Electric field enhanced fractionation of protein mixture using ultrafiltration

Electric field enhanced cross-flow ultrafiltration has been carried out for fractionation of aqueous solution of two proteins, e.g., bovine serum albumin (BSA) and Lysozyme using a 30 kg/mol molecular weight cut-off membrane. A detailed parametric study has been carried out to investigate the effect of system parameter such as electric field, solution pH, feed concentration ratio, cross-flow velocity and pressure difference on the permeate flux and observed retention of Lysozyme. A theoretical model based on film theory is developed to predict permeate flux and observed retention of Lysozyme under laminar flow regime including the effects of external d.c. electric field for osmotic pressure governed ultrafiltration. The governing equations of the concentration profile in the developed mass transfer boundary layer in a rectangular channel are solved numerically. The model parameters such as real retention (R-r2) of the Lysozyme and protein-protein interaction parameter (B) are evaluated by optimizing the experimental values of steady state permeate flux and permeate concentration. The experimental results reveal that there is a significant effect of electric field on both permeate flux and observed retention. (C) 2009 Elsevier B.V. All rights reserved.