Heterogeneous one-dimensional model for fixed bed enzyme reactors

Biochemical engineering of biocatalysts immobilized on cellulosic materials

Complete design of the optimum immobilized biocatalyst seems to still be a matter of the future. To be successful, it would require numerical determination of all significant parameters at each enzyme engineering phase, that is at the design of the carriers, immobilized biocatalysts and immobilized reactors. Future research trends should follow this strategy. For processing, cellulosic materials have been considered carriers that fulfill requests to an example model: they represent a unique family of carriers that cover a broad variety of physical and chemical properties, immobilizing techniques, and immobilized reactors as well. The reason for writing this review article was to test the reliability of such a processing and subsequently, to confront theoretical considerations with practical applications of biocatalysts immobilized on cellulose materials.

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

The use of a simple rate equation with apparent parameters to describe the kinetic behavior of an immobilized enzyme with uncompetitive [corrected] substrate inhibition was assessed. To do so, the reaction rate was calculated as a function of the interfacial substrate concentration, and the results were used to identify the apparent kinetic parameters by nonlinear regression. This procedure was repeated for different values of the diffusional constraints and of the inhibition constant. The equation using apparent parameters can describe the global kinetic behavior, provided that the diffusional and inhibitory constraints are not too high. When the constraints are high, a Michaelis-Menten equation can be used to model the kinetics for interfacial concentrations lower than the concentration leading to the maximum reaction rate.