(305c) Rapid Characterization of Membrane Fouling by Proteins in Constant Flux Microfiltration and Development of Mathematical Model for Fouling Prediction

Fouling of microfiltration membranes by proteins is a major challenge in bioprocessing. It is affected by a diverse range of factors: operating condition such as permeate flux and system hydrodynamics, protein solution properties such as pH, ionic strength and protein concentration, and membrane properties such as hydrophilicity, roughness, pore size and distribution. Knowledge of protein fouling mechanisms is essential for prediction, control and prevention of fouling. We discuss a technique for rapid assessment and characterization of fouling during constant flux microfiltration of protein solutions. This technique is based on the pulsed sample injection technique for fouling assessment, earlier developed in our group for studying fouling of ultrafiltration membranes. Different stages of fouling are identified form the transmembrane pressure-time (TMP-time) profiles in microfiltration tests. The initial fouling rate is found to be slow from which there is transition to a rapid fouling stage followed by a slow fouling stage. A multi-mechanism mathematical model which takes into account pore blockage, cake formation and pore constriction are discussed. The model predictions are compared with experimental results.