Effects of medium nutrition on cell growth and isocamptothecin A and B production by suspension cell culture of Camptotheca acuminata

The effects of initial sucrose concentration, nitrate to ammonium ratio, total N concentration and phosphate concentration in medium on cell growth and isocamptothecin A and B synthesis by suspension cell culture of Camptotheca acuminata were investigated in 250 mL shake flasks. 30 g L-1 sucrose concentration was beneficial to secondary metabolites synthesis. The cell growth and metabolites synthesis were also affected by the ratio of NO-3/NH 4, and nitrate was favourable for cell growth. The maximum dry weight was achieved when nitrate was used as the sole N source. The effect of total initial N on the cell cultures was also investigated with NO-3/NH 4 ratio of 1∶2. The final dry cell weight was similar throughout culture period and 50 mM initial N was favourable for secondary metabolite synthesis. 50 mM initial phosphate concentration facilitated both cell growth and secondary metabolites synthesis.