Arica, MYAlaeddinoglu, NGHasirci, V2020-06-252020-06-251998closedAccess0141-0229https://doi.org/10.1016/S0141-0229(97)00139-7https://hdl.handle.net/20.500.12587/2806Glucoamylase 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.eninfo:eu-repo/semantics/closedAccesspHEMA/EGDMA microspherescovalent bondingenzyme immobilizationglucoamylaseenzyme reactorArticle22315215710.1016/S0141-0229(97)00139-72-s2.0-0032520206Q1WOS:000071652100003Q2