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A Comparative study of different immobilization techniques for immobilization
A Comparative study of different immobilization techniques for immobilization cyclodextrin
glucosyltransferas from Bacillus amyloliquefaciens
Reyed M.Reyed
CGTase from Bacillus amyloliquefaciens was immobilized on various carriers by different techniques of immobilization. the coupled enzyme had higher immobilization yield on chitin (53.6 %), Amberlite IRA.-45 (14.26 %), Duolite AM 761 (59.19%) and polyacrylamide (50.6 %). The enzymatic properties of bound CGTase were investigated and compared with those of the unbound ones . The optimal pH of the immobilized enzymes were shifted to more acidic range (pH 5.0) for chitin, Amberlite IRA-45, and polyacrylamide, and (pH 6.0) Duolite AX1761 compared to the free enzyme that has an optimum (pH 6.5). The pH stability of the immobilized enzymes was shifted to more acidic range (pH 4.0-8.0), compared to the free enzymes (5.5-8.5). The optimal reaction temperature of the enzyme was shifted from 58 for free enzymes to 63, 66, 70, and 68 °C for enzymes immobilized on chitin, Amberlit IRA 45, Duolite AXI 761 and polyacrylamide were respectively. The activation energy (Ea) for free and immobilized enzyme on chitin, Amberlite IRA 45, Duolite AXI 761 and polyacrylamide were 3.32, 3.7, 3.96, 1.66 and 2.25 kcal /mol. respectively. The thermal stability of the free and immobilized was investigated at 50-80 °C. The half-life (t1/2) for free enzyme at 60 and 70 °C are lower than those of the immobilized enzymes. This study show that immobilized enzymes on duolite AXI 761 more thermal stable than other carriers. The Kmax values of the immobilized Genetic Eng. & Biotechnology Research Institute, Mubarak city for scientific research and applied technology. New Borg El-Arab, Post code 21934, Alexandria, Egypt. Tel. -02-03-4593421, Fax. -00203-459423. e. mail: reyed@bio.la & rmrkater@mail.ru
Published: December 25, 2006
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