Multi-enzymatic glucosylation using Eucalyptus UDP-glucosyltransferase coupled UDPglucose-fermentation by bakers' yeast

The enzymatic synthesis of glucoside compounds using a membrane-associated UDP-glucosyltransferase fraction from Eucalyptus perriniana cultured cells as a water-insoluble catalyst (N. Nakajima, et. at., J. Ferment. Bioeng., 8 4 (5), pp. 455-460, 1997) has been effectively done by coupling UDPglucose- fermentation by bakers' yeast. For example, beta-thujaplicin (hinokitiol) a nd p-aminobenzoic acid were converted respectively to their corresponding b eta-D-monoglucosides with the conversion rate of around 24-26% by the multi -enzymatic system with UDPglucose as a glucose donor, which is produced by yeast cells from glucose and 5'-UMP. Addition of either cellobiose, a subst rate of beta-glucosidase, or DL-1,2-anhydro-myo-inositol, an inhibitor for the enzyme in the reaction mixture, could increased the yield of these beta -D-monoglucosides. This new enzymatic system could also be used for the syn thesis of flavonoid glucosides such as isoquercitrin (quercetin 3-O-beta-D- glucoside).