Preparation of fucose-containing galacto-oligosaccharides using a commercial β-galactosidase from Bifidobacterium bifidum

Human milk fucose-containing oligosaccharides play a significant role in the development and function of the infant gastrointestinal tract. Fucosyltransferases catalyse the formation of these oligosaccharides. This work focuses on the preparation and characterisation of fucose-containing galacto-oligosaccharides using the commercial β-galactosidase Nurica. We optimised the reaction conditions to increase the yield of fucose-containing galacto-oligosaccharides. We detected a variety of structures containing fucose, ranging from disaccharides to hexasacharides. Fucose was located predominantly at the reducing end and, to a lesser extent, at the non-reducing end or within the chain. Like galactose, fucose was substituted mainly at the C3 position, although 1,2- and 1,4-linkages also occurred, albeit in a less pronounced manner. In addition, 1,2-, 1,3-, 1,4-, and 1,6- β -glycosidic linkages were identified between the galactose and glucose units, including internal units in tri- and tetrasaccharides.