermodynamic parameters on the immobilization rate of alkaline phosphatase (APh) were evaluated. pH = 10 was optimal for enzyme activity for both the free enzyme and the sepiolite. Sepiolite with bilayer surfactant coverage (SBS) had high ability for immobilization of APh. APh immobilized on SBS showed approximately similar Vmax and Km in comparison with the free enzyme. By immobilization of APh on Na-sepiolite without surfactant (SWS) and sepiolite with monolayer surfactant coverage (SMS), Vmax decreased and Km increased.