ACTIVITY OF TYROSOL GLUCOSYLTRANSFERASE AND IMPROVED SALIDROSIDE PRODUCTION THROUGH BIOTRANSFORMATION OF TYROSOL IN RHODIOLA-SACHALINENSIS CELL-CULTURES

The activity of tyrosol glucosyltransferase (TGase) of Rhodiola sachal inensis cells was found to be the highest at the exponential growth ph ase while the intracellular tyrosol accumulated in large amounts at th e stationary growth phase. This non-synchronization of the TGase activ ity with the tyrosol accumulation was responsible for the low yield of salidroside obtained in cell suspension cultures. When 1 mmol l(-1) e xogenous tyrosol was added to the culture at day 8 and subsequently in cubated for 24 h, nearly 95% of the added tyrosol was transformed to s alidroside. The optimal concentration of exogenous tyrosol for the glu cosylation reaction was 3 mmol l(-1). Excess high concentration of tyr osol was toxic to cell growth and inhibited the biotransformation reac tion. By repeated addition of 3 mmol l(-1) tyrosol at 24 h intervals o ver 3 d, very high salidroside yield of 516 mu mol g(-1) (15.4% of dry weight) was obtained. (C) 1998 Elsevier Science B.V. All rights reser ved.