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

Arica M., Alaeddinoglu N., Hasirci V.

ENZYME AND MICROBIAL TECHNOLOGY, vol.22, no.3, pp.152-157, 1998 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 22 Issue: 3
  • Publication Date: 1998
  • Doi Number: 10.1016/s0141-0229(97)00139-7
  • Page Numbers: pp.152-157


Glucoamylase was covalently immobilized onto pHEMA/EGDMA microspheres of two different sizes: 50-100 mu m and 100-200 mu m in diameter. The activity of the enzyme on smaller microspheres was found to be almost twice that of the larger microspheres. A higher enzyme lending 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 enzyme 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. (C) 1998 Elsevier Science Inc.