ENZYMATIC-SYNTHESIS OF ALKYL-ALPHA-GLUCOSIDE CATALYZED BY A THERMOSTABLE ALPHA-TRANSGLUCOSIDASE IN SOLVENT-FREE ORGANIC MEDIUM

alpha-Transglucosidase from Talaromyces duponti was used to synthesize different alkyl-alpha-D-glucosides from alpha(1-4) linked carbohydrat e donors. The enzymatic preparation, purified by a single step, consis ting of hydrophobic interaction chromatography, was sufficiently pure for very stereospecific synthesis to be achieved. Biphasic and homogen eous organic media could be compared for such purposes. Yields appeare d to be two- to threefold higher in low-water biphasic media. High con centrations of the glucosyl donor were present in the aqueous phase, w hile water-immiscible alcohols were used as glucosyl accepters. The hi gh efficiency of the method was attributed to the shift of the thermod ynamic equilibrium thanks to the extraction of the product from the aq ueous phase, where the reaction occurs, into the organic phase. Operat ed in a continuous biphasic reactor, T. duponti alpha-transglucosidase showed a good thermostability with a half-life of 23 days at 30 degre es C.