S. Medusa Cell Suspension Culture Flavonoid Synthesis Regulation And Bioreactor Enlarge Cultured

Lu Dongping (Botany) Directed by Professor Zhao De-XiuSaussurea medusa Maxim, family compositae, is a famous Chinese traditional drug, in which the flavonoids are its main bioactive components. At the basis of the previous work in our lab, I focused my work on the regulation of flavonoids biosyntheses in cell suspension culture of S. medusa and the scale-up culture of S. medusa cells.The effect of precursors on flavonoids biosynthesis in cell suspension cultures of S. medusa was studied. The results showed that both precursors could promote the flavonoids biosynthesis. The optimum time for precursor feeding (OTPF) is 6th.day during the cell culture. L-pheylalanine and NaAc had the most significant promoting effect on flavonoids formation at the concentration of 0.1 mmol/L, when they were combined to add, They had a more significant promoting effect than they were added respectively.The flavonoids biosynthesis in cell suspension cultures of S. medusa was stimulated by treating with two abiotic elicitors, Silver nitrate and Glutathione, The elicitation was dependent on the elicitor concentration and the addition time of the elicitors. When the two elicitors were combined to add, the maximum flavonoids was 1.72 times as that of the control, more productive than they were added respectively.The cell suspension culture of S. medusa in a 2 L aerated and agitated bioreactor. The effects of agitation speed, aeration and inoculum size on cell growth and flavonoids production were studied and it was found that cells had optimum growth and flavonoids production when cultivated at 75 r/min, 700-1000 L/min and an inoculum of 4.0~5.0 g DW/L. A high cellbiomass of 13.8 g/L and flavonoids production of 416 mg/L was achieved after 12 days of cultivation. Time course study revealed that flavonoids biosynthesis was growth-associated. The studies on aggregates size distribution in the bioreactor showed that the aggregates breakup might adversely affect cell growth and lead to significant reduction of cell biomass and flavonoids production.