Screening of fungal sources of -galactosidase with potential for the synthesis of prebiotics

Abstract

[Excerpt] β-Galactosidases (EC 3.2.1.23), also known as lactases, are a family of enzymes able to catalyse two different types of reactions, namely hydrolysis and transgalactosylation. The hydrolytic activity is commonly applied in the food industries to reduce the lactose content of dairy products, preventing lactose crystallization problems and increasing sweetness, flavour and solubility. On the other hand, transgalactosylation reactions have been explored in the synthesis of lactose-based prebiotics, such as galacto-oligosaccharides (GOS), lactosucrose [1] and lactulose [2], with potential application in the pharmaceutical and food industry. These prebiotics are enzymatically produced through the hydrolysis of lactose and further transfer of a galactosyl residue to a suitable acceptor, i.e. fructose for the disaccharide lactulose; sucrose for the trisaccharide lactosucrose; and lactose for GOS. The sources of βgalactosidase are extensively distributed in nature, namely in microorganisms, plants and animal organs. [...]