Improved taxol yield in cell suspension culture of Taxus wallichiana (Himalayan yew)

Cell culture of Taxus wallichiana Zucc (= T. baccata ssp wallichiana Zucc. Pilg.) (Himalayan yew) has been established and taxol-producing cell lines selected by cell line cloning. Cell line NC110 derived from needle leaf of a 40-year-old tree growing in Darjeeling Himalayas produced 0.018 % taxol in B-5 basal medium supplemented with 2,4-D (2 mg/l), kinetin (0.5 mg/l), and casein hydrolysate (0.5 %). This cell line has been maintained for over 2 years. Significant enhancement in the level of taxol (0.05 %) was obtained in this cell line by supplementation of the basal medium with 5 mg/l of IAA-phenylalanine instead of 2,4-D without adversely affecting cell growth. IAA-glycine also enhanced taxol level (0.03 %) while IAA alone (1 - 10 mg/l) was ineffective in inducing taxol accumulation. Using three different cell lines with different taxol-producing capacities, it has been demonstrated that 2,4-D and IAA-phenylalanine when present alone favour growth and taxol production but when combined enhance biomass to a maximum (six-fold in NC110) without enhancing taxol accumulation, suggesting that a two-stage culture may be beneficial for optimising taxol accumulation in cell culture of T. wallichiana.