Multi-enzymatic Glucosylation Using Eucalyptus UDP-Glucosyltransferase Coupled UDPglucose-Fermentation by Bakers’ Yeast

Abstract

  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. al., J. Ferment. Bioeng., 84 (5), pp. 455-460, 1997) has been effectively done by coupling UDPglucose-fermentation by bakers’ yeast. For example, β-thujaplicin (hinokitiol) and p-aminobenzoic acid were converted respectively to their corresponding β-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 substrate of β-glucosidase, or DL-1,2-anhydro-myo-inositol, an inhibitor for the enzyme in the reaction mixture, could increased the yield of these β-D-monoglucosides. This new enzymatic system could also be used for the synthesis of flavonoid glucosides such as isoquercitrin (quercetin 3-O-β-D-glucoside).