Improved yield and stability of amylase by multipoint covalent binding on polyglutaraldehyde activated chitosan beads: Activation of denatured enzyme molecules by calcium ions |
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Authors: | Tochukwu Nwamaka Nwagu Bartholomew Okolo Hideki Aoyagi Shigeki Yoshida |
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Institution: | 1. Life Sciences and Bioengineering, Graduate School of Life and Environmental Sciences, University of Tsukuba, Japan;2. Department of Microbiology, Faculty of Biological Sciences, University of Nigeria, Nsukka, Nigeria |
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Abstract: | In this study raw starch digesting amylase (RSDA) from Aspergillus carbonarius (Bainier) Thom IMI 366159 was stabilized by covalent binding on polyglutaraldehyde (PG), glutaraldehyde (G) activated chitosan beads or post immobilization cross linking of enzyme adsorbed on chitosan. Presence of Ca2+ ions (0.5–1.5 mM) activated the PG and G derivatives but repressed the crosslinked enzyme. Optimum pH for cross linked derivative increased by 2 units but was unaltered for PG and G derivatives. Immobilized amylase exhibited improved thermal and storage stability. Immobilized derivatives had no loss of activity after 1 month storage and retained above 90% activity after 10 batch reactions of 60 min each. Immobilization successfully stabilized RSDA and immobilized enzyme from A. carbonarius can be applied in numerous industries for cheap, cost effective and environmentally friendly starch hydrolytic processes to simple sugars. |
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Keywords: | Raw starch digesting Immobilization Amylases Stabilization Glutaraldehyde Covalent linkages |
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