Enzymatic synthesis of oligosaccharides and alkylglycosides in water-organic media via transglycosylation of lactose

Abstract

The synthesis of oligosaccharides and alkylglycosides via transglycosylation reaction of lactose by Aspergillus oryzae β-glycosidase was studied in the presence of water miscible organic solvents—DMSO (N', N'-dimethylsulfoxid) and DMF (N', N'- dimethylformamide) and water immiscible hydrophilic alcohols—isopropanol (2-propanol), secondary butanol (2-butanol) and isobutanol (2-metyl-l-propanol). In the presence of DMSO and DMF, both the transglycosylation and hydrolytic activities of the enzyme were suppressed. The yield of trisaccharides after 24h incubation was about 5% in the presence of 20% DMSO or 20% DMF. In a medium containing secondary butanol no transglycosylation products were detected. When isopropanol (20%) was used, trisaccharides (3.54%) and isopropylgalacosides (7.52%) were obtained after 24h incubation. The highest transglycosylation activity of Aspergillus oryzae β-glycosidase was demonstrated in the presence of isobutanol. Increase in isobutanol concentration (up to 50%) enhanced the amount of transglycosylation products and a maximum yield of 6.68% trisaccharides and 14.5% isobutylgalactosides was reached. © 2006 Taylor and Francis Group, LLC.