Separation of protein mixtures by an integrated electro-ultrafiltration–electrodialysis process

An integrated process for improving selectivity and permeate flux in ultrafiltration based protein fractionation was developed by combining electrodialysis (ED) with electro-ultrafiltration (EUF). The performance of such a process was first investigated using individual proteins (bovine serum albumin and lysozyme) and then with a mixture of the two. The experimental results showed that as with EUF on its own, the build-up of lysozyme concentration polarization near the cation exchange membrane in the permeate compartment significantly affected ion migration and led to change in pH and conductivity of the feed solution during an EUF–ED process with lysozyme, or bovine serum albumin and lysozyme mixture. As compared with EUF, EUF–ED of protein mixture resulted in a 20% increase in permeate flux with the lysozyme transmission remaining the same. The demineralization that occurred during EUF–ED made this process suitable for protein separation from the feed solutions with high conductivity.