On the use of apparent kinetic parameters for immobilized enzyme with noncompetitive substrate inhibition

Recent Developments in the Immobilization of Laccase on Carbonaceous Supports for Environmental Applications - A Critical Review

Τhe ligninolytic enzyme laccase has proved its potential for environmental applications. However, there is no documented industrial application of free laccase due to low stability, poor reusability, and high costs. Immobilization has been considered as a powerful technique to enhance laccase's industrial potential. In this technology, appropriate support selection for laccase immobilization is a crucial step since the support could broadly affect the properties of the resulting catalyst system. Through the last decades, a large variety of inorganic, organic, and composite materials have been used in laccase immobilization. Among them, carbon-based materials have been explored as a support candidate for immobilization, due to their properties such as high porosity, high surface area, the existence of functional groups, and their highly aromatic structure. Carbon-based materials have also been used in culture media as supports, sources of nutrients, and inducers, for laccase production. This study aims to review the recent trends in laccase production, immobilization techniques, and essential support properties for enzyme immobilization. More specifically, this review analyzes and presents the significant benefits of carbon-based materials for their key role in laccase production and immobilization.

Experimental evaluation of the usefulness of equations describing the apparent maximum reaction rate and apparent Michaelis constant of an immobilized enzyme reaction

To determine the usefulness of equations previously proposed for the apparent maximum reaction rate and apparent Michaelis constant of an immobilized enzyme, starch hydrolysis by glucoamylase immobilized on a porous ceramic support was considered as a model system. Initial reaction rates, v0, were measured for a wide range of initial starch concentrations, Sb0, to make a nonlinear plot of Sb0/v0 versus Sb0, and the apparent kinetic parameters were determined from the slopes and intercepts of tangents to the nonlinear plot at given values of Sb0. The equations were found to accurately express the diffusional effect on the kinetic parameters.