Immobilization of a saccharifying raw starch hydrolyzing enzyme on functionalized and non-functionalized sepa beads

Raw starch digesting amylase (RSDA) was immobilized onto functionalized and non-functionalized sepa beads using the bifunctional agent, glutaraldehyde. The immobilization yield for polyglutaraldehyde (PG) activated and crosslinked RSDA was 97% and 86%, respectively. The optimum pH of the enzyme changed from 5 to 6. The optimum temperature of the immobilized enzyme increased from 30 to 60 degrees C with relative insensitivity to temperatures up to 80 degrees C. Crosslinked enzyme lost 4% residual activity, whereas soluble enzyme lost over 50% activity after 12 h incubation at 60 degrees C. PG activated derivative showed an apparent K-m of 0.29 mg/mL, whereas the crosslinked enzyme showed an apparent K-m of 0.54 mg/mL. The immobilized enzyme showed high operational stability by retaining 92% and 100% of initial activity after 10 uses for PG activated and crosslinkecl derivatives, respectively. The use of a cheap carrier coupled with the easy immobilization protocol and the increased stabilization shows that this method is suitable for RSDA. Immobilization of RSDA therefore improves the properties of the enzyme and broadens its scope for utilization in bio-processes involving starch saccharification and even in bio-analytical operations and drug designs with reduced cost and time. (C) 2012 Elsevier B.V. All rights reserved.