Abhiram Arunkumar - Fractionation of alpha-lactalbumin and beta-lactoglobulin from bovine milk serum using staged positively charged tangential flow ultrafiltration membranes

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      Publication Details (including relevant citation   information):

      A. Arunkumar, M.R.Etzel (2014), J. Membr. Sci., 454, 488


    1.         Fractionation of bovine a-lactalbumin     (ALA) from b-lactoglobulin     (BLG) in
          milk serum permeate (MSP) using tangential flow ultrafiltration     was examined in
          this work. By placing a positive charge on a 300 kDa     regenerated cellulose
          ultrafiltration membrane, it was possible to increase the     selectivity for
          fractionating ALA and BLG by 180 % compared to an uncharged     membrane. Thus,
          like-sized proteins that differed only somewhat in isoelectric     point, and that
          were about 15-20 times smaller than the membrane molecular     weight cutoff, were
          fractionated using charged ultrafiltration membranes.     Electrostatic repulsion
          was solely responsible for the improved selectivity. Protein     sieving
          coefficients were explained by the net charge on the protein     and the stagnant
          film model. From experimental data using a single-stage system     under total
          recycle conditions, mass balance models were used successfully     to predict the
          performance of a multi-stage membrane system. A three-stage     system gave 87 %
          pure ALA and 83 % pure BLG. Thus, dairy protein fractions of     chromatographic
          purity can be obtained using charged ultrafiltration membranes     arranged in
          stages, without the wastewater generation and expense of     chromatography. The
          results of this study will be useful for expanding the utility     of
          ultrafiltration membranes beyond simple protein concentration     to fractionation
          of proteins.

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