KINETICS OF FRUCTOSE-GLUCOSE ISOMERIZATION WITH SWEETZYME TYPE-A

A study has been made of the kinetics of fructose-glucose enzymatic is omerization with an immobilized glucose isomerase, Sweetzyme A, at 60 degrees C and with initial fructose concentrations of between 0.1 and 2.0 M. In the kinetic study, the effects of internal and external tran sport were considered, and it was found that when the data were fitted to a kinetic of a pseudo-first-order type, the non-enzymatic reaction could not be disregarded at low enzyme and high substrate concentrati ons. When non-enzymatic isomerization is taken into account, the true enzymatic-reaction constant can be calculated, giving values for maxim um rate of 1.39.10(-6) mol (kg.s)(-1) and for Michaelis-Menten constan t of 1.24 M. Establishing the influence of the transport in the interi or of the catalyzing particles has enabled the determination of a valu e for effective diffusivity of 0.59.10(-10) m(2).s(-1).