Simulation of stirred tank affinity processes applied to separation of proteins

A model, which includes pore diffusion, external film resistance, and finite kinetic rate, was used to mathematically describe a batch affinity adsorption system. The corresponding differential equations system was solved using two numerical methods: the numerical method of lines (NUMOL) and the global (implicit) finite difference method. In each case, simulation studies were conducted to determine the mass-transfer-controlled mechanism. Experimental data from literature describing batch affinity adsorption of immunoglobulin G to protein A-Sepharose was used as a model system. The best fit of the experimental data was obtained with the mass-transfer process controlled by pore diffusion and film resistance, in the simulation studies, using the NUMOL solution. The transport model was used to perform a parametric analysis of the experimental batch system. The influence of both process parameters as well as physical parameters on the affinity adsorption process was investigated.