Modelling of a fluidized bed bioreactor for immobilized enzymes. Part 1.

A mathematical model is presented for a liquid fluidized bed bioreactor using industrial glucose isomerase. The enzymes are immobilized onto 3 different fractions of a high porous SiO sub 2 carrier with defined biocatalysts is calculated by a numerical routine. For the calculation of the concentration profile inside the reactor, a semi-analytical solution is derived, which takes into account the height dependence of the effectiveness factor. Experiments with native and immobilized enzymes were carried out in stirred tank reactors, in order to evaluate the kinetic parameters. The influence to external mass transfer was investigated in a fixed bed reactor column. The extend of pore diffusional resistance was examined in a continuous stirred tank and with a numerical solution. Hydrodynamics was measured in different reactor columns (diameter: d sub t = 0.025 - 0.225 m; length: l = 1.0 - 2.0 m) and with a static mixer. The concentration profile was determined in a fluidized bed reactor wit h side stream analysis for different biocatalyst samples, fluid velocities and bed heights. The simulation of experimental results indicates that they are well described by the developed model. Furthermore the influence of specific parameters upon the effective kinetics of the biocatalyst and the expansion of the fluidized bed can be well predicted by the model