Electroseparation of bovine lactoferrin from model and whey solutions

Bovine lactoferrin (LF), a 80 kDa iron-binding glycoprotein, has been reported to have important nutraceutical and biological properties such as anti-inflammatory, antimicrobial and immunostimulatory activities. However, the large scale utilisation of LF requires a cost-effective purification process. The aim of this study was to evaluate the feasibility of separating lactoferrin from whey using electrodialysis with an ultrafiltration membrane (EDUF) system and to study the effect of pH on this protein migration rate during EDUF treatments. Initially, to set the optimum conditions for electroseparation of this molecule, its electrophoretic mobility was measured according to the pH (pH 3–12). LF had an optimal electrophoretic mobility at pH 3.0 of 1.5 × 10−8 m2 V−1 s−1 in a 2 g/L KCl solution and of 3.0 × 10−8 m2 V−1 s−1 in distilled water. Thereafter, a 0.1% LF solution at pH 3.0 was treated by EDUF with an ultrafiltration membrane of 500 kDa molecular weight cut-off. A migration rate going up to 46% was obtained after 4 h of treatment. Finally, the EDUF process was applied on lactoferrin-enriched-whey solutions at pH values of 3.0, 4.0, and 5.0. The highest migration rate for lactoferrin was obtained at pH 3.0 with a migration yield of 15%. Thus, it appeared that the EDUF process could allow the separation of large proteins, such as LF, from a solution. Furthermore, the selectivity of EDUF was decreased in whey solution due to concomitant migration of β-lactoglobulin or other whey proteins. However, the fraction obtained at pH 3.0 presented β-lactoglobulin percentages close to the ones obtained for WPI by ion-exchange technology.