Microbial production, immobilization and applications of β-D-galactosidase

beta-D-Galactosidase (beta-D-galactoside galactohydrolase, E.C. 3.2.1.23), most commonly known as lactase, is one of the most important enzymes used in food processing, which catalyses the hydrolysis of lactose to its constituent monosaccharides, glucose and galactose. The enzyme has been isolated and purified from a wide range of microorganisms but most commonly used beta-D-galactosidases are derived from yeasts and fungal sources. The major difference between yeast and fungal enzyme is the optimum pH for lactose hydrolysis. The application of P-D-galactosidase for lactose hydrolysis in milk and whey offers nutritional, technological and environmental applications to human life. In this review, the main emphasis has been given to elaborate the various techniques used in recent times for the production, purification, immobilization and applications of P-D-galactosidase. (c) 2006 Society of Chemical Industry.