Abstract:

Effects of the basic media and inoculum size on birch cell growth and the triterpenoid production were investigated using birch suspension cells, on this basis, the kinetic relationships of birch cell growth, triterpenoid production and nutrient consumption were also analyzed. The results showed the opbimal conditions for the birch cell growth and triterpenoid production were 20~30 g ·L^-1(FW)of inoculum size, in B5 medium. The kinetics analysis for birch cell suspension culture showed that triterpenoid production was increasing with the birch cell growth during a cell subculture cycle. During the teriod, the maximum specific growth rate was 0.18 on the 12^th day, and the maximum triterpenoid synthesis rate was 0.73 mg · g^-1 on the 9^th day. Sugar, NO^-₃, NH⁺₄ and PO^3-₄ in the culture medium were nearly used up on the 9^th day, The content of sugar, NO^-₃, and PO^3-₄ in birch cell were highest on 6^th day, but the content of NH⁺₄ in birch cell were higher on 3^th day. The results snggested that the nutrient deficiencies in medium wonld limited the cell rapid multiplication and triterpenoid content accumulation.

Key words: Betula platyphylla, suspension cell, triterpenoid, nutrient