Modelling of potato starch saccharification by an Aspergillus niger glucoamylase

The kinetics of hydrolysis of a soluble potato starch catalysed by free glucoamylase was investigated in a batch reactor. Seventeen progress curves of product concentration, obtained at varying initial substrate and enzyme concentrations, were fitted simultaneously using six different models of saccharification process. A good description of the whole course of the progress curves was obtained using a six-parameter model based on a kinetic equation, which contained product and substrate inhibition terms. An essential feature of the model was that starch was structured into susceptible and resistant fractions that differed in the rate constants of hydrolysis. The model parameters were estimated with a good accuracy and were in a good agreement with the available literature information. (C) 2003 Elsevier B.V. All rights reserved.