Enzymatic-catalyzed synthesis of alkylglycosides in monophasic and biphasic systems. I. The transglycosylation reaction

Enzymatic synthesis of butylgalactoside via the transglycosylation reaction of lactose was carried out using P-galactosidase from Aspergillus oryzae. Reactions were performed in monophasic (butanol phase) and biphasic systems (emulsified aqueous in butanol phase). The results indicated that water co ntent was an essential parameter of this reaction. In the case of the monop hasic system, addition of water led to a significant increase of product co ncentration. The highest concentration was obtained at 17% (v/v) of water. Conversely, in the case of the biphasic system, increasing the aqueous/buta nol phase ratio (v/v) provoked epsilon. decrease of the final butylgalactos ide concentration. In this system, the reaction performance was lower than that in the monophasic system. Lactose favorably influenced the reaction sy nthesis. However, at high concentrations, it led to a drastic decrease of t he product concentration. (C) 1999 Elsevier Science B.V. All rights reserve d.