Enhanced activity and stability of α-amylase immobilized on alumina

alpha-amylase was immobilized on alumina via adsorption. The support and the immobilized enzymes were characterized using XRD, IR spectra and N-2 adsorption studies. The efficiency of immobilized enzymes for starch hydrolysis was tested in a batch reactor. The effect of two different calcination temperatures on properties of the support as well as on immobilization was studied. From XRD, IR and N-2 adsorption studies it was confirmed that the enzyme was getting adsorbed only on the external surface of the support. pH, buffer concentration and substrate concentration had a significant influence on the activity of immobilized enzyme. K-m for immobilized alpha-amylase was found to be higher than the free enzyme, which may be due to interparticle diflusional mass transfer restrictions. The immobilized enzymes showed enhanced pH stability than the free enzyme. (c) 2006 Published by Elsevier B.V.