Continuous degradation of maltose by enzyme entrapment technology using calcium alginate beads as a matrix

摘要

Maltase from Bacillus licheniformis KIBGE-IB4 was immobilized within calcium alginate beads using entrapment technique. Immobilized maltase showed maximum immobilization yield with 4% sodium alginate and 0.2M calcium chloride within 90.0min of curing time. Entrapment increases the enzyme–substrate reaction time and temperature from 5.0 to 10.0min and 45°C to 50°C, respectively as compared to its free counterpart. However, pH optima remained same for maltose hydrolysis. Diffusional limitation of substrate (maltose) caused a declined in V max of immobilized enzyme from 8411.0 to 4919.0Uml ?1 min ?1 whereas, K m apparently increased from 1.71 to 3.17mMml ?1 . Immobilization also increased the stability of free maltase against a broad temperature range and enzyme retained 45% and 32% activity at 55°C and 60°C, respectively after 90.0min. Immobilized enzyme also exhibited recycling efficiency more than six cycles and retained 17% of its initial activity even after 6th cycles. Immobilized enzyme showed relatively better storage stability at 4°C and 30°C after 60.0 days as compared to free enzyme. Graphical abstract Display Omitted Highlights ? Immobilized maltase showed maximum immobilization yield with 4% sodium alginate and 0.2M calcium chloride. ? Immobilized maltase showed maximum relative activity with 2.0mm beads size. ? Immobilization also increased the stability of free maltase against a broad temperature range. ? Immobilized enzyme also exhibited admirable recycling efficiency up to 06 reaction cycles that retained 17% of its initial activity even after six cycles.