Capture of lactoferrin and lactoperoxidase from raw whole milk by cation exchange chromatography

Synthesis of a Cation-Exchange Resin by Inverse Suspension Polymerization for Lactoferrin Extraction from Whey

Lactoferrin (LF), the main iron-binding protein of milk, has important nutritional, biological, and pharmaceutical properties. It is an essential nutritional component of newborn diets and also for adult health. Small amounts of lactoferrin can be found in whey, a nutritionally and biologically useful byproduct of the dairy industry. Although the amount of lactoferrin in whey is less than that in other sources like milk and bovine colostrum, the extraction of LF from this underused source has many economic and environmental benefits. The most common technique for the isolation of LF from dairy products is the use of cation-exchange resins. Here, we present the synthesis of a strong cation-exchange resin for the extraction of high-purity lactoferrin from whey. This resin was synthesized by inverse suspension copolymerization of aqueous solutions of sodium 2-acrylamido-2-methyl-1-propanesulfonate and N,N-methylenebisacrylamide in corn oil. The adsorption efficiency of this resin showed selective extraction of lactoferrin from four different whey sources. The adsorption efficiency of lactoferrin from these whey samples ranged from 93.8 to 97.4%.

Separation Technologies for Whey Protein Fractionation

Whey is a by-product of cheese, casein, and yogurt manufacture. It contains a mixture of proteins that need to be isolated and purified to fully exploit their nutritional and functional characteristics. Protein-enriched fractions and highly purified proteins derived from whey have led to the production of valuable ingredients for many important food and pharmaceutical applications. This article provides a review on the separation principles behind both the commercial and emerging techniques used for whey protein fractionation, as well as the efficacy and limitations of these techniques in isolating and purifying individual whey proteins. The fractionation of whey proteins has mainly been achieved at commercial scale using membrane filtration, resin-based chromatography, and the integration of multiple technologies (e.g., precipitation, membrane filtration, and chromatography). Electromembrane separation and membrane chromatography are two main emerging techniques that have been developed substantially in recent years. Other new techniques such as aqueous two-phase separation and magnetic fishing are also discussed, but only a limited number of studies have reported their application in whey protein fractionation. This review offers useful insights into research directions and technology screening for academic researchers and dairy processors for the production of whey protein fractions with desired nutritional and functional properties.

Application of Ion Exchange and Adsorption Techniques for Separation of Whey Proteins from Bovine Milk

Background:

The world production of whey was estimated to be more than 200 million tons per year. Although whey is an important source of proteins with high nutritional value and biotechnological importance, it is still considered as a by-product of the dairy industry with low economic value due to low industrial exploitation. There are several challenges in the separation of whey proteins: low concentration, the complexity of the material and similar properties (pI, molecular mass) of some proteins.

Methods:

A narrative review of all the relevant papers on the present methodologies based on ion-exchange and adsorption principles for isolation of whey proteins, known to the authors, was conducted.

Results:

Traditional ion-exchange techniques are widely used for the separation and purification of the bovine whey proteins. These methodologies, based on the anion or cation chromatographic procedures, as well as combination of aforementioned techniques are still preferential methods for the isolation of the whey proteins on the laboratory scale. However, more recent research on ion exchange membranes for this purpose has been introduced, with promising potential to be applied on the pilot industrial scale. Newly developed methodologies based either on the ion-exchange separation (for example: simulated moving bed chromatography, expanded bed adsorption, magnetic ion exchangers, etc.) or adsorption (for example: adsorption on hydroxyapatite or activated carbon, or molecular imprinting) are promising approaches for scaling up of the whey proteins’ purification processes.

Conclusion:

Many procedures based on ion exchange are successfully implemented for separation and purification of whey proteins, providing protein preparations of moderate-to-high yield and satisfactory purity. However, the authors anticipate further development of adsorption-based methodologies for separation of whey proteins by targeting the differences in proteins’ structures rather than targeting the differences in molecular masses and pI. The complex composite multilayered matrices, including also inorganic components, are promising materials for simultaneous exploiting of the differences in the masses, pI and structures of whey proteins for the separation.

Lactoferrin concentration and expression in New Zealand cows milked once or twice a day

This study evaluated the concentration and expression of lactoferrin (LF) in cows selected for once a day (OAD) milking compared to twice a day (TAD) milking. Milk samples were collected from the Massey University TAD and OAD herds. Milk traits and expression of LF and insulin-like growth factor 1 (IGF-1) were analyzed with a general linear model that included the fixed effects of milking frequency, lactation number, interaction between milking frequency and lactation number, and as covariates proportion of F, heterosis F × J and deviation from the herd median calving date. Cows milked OAD produced milk with higher (p < .01) concentrations of protein and lactose than TAD milked cows. Compared to TAD cows, cows milked OAD had higher expression of the LF gene (1.40 vs. 1.29 folds, p = .03) and the IGF-1 gene (1.69 vs. 1.48 folds, p = .007). The correlation between the expression of LF gene and the concentration of LF in milk was strong (r = .66 p < .001), but the correlation between the expression of the IGF-1 gene and LF concentration was stronger (r = .94, p < .001). These results suggest that milking frequency affects the milk composition and expression of milk composition genes at early lactation.

Characterisation of Lactoferrin Isolated from Acid Whey Using Pilot-Scale Monolithic Ion-Exchange Chromatography

The aim of this study was to characterize the properties of lactoferrin (LF) obtained in a process developed for its isolation from acid whey derived from the production of fresh curd cheese, using a unique technology of ion-exchange chromatography on CIM® monolithic columns. The freeze-dried lactoferrin samples produced on the pilot plant (capacity 1 m3) were examined for the purity, iron-binding capacity, antibacterial activity, and pH- and temperature-stability. Apo-LF inhibited several tested strains (enterobacteria, Staphylococcus, Streptococcus salivarius) except clostridia, lactic acid bacteria, and bifidobacteria. Sample of LF intentionally saturated with Fe3+ lost its antibacterial activity, indicating the involvement of mechanisms based on depriving bacteria of an iron source. All samples, regardless of the iron-saturation level, exhibited stability in pH range 4.0 to 11.0. LF with higher iron content (A-value = 41.9%) showed better thermal stability. Heat treatment up to 72 °C/3 s did not reduce antimicrobial activity against E. coli O157: H7 tox-. Higher purity (above 91%), higher iron-binding capacity and higher inhibitory activity against E. coli O157: H7 tox- compared to some similar products from the market was observed. These results demonstrate a high potential of monolithic ion-exchange chromatography for industrial processing of acid whey as a source of LF that can be used in new products with high-added value. The upscaling of the process is ongoing on a demonstration plant (10–30 m3/day capacity).

Selective extraction of lactoferrin from acidic whey using CTAB/n-heptanol reverse micellar system

A reverse micellar system comprising CTAB/n-heptanol, developed for extracting lactoferrin (LF) from a synthetic solution of LF, was investigated for the selective extraction of LF from synthetic whey protein solution, which was prepared by mixing the pure whey proteins. The process conditions obtained during the process was further extended to extract the LF from real acidic whey. The selective extraction of LF was improved by studying the effect of NaCl concentration (additive) and aqueous phase pH on the partitioning of LF into the micellar phase. The highest extraction of LF (98.7%) from acidic whey to micellar phase was achieved at the aqueous phase pH of 10.3 and NaCl concentration of 1.1 M. The LF was back extracted to the aqueous stripping phase with 94% extraction efficiency and 100% purity. The recycling capacity of the organic phase after the back extraction of LF was analyzed to make the process more economical.

Tannins and Tannin-Related Derivatives Enhance the (Pseudo-)Halogenating Activity of Lactoperoxidase

Several hydrolyzable tannins, proanthocyanidins, tannin derivatives, and a tannin-rich plant extract of tormentil rhizome were tested for their potential to regenerate the (pseudo-)halogenating activity, i.e., the oxidation of SCN^- to hypothiocyanite ^-OSCN, of lactoperoxidase (LPO) after hydrogen peroxide-mediated enzyme inactivation. Measurements were performed using 5-thio-2-nitrobenzoic acid in the presence of tannins and related substances in order to determine kinetic parameters and to trace the LPO-mediated ^-OSCN formation. The results were combined with docking studies and molecular orbital analysis. The ^-OSCN-regenerating effect of tannin derivatives relates well with their binding properties toward LPO as well as their occupied molecular orbitals. Especially simple compounds like ellagic acid or methyl gallate and the complex plant extract were found as potent enzyme-regenerating compounds. As the (pseudo-)halogenating activity of LPO contributes to the maintenance of oral bacterial homeostasis, the results provide new insights into the antibacterial mode of action of tannins and related compounds. Furthermore, chemical properties of the tested compounds that are important for efficient enzyme-substrate interaction and regeneration of the ^-OSCN formation by LPO were identified.

Production of human lactoferrin in animal milk

Genetic constructs containing the human lactoferrin (hLf) gene were created within a joint program of Russian and Belorussian scientists. Using these constructs, transgenic mice were bred (the maximum hLf concentration in their milk was 160 g/L), and transgenic goats were also generated (up to 10 g/L hLf in their milk). Experimental goatherds that produced hLf in their milk were also bred, and the recombinant hLf was found to be identical to the natural protein in its physical and chemical properties. These properties included electrophoretic mobility, isoelectric point, recognition by polyclonal and monoclonal antibodies, circular dichroic spectra, interaction with natural ligands (DNA, lipopolysaccharides, and heparin), the binding of iron ions, the sequence of the 7 terminal amino acids, and its biological activity. The latter was assessed by the agglutination of Micrococcus luteus protoplasts, bactericidal activity against Escherichia coli and Listeria monocytogenes , and fungicidal activity against Candida albicans . We also demonstrated a significant increase in the activity of antibiotics when used in combination with Lf.

The influence of major components on the direct chromatographic recovery of a protein from transgenic milk

This work presents a systematic evaluation of the influence of lipids and casein on the performance of a chromatographic capture step for the recovery of a target protein from transgenic milk. Lactoperoxidase (LPO) was spiked at concentrations typical of those to be expected for transgenic proteins in commercial bovine milk and the dynamic adsorption of LPO to fixed beds of SP Sepharose FF studied in frontal analysis experiments. By removing successively selected components from whole milk, their individual influence on the dynamic adsorption behaviour of LPO could be studied. A mathematical model, fitted to the breakthrough curves of LPO, provided a quantitative measure of parameters describing mass transfer and adsorption in the column. A significant reduction in column capacity for LPO in the presence of milk or whey was recorded, which could be attributed to competing adsorption of alkaline earth metal ions to the cation exchange resin. While the high concentrations of lipids present in whole milk did strongly reduce the column permeability, no significant influence of either casein or low concentrations of lipids on the hydraulic properties of columns or on the adsorption of LPO could be detected. The results indicate that chromatography, which forms an essential part of all current large-scale processes for the recovery of proteins from transgenic milk, could potentially be moved further upstream. Alternatively, existing operations for the removal of lipid and casein could be re-designed so as to maximise product yields. This suggests that significant product losses during current pre-chromatography milk purification could be reduced or potentially even avoided.