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 °C with relative insensitivity to temperatures up to 80 °C. Crosslinked enzyme lost 4% residual activity, whereas soluble enzyme lost over 50% activity after 12 h incubation at 60 °C. PG activated derivative showed an apparent Km of 0.29 mg/mL, whereas the crosslinked enzyme showed an apparent Km 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 crosslinked 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.

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► Immobilization of raw starch digesting amylase (RSDA) on glutaraldehyde functionalized and non-functionalized sepa bead.
► Optimum pH and temperature was altered by 1 unit due to immobilization.
► Crosslinking of enzyme adsorbed on non-functionalized beads was most thermoactive and thermostable.
► A slight variation in the kinetic constant of free and bound enzyme was observed.
► Immobilization remarkably improved storage and operational stability of the RSDA.