Adsorption of α-amylase in a fixed bed:: Operating efficiency and kinetic modeling

Kinetic studies on the adsorption of alpha-amylase from Aspergillus oryzae on the anion exchanger, Duolite A-568, and the hydrophobic resin, Duolite XAD-761, were carried out in a fixed bed. The efficiency with respect to the adsorbate and adsorbent was determined to estimate the performance of the process of adsorption. The effect of flow rate, alpha-amylase inlet concentration, temperature, and particle size of the packing was analyzed. In addition, the transient response, in the form of experimental breakthrough curves, was fitted using a phenomenological mathematical model accounting for the external-film and pore-diffusion mass-transfer mechanisms as well as axial dispersion along the column. Also, a Langmuir isotherm was included in the model to account for the extent of the equilibrium of adsorption. The model described satisfactorily the experimental breakthrough curves and it proved to predict successfully the behavior of a scaled-up bed using the kinetic and equilibrium parameters estimated previously. Thus, the mathematical model can be considered a reliable tool for process design and scale-up of similar systems.