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

A method was developed to isolate immunoglobulins (Ig) from cheese whey using ultrafiltration (UF) and immobilized metal affinity chromatography (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 loaded 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 isolated 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 were isolated with the IgG. The concentration factor, IMAC matrix support, UF conditions and diafiltration did not affect the recovery or purity of IgG obtained by IMAC. By using concentrated whey rather than unconcentrated whey, an 80% reduction in time for IMAC could be achieved. IMAC was found to give higher recovery and purity of IgG from concentrated whey than ion exchange chromatography. A method was also developed to obtain IgG from raw skim milk using UF and IMAC.