3-galactosidase is an important enzyme for food industry, and since it is an intracellular enzyme, the cells must be treated with chemical and physical agents to increase permeability prior to immobilization 13Galactosidase was entrapped into calcium alginate for hydrolysis of lactose from milk and whey in batch process and as well as in continuous packed bed columns. Entrapped cross-linked concanavalin A-(3-galactosidase complex offered high stability against physical and chemical denaturants. Retention of immobilized enzyme was found to be more efficient and this immobilization system could be employed efficiently in a reactor for the continuous conversion of lactose in the presence of milk and whey for food industry