Four UDP-glucosyltransfease (GTF) fractions were separated from the cultured cells of Eucalyptus perriniana, all of which exclusively produced beta-thujaplicin 2-O-beta-D-glucoside from beta-thujaplicin (hinokitiol) in the presence of UDP-glucose (UDPG) as the sole glucose donor. An effective enzymatic system for repeated production of the monoglucoside has been developed by using an enzyme fraction as a water-insoluble biocatalyst in an enzyme membrane reactor (slurry reactor) equipped with an ultrafiltration membrane. The GTF also catalyzed the regioselective glucosylation of salicyl alcohol to salicin and of various polyphenols to naturally occurring pigments such as sugar-containing flavonoids. This study is the first to observe GTF activity in the enzyme fractions from the cultured cells of E. perriniana, which specifically catalyze the UDPG-dependent monoglucosylation of aromatic compounds and flavonoids.