Characteristics of immobilized bacterial D-hydantoinase on alginate

D-hydantoinase (E.C.: 3.5.2.2) was isolated form Bacillus theorgensis. The enzyme activity was enhanced by Triton-X100 and Tween-20. ATP up to 8 mM activated the enzyme activity in concentration-dependent manner. The enzyme was inhibited by EDTA, o-phenanthroline, ?-dipyridyl and hydroxyquinoline. EDTA was the weakest chelating agent. C50 for the other three compounds were 6.5, 4, and 3.3 mM. D-hydantoinase was activated by Cu2+, Mn2+, Mg2+, Fe2+, Zn2+, Co2+, Ca2+ and Ni2+. Ca2+ was the best activator. However, the enzyme was inhibited by Cu2+ and Fe2+. The enzyme was immobilized on alginate beads. Increasing sodium alginate concentration up to 3% (w/v) resulted in continuous increase of immobilization yield. The optimal time of immobilization was 5h. Increasing of CaCl2 concentration up to 3% (w/v) resulted in corresponding increase in the immobilization yield. Potassium phosphate buffer at 150 mM was better than Tris-HCl buffer for enzyme immobilization.