Coimmobilization Of α-amylase And Glucoamylase Onto Carbon Nanotubes

Glucoamylase and α-amylase are two important enzymes in producingglucose in industry. They have synergistic action on hydrolysis of starchproducing glucose. In this article, they are coimmobilized onto oxided mutiwalled carbon nanotubes by covalent attachment.In this paper, carbon nanotubes have been purified using nitric acidoxidation, and oxided by mixed acid method, producing carboxyl on carbonnanotubes. Glucoamylase andα-amylase were covalently attached ontocarbon nanotubes using EDC and NHS. The optimum condition forcoimmobilization are that mass ratio of α-amylase and glucoamylase is1.5:1,the pH is5.0and the temperature is20℃. The amount of covalentlybound a-amylase and glucoamylase was found0.3mg/mg support. Theoptimum temperature, and pH of coimmobilized enzymes were investigated.The relative activity of coimmobilized α-amylase and glucoamylase is60%.The coimmobilized α-amylase and glucoamylase exhibited betterthermostability than the free ones. The coimmobilized α-amylase and glucoamylase were characterized using FT-IR, TEM, UV-Vis, Raman, XPS,CD spectroscopy.