A cell suspension culture of Taxus media was established from a stable callus line of this species. The growth rate and production of paclitaxel and baccatin III of this cell suspension were significantly increased during the shake flask culture in its respective optimum media for cell growth and product formation, which were selected after assaying 24 different culture media. The highest yields of paclitaxel (2.09 mg L(-1)) and baccatin III (2.56 mg L(-1)) in the production medium rose (factors of 7.0 and 3.0, respectively) in the presence of methyljasmonate (220 microg g(-1) FW). When the elicitor was added together with mevalonate (0.38 mM) and N-benzoylglycine (0.2 mM), the increase in the yields of paclitaxel and baccatin III was even higher (factors of 8.3 and 4.0, respectively). Thereafter, a two-stage culture for cell suspension was carried out using a 5-l stirred bioreactor running for 36 days, the first stage being in the cell growth medium until cells entered their stationary growth phase (12 days) and the second stage being in the production medium supplemented with the elicitor and two putative precursors in the concentrations indicated above. Under these conditions, 21.12 mg L(-1) of paclitaxel and 56.03 mg L(-1) of baccatin III were obtained after 8 days of culture in the production medium.

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A cell suspension culture of Taxus wallichiana (Himalayan Yew) was grown in shake flasks and a 20-L airlift bioreactor running for 28 days in a batch mode, and its capacity to accumulate paclitaxel and baccatin III was measured. When both culture types were in the highest productive state (from day 24 to day 28), there was a greater accumulation of paclitaxel and baccatin III in the bioreactor culture than in the shake flask culture (factor of 2.0 and 1.2, respectively). These increases in paclitaxel and baccatin III production cannot be related to the difference observed between the growth rates of both cultures, because when the bioreactor culture was at maximum productivity, its cell biomass, expressed in g L(-1) of dry weight, was similar to that obtained in the shake flask culture. It seems that these improvements were mainly due to adequate aeration and mixing of the culture in the bioreactor. The maximum yield observed for paclitaxel (20.84 mg x L(-1) day 24) and baccatin III (25.67 mg x L(-1) day 28) represents a productivity of 0.90 mg x L(-1) d(-1) and 0.93 mg x L(-1) x d(-1) respectively.