Optimal Kinetic Parameters and Batch Modeling for Pectin Hydrolysis to Galacturonic Acid with Pectinex Ultra SP-L Enzyme

摘要

Galacturonic acid is a monosaccharide obtained by pectin hydrolysis and a suitable substrate to produce bioethanol by fermentation. This article focuses on quantification of citrus pectin hydrolysis to galacturonic acid and provides new, reliable kinetic parameters for the Michaelis-Menten equation when the well-known commercial Pectinex Ultra SP-L is employed as enzyme. They are: r_(max) = 1.10 g/(L min), K_m = 10.42 g/L, and K_(IGA) = 10.05 gjL, as obtained with a great accuracy by a nonlinear regression method and confirmed by the three classical linearization procedures (Lineweaver-Burk, Langmuir, and Eadie-Hofstee). The quantification of product inhibition has been achieved, with its inclusion in the rate equation. A batch reactor model yields perfect agreement between predictions and experiments, even under conditions different from those on which the parameters had been determined by regression.