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

Abstract

Maltase from <i>Bacillus licheniformis</i> KIBGE-IB4 was immobilized within calcium alginate beads using entrapment technique. Immobilized maltase showed maximum immobilization yield with 4% sodium alginate and 0.2 M calcium chloride within 90.0 min of curing time. Entrapment increases the enzyme-substrate reaction time and temperature from 5.0 to 10.0 min 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 <i>V</i>_<i>max</i> of immobilized enzyme from 8411.0 to 4919.0 U ml^-1 min^-1 whereas, <i>K</i>_<i>m</i> apparently increased from 1.71 to 3.17 mM ml^-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 90.0 min. 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.