Separation of transforming growth factor-beta2 (TGF-β2) from whey protein isolates by crossflow microfiltration in the presence of a ligand

The effects of pH adjustment, ionic strength and adding lambda-carrageenan (λ-CG) to whey protein isolate (WPI) solutions on the transmission of transforming growth factor-beta2 (TGF-β2) through a 0.8 μm pore size microfiltration (MF) membrane were investigated. Increasing pH (7–9) or adding NaCl (0.1 M) increased both the transmission of proteins and TGF-β2. Adding 0.01% λ-CG to WPI solutions decreased both the transmission of proteins and TGF-β2 and increased membrane fouling. The highest membrane selectivity (0.28) and concentration factor (1.67) for TGF-β2 were obtained at neutral pH conditions without NaCl or λ-CG. The addition of λ-CG allowed the preparation of a retentate slightly enriched in TGF-β2 but also in immunoglobulins.