ISOLATION OF IMMUNOGLOBULINS FROM CHEESE WHEY USING ULTRAFILTRATION AND IMMOBILIZED METAL AFFINITY-CHROMATOGRAPHY

A method was developed to isolate immunoglobulins (Ig) from cheese whe y using ultrafiltration (UF) and immobilized metal affinity chromatogr aphy (IMAC). Cheddar cheese whey was concentrated up to 30 times using UF prior to applying to an IMAC column. A 50-ml IMAC column was loade d with 17.3 ml of 50 mm CuCl2 for 2/3 Cu saturation of the column bed volume. Using 20 times concentrated whey, 1240 mg of IgG could be isol ated with 52% purity using glycine in the eluting buffer. Glycine was found to be a better competing ligand in the eluting buffer than NH4Cl . Approximately 152 mg of lactoferrin and 90 mg of lactoperoxidase wer e isolated with the IgG. The concentration factor, IMAC matrix support , UF conditions and diafiltration did not affect the recovery or purit y of IgG obtained by IMAC. By using concentrated whey rather than unco ncentrated whey, an 80% reduction in time for IMAC could be achieved. IMAC was found to give higher recovery and purity of IgG from concentr ated whey than ion exchange chromatography. A method was also develope d to obtain IgG from raw skim milk using UF and IMAC.