Immobilization of glucoamylase onto activated pHEMA/EGDMA microspheres: properties and application to a packed-bed reactor

• Published in: Enzyme and microbial technology 1998-02, Vol.22 (3), p.152-157
• Main Authors: Arica, M.Yakup, Alaeddinoğlu, N.Gürdal, Hasirci, Vasif
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Bioreactors; Biotechnology; Chemical bonds; covalent bonding; enzyme immobilization; enzyme reactor; Fundamental and applied biological sciences. Psychology; glucoamylase; Immobilization of enzymes and other molecules; Immobilization techniques; Methods. Procedures. Technologies; Packed beds; pHEMA/EGDMA microspheres; Polyacrylates
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/S0141-0229(97)00139-7

Glucoamylase was covalently immobilized onto pHEMA/EGDMA microspheres of two different sizes: 50–100 μm and 100–200 μm in diameter. The activity of the enzyme on smaller microspheres was found to be almost twice that of the larger microspheres. A higher enzyme loading was observed on small microspheres (0.64 mg g −1 support) as compared to large spheres (0.40 mg g −1 support). The K m of glucoamylase was significantly increased (approximately five times) upon immobilization, indicating decreased affinity by the enzume for its substrate. V max of the enzyme was, however, not as significantly altered upon immobilization as the K m. More significantly, the V max was much higher with the large substrate (dextrin) than it was with the small substrate (maltose). Activity of the immobilized enzyme was quite stable. In 120 h, only 9.0% of the immobilized glucoamylase activity was lost.