Three‐dimensional numerical approach to investigate the substrate transport and conversion in an immobilized enzyme reactor

Abstract

This numerical study evaluates the momentum and mass transfer in an immobilized enzyme reactor. The simulation is based on the solution of the three-dimensional Navier-Stokes equation and a scalar transport equation with a sink term for the transport and the conversion of substrate to product. The reactor consists of a container filled with 20 spherical enzyme carriers. Each of these carriers is covered with an active enzyme layer where the conversion takes place. To account for the biochemical activity, the sink term in the scalar transport equation is represented by a standard Michaelis-Menten approach. The simulation gives detailed information of the local substrate and product concentrations with respect to external and internal transport limitations. A major focus is set on the influence of the substrate transport velocity on the catalytic process. For reactor performance analysis the overall and the local transport processes are described by a complete set of dimensionless variables. The interaction between substrate concentration, velocity, and efficiency of the process can be studied with the help of these variables. The effect of different substrate inflow concentrations on the process can be seen in relation to velocity variations. The flow field characterization of the system makes it possible to understand fluid mechanical properties and its importance to transport processes. The distribution of fluid motion through the void volume has different properties in different parts of the reactor. This phenomenon has strong effects on the arrangement of significantly different mass transport areas as well as on process effectiveness. With the given data it is also possible to detect zones of high, low, and latent enzymatic activity and to determine whether the conversion is limited due to mass transfer or reaction resistances.

Evaluation of hydromechanical and functional properties of diversion-type microcapsule-suspension bioreactor for bioartificial liver

“…9 A high void volume affects the mass transport between cells and the perfused fluid. 28 Bed expansion in DMFBB was significantly less than that in CFBB, indicating that void volume was less in DMFBB. With the lower void volume, microcapsules were allowed to achieve desirable fluidization in DMFBB, which reduced dead volume and improved the contact space and mixing efficiency between hepatocytes and the perfusion fluid.…”

A New Fluidized Bed Bioreactor Based on Diversion-Type Microcapsule Suspension for Bioartificial Liver Systems

“…We assessed the void volume with the bioreactor according to bed expansion. Void volume has previously been expressed as the dead volume in which there is no available access to cells [ 27 , 28 ], and a high void volume has an obvious effect on the mass transport between cells and the perfused solution [ 29 ]. We found that bed expansion in the DMFBB was significantly less than that in the conventional FBB, indicating the void volume was less in the DMFBB.…”

On the lattice Boltzmann method simulation of a two-phase flow bioreactor for artificially grown cartilage cells

“…The approach was used in the simulation of immobilized enzyme reactor (Esterl et al, 2003). Furthermore, the method was used to model reaction kinetics in nasal tissue and proved comparable results (Schroeter et al, 2005).…”