Bioaffinity immobilization and characterization of α-galactosidase on aminophenylboronicacid derivatized chitosan and Sepabeads EC-EA

Enzyme immobilization with affinity binding which is based on the specific affinity interactions have an important advantage as; high selectivity. In the present study, chitosan and Sepabeads EC-EA were derivatized with aminophenylboronicacid(APBA) for the affinity immobilization of α-galactosidase. The influence of various process parameters on immobilization of the enzyme is investigated to get high immobilization yields. Under optimized immobilization conditions, the chitosan and Sepabeads EC-EA immobilized enzymes exhibited activity yield of 89.5% and 72%, respectively. The maximum activities were detected at 40 °C for free and Sepabeads EC-EA immobilized enzyme and 55 °C for chitosan immobilized enzyme. The optimum pH was found as pH 5.0 for free and Sepabeads EC-EA immobilized enzyme and pH 5.5 for chitosan immobilized enzyme. Both immobilized enzymes were very stable at temperature ranged from 4 to 55 °C and also in a pH range of 2.6-7.0. The immobilized α-galactosidases were also used in the hydrolysis of raffinose. The chitosan and Sepabeads EC-EA immobilized enzymes hydrolysed 55% and 42% of raffinose in 32 h at 50 °C, respectively. The obtained results shed light for the useability of these immobilized enzymes in the hydrolysis of raffinose in food industry and make these immobilized enzymes good candidates for their various biotechnological applications.