Purification of β‐Galactosidase by Ion Exchange Chromatography: Elution Optimization Using an Experimental Design

β‐Galactosidase is an enzyme industrially used to hydrolyze milk lactose, generating dairy products destined for people intolerant to this sugar. Its importance is due to its galactosiltransferase activity. The effects of elution pH and salt gradient volume were evaluated for purification of β‐galactosidase by ion exchange chromatography using an experimental design and response surface techniques. The best conditions for purification of β‐galactosidase were pH 5.5 with an elution volume of 62.8 mL, obtaining a yield of 85.5 % and a 12‐fold increase in the purification factor in a one‐step chromatography process. Purification of β‐galactosidase by application of a single stage of ion exchange and evaluation of the important process parameters using an experimental design provided good results in the recovery and purification factor that could subsequently be scaled up.