KINETICS OF TAXOL PRODUCTION, GROWTH, AND NUTRIENT-UPTAKE IN CELL-SUSPENSIONS OF TAXUS-CUSPIDATA

Cell culture of Taxus cuspidata may represent an alternative to extrac tion of bark as a source of taxol and related taxanes. Cell suspension s of a cell line of T. cuspidata were grown for 44 days in shake flask s containing B5C2 medium. Throughout the growth cycle, fresh and dry w eight accumulation, taxol yield on a dry weight basis, taxol accumulat ion in the medium, pH and pigmentation variation in the medium, as wel l as the uptake of sucrose, glucose, fructose, nitrate, and inorganic phosphate from the culture medium were examined. The results showed th at the growth was relatively slow (doubling times of 17 and 20 days fo r fresh and dry weight, respectively), and taxol accumulation in the c ells was non-growth related (higher in the stationary phase) and at re latively low levels (up to 4 mu g/g of the extracted dry weight). Taxo l concentration in the medium had-two peaks: one during the early (0.4 -mu g/mL) and another during the late (0.1-mu g/mL) parts of the growt h cycle. On a volumetric basis, the average total amount of taxol prod uced during the stationary phase (day 38) was 0.15 mu g/ mL, of which approximately 66% was in the medium and 34% was in the cells. Total ca rbohydrate uptake was closely associated with the increase in dry biom ass. Sucrose was apparently extracellularly hydrolyzed after the first 6 days of culture; glucose was used before fructose. Nitrate was assi milated throughout the growth cycle, but phosphate was absorbed within the first week of culture. The pH variation showed an initial drop fo llowed by a trend toward alkalinization for most of the growth period. Dark pigmentation in the medium increased progressively, particularly during the stationary phase. (C) 1994 John Wiley & Sons, Inc.