Reverse Micellar Extraction of Lactoferrin from Whey

Abstract

Whey, the by-product of dairy industry, contains variety of nutritional valued and commercially important biomolecules. Lactoferrin (LF) is one among the whey protein, present in very less concentration in whey and other biological sources like, saliva, tears, synovial fluid. LF has wide applications in medicinal field as anticancer agent, antiviral activity, maintaining iron level in the body. It is a major component of infant formula and also used in various oral care products and cosmetics. All the mentioned applications require the LF in reasonable amount with high purity. The market demand of LF increased to 262,000 kg in 2017 with the cost ranging from US$500 to US$1,000 per kilogram depending on the purity. The existing technologies/methods used for extraction of LF with required purity are failed to meet the market demand. As an alternative, the reverse micellar extraction (RME), a bulk extraction process, has been developed in the present study for the selective extraction of LF from whey. The reverse micellar system (RMS) formed by CTAB/n-heptanol was identified for the selective extraction of LF by considering different types of surfactants and solvents. The selected RMS was studied to identify the suitable process condition for the solubilisation of LF in the reverse micellar phase and their effect on the extraction efficiency by conducting the experiments systematically. Initially, the influence of surfactant type, types of salt, phase components and their concentration, pH, cosolvents and phase volume ratio on the forward and back extraction of LF was studied using commercially available LF. The optimised process conditions were then extended to selectively extract the LF from acidic whey. Maximum forward extraction of 98.7% was achieved for LF in CTAB/n-heptanol reverse micellar system at CTAB concentration of 50mM, salt concentration 1.1M and maintaining aqueous phase pH 10.3. Whereas, 94.2% LF was back extracted without any impurities at stripping phase pH 6, 1.5M KCl and 7% n-butanol as a co-solvent. The recycling capacity of the spent reverse micellar phase was studied at optimized extraction condition and the reverse micelle phase may be recycled at least three times without much loss in their extraction capacity. The feasibility of continuous operations of the RME process has also been demonstrated in Rotating Disc Contactors by studying the effect ofvariables like rotor speed, dispersed RM phase and aqueous phase velocities on the extraction characteristics.