The enzyme leakage of alginate/K-carrageenan beads containing cross-linked lipase was compared to that of lipase entrapped in same hybrid matrix without cross­linking by modifying the method of Wu et al. (2007). Both the types of beads were incubated at 25°C, 200 rpm in 0.01 M phosphate buffer of pH 7 soon after bead formation. The enzyme leakage was done by withdrawing the buffer every 1 h and recording the absorbance at 280 nm using a UV-vis spectrophotometer.

The enzyme leakage from immobilized lipase with and without glutaraldehyde cross-linking is plotted against time and is shown in Fig. 12.5a. It was observed that 65.76% reduction in enzyme leakage was observed from the hybrid beads after cross-linking as compared to that from non-cross-linked beads. Thus, it is under­stood that cross-linking with glutaraldehyde followed by entrapment in hybrid matrix can significantly reduce enzyme leakage. The reasons for the reduced enzyme leakage can be attributed to the increased molecular weight of the cross — linked enzyme and efficient interaction of enzyme moieties with the polymers of alginate and K-carrageenan.