A kinetic model for the pectin hydrolysis using an endo-acting pectinase from Rhizopus

Abstract Enzyme kinetics of pectin hydrolysis reaction catalysed by an endo -polygalacturonase from Rhizopus have been analysed experimentally in a stirred batch reactor at pH=4.5 and T =34°C using a sodium salt of polygalacturonic acid as substrate. The reaction products, consisting of oligomers of galacturonic acid, were classified in four classes of oligomeric fractions employing three hollow fibre ultrafiltration units characterised by different molecular weight cut-off ( MW co ). On the basis of the time-concentration data, a kinetic model of the reacting system has been proposed in terms of a series-side reaction pattern. Identification of kinetic parameters was carried out by a non-linear regression optimization procedure based on the Powell's algorithm of conjugated directions. Finally, the kinetic model was used to predict the best reactor configuration able to control the product distribution for a given enzyme/substrate concentration ratio.