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

The extraction of high-value dairy proteins such as lactoferrin and lactoperoxidase normally requires extensive pre-treatments of milk to remove fat and caseins by centrifugation, precipitation, Ca2+ chelation and/or filtration. Similarly, fat and caseins are normally removed prior to capture of recombinant proteins from the milk of transgenic animals. Such pre-treatments can result in significant loss of protein yield and/or activity. In this paper, we demonstrate that it is possible to pass significant quantities of raw, untreated milk through a 5 cm high XK16 chromatography column (volume 10 mL) packed with SP Sepharose Big Beads™ (GE Healthcare, Uppsala, Sweden) without exceeding the maximum allowable backpressure, provided that the processing temperature is kept nominally around milking temperature (35–37 °C). Results show that more than 100 column volumes of raw milk could be loaded at 300 cm/h before breakthrough of lactoperoxidase occurred. The dynamic capacity for adsorbing lactoferrin and lactoperoxidase simultaneously under these conditions was approximately 48.6 mg/mL of packed resin. Minor leakage (4.6% of the feed concentration) of lactoferrin occurred throughout the loading process but major breakthrough occurred only after approximately 100 column volumes were loaded.