Application of foam separation processes for protein extraction/stripping

The present work examines the foaming characteristics of four well characterised model proteins, in a semi-batch operation. The critical micelle concentration (CMC) value of these proteins was determined by surface tension measurements and was found to be dependent on the physicochemical characteristics of the protein molecule. Protein solutions at initial concentrations higher than CMC value were sparged with air in the separation column. The protein concentration in foam was maximum for β-lactoglobulin, followed by bovine serum albumin (BSA), α-lactalbumin and β-casein. The protein concentration in the residual solution was minimum for BSA, followed by α-lactalbumin, β-casein and β-lactoglobulin. Separation of BSA was carried out both in semi-batch and continuous operation mode. It was shown that higher enrichment (about twice that of semi-batch) is achievable if the process is operated continuously. There was also slight enhancement in protein recovery with continuous processing.