Influence of the combination of nutrient feed with dissolved oxygen control on taxol production in suspension cultures of Taxus chinensis (Pilg.) Rehd. was investigated in bioreactors. Addition of feeding medium with 20 g/L sucrose on day 16 enhanced both the biomass and taxol production in 5-L bioreactors. Further investigation of the fed-batch cultures in a 20-L bioreactor showed that cultivation under a low dissolved oxygen tension (DOT) of 20% for the entire culture resulted in the highest taxol content of 0.98 mg/g DW, while the taxol production was lower than that with 40% and 60% DOT. Moreover, taxol accumulation was remarkably improved by the cultivation of cells initially under DOT of 60% for 20 d followed by changing the DOT to 20% for another 12 d. By combining the use of these two strategies, a maximum taxol content of 18.7 mg/L was obtained in a 20-L bioreactor.
The effect of dissolved oxygen controlled level on the taxol production by suspended cell culture of Taxus chinensis was examined in shake flasks and in a 20L aerated and agitated bioreactor with a six\|flat\|bladed turbine.It was found in shake flasks that oxygen supply exhibited significant influence on the production of taxol.Further investigation in bioreactor showed that noly 1.5mg/L taxol was produced when DO(dissolved oxygen)level was 20%.Taxol production increased when DO level was increased to 40%～60%.Moreover,taxol accumulation was remarkably improved by the cultivation of cells initially at the DO level of 60% during the growth phase for 14 days followed by changing the DO level to 20%～40% during the taxol production phase for another 10 days.An optimum taxol level of 7.2mg/L was obtained by the dissolved oxygen controlled process.
