Characterization of immobilized post-carbohydrate meal salivary α-amylase

Abstract

Saliva containing amylase was collected from an individual 5 min after a carbohydrate meal and filtered using a dialysis bag to remove starch particles. The filtered saliva was immobilized on calcium alginate beads. The effect of experimental parameters like pH, temperature and substrate concentration on the activity of the immobilized post-carbohydrate meal salivary α-amylase was determined. The immobilized salivary α-amylase had an optimum activity at temperature 40°C and pH 7.0. The activation energy (Ea) as obtained from the Arrhenius plot was 31.4 kJ/Mol. The kinetic parameters Km and Vmax of the immobilized α-amylase were found to be 1.6 mg/ml and 16.4 μmol/min, respectively; this was compared to that of free salivary α-amylase (Km = 0.0048 mg/ml) and α-amylases from fungi and bacteria sources. Immobilization tends to increase the Km of the immobilized enzyme, indicating a low affinity for substrate, however the enzymes Km was lower than that of some microbial α-amylases. The results obtained from the characterization of immobilized post-carbohydrate meal salivary α-amylase in this study show that immobilization had no significant effect on the enzyme and compared to kinetic parameters of microbial α-amylase, immobilized salivary α-amylase may not be of significant benefit as alternative source of α-amylase in the industrial bioprocesses.

Key words: Enzyme activity, carbohydrate, immobilized enzyme, industrial bioprocess, kinetics, salivary α-amylase.

Abbreviation: Ea, Activation energy.