Large scale extraction of alpha-lactalbumin and beta-lactoglobulin from bovine whey by precipitation with polyethylene glycol and partitioning in aqueous two-phase systems

Purification of α-lactalbumin and β-lactoglobulin from cow milk

Whey, a valuable byproduct of dairy processing, contains essential proteins like β-lactoglobulin (βLG) and α-lactalbumin (αLA), making it a focus of research for its nutritional benefits. Various techniques, including chromatography and membrane filtration, are employed for protein extraction, often requiring multiple purification steps. One approach that has gained prominence for the purification and concentration of proteins, including those present in whey, is the use of polyethylene glycol (PEG) in aqueous two-phase systems. Our study simplifies this process by using PEG alone for whey protein purification. This approach yielded impressive results, achieving 92 % purity for βLG and 90 % for αLA. These findings underscore the effectiveness of PEG-based purification in isolating whey proteins with high purity.

Purification of bovine alpha-lactalbumin by immobilized metal ion affinity chromatography

The milk protein alpha-lactalbumin was isolated from bovine whey protein concentrate solution by immobilized metal ion affinity chromatography (IMAC) using Cu(II)-Chelating Sepharose Fast Flow. Stepwise pH (5.5-3.8) changes in sodium acetate buffer were used to elute the protein selectively, at which time it was concentrated and reapplied to an uncharged Chelating Sepharose Fast Flow column to remove the contaminating Cu(II) ions. A purity of 90% and recovery of 80% was achieved. The described method appears to be suitable for isolation of alpha-lactalbumin in a form adequate for milk formula engineering.