The efficient enzymatic synthesis of N-acetyllactosamine in an organic co-solvent

In the presence of beta-galactosidase from Bifidobacterium bifidum, N-acetyllactosamine was synthesized in significantly enhanced yield compared with earlier routes. Different proportions of the (1-->4)- and (1-->6)-linked forms were obtained depending on the choice of enzyme and reaction conditions, viz. the nature of added organic co-solvent (20-80% of 2-ethoxy ethyl ether, trimethyl phosphate, or acetone). The beta-(1-->4)-linked disaccharide was the major product and the beta-(1-->6)-linked disaccharide was the minor product. With beta-galactosidases from P. multicolor, A. oryzae, B. longum the beta-(1-->6) linkage was exclusively synthesized. Procedures for optimising the yield of N-acetyllactosamine are discussed. An immobilized enzyme on a nylon powder column was used for the efficient recycling of enzyme and synthesizing the disaccharide.