Reactive oxygen species, cell growth, and taxol production of Taxus cuspidata cells immobilized on polyurethane foam

Dynamic changes in reactive oxygen species (ROS) of Taxus cuspidata cells immobilized on polyurethane foam were investigated and the relation between ROS content and taxol production was discussed. Immobilization shortened the lag period of cell growth and moderately increased H₂O₂ and O₂ ^−• contents inside the microenvironment within the first 15 d. After 20 d, excessive production of H₂O₂ and O₂ ^−• was observed accompanied by marked increases in membrane lipid peroxidation and cell membrane permeability. The taxol content of immobilized cells was fourfold that of suspended cells at d 35. The addition of exogenous H₂O₂ barely affected malondialdehyde content and cell membrane permeability but led to an obvious accumulation of taxol. It is inferred that the intracellular and extracellular H₂O₂ inside the microenvironment might be one factor promoting taxol biosynthesis under the immobilization stress.