Biochem. Eng. J.

Cell culture of Saussurea medusa in a 2-1 periodically submerged air-lift bioreactor (PSAB) was investigated. The periodically unsubmerged (immobilization culture) and submerged (suspension culture) operation of the whole bioreactor system was controlled by the electromagnetic valves and driven rod controller connected with the time controller. The maximum cell biomass (10.4 gl(-1)), content of total flavonoids (4.8%), production of total flavonoids (501 mgl(-1)) and the optimal size distribution of cell aggregates were obtained under the optimal unsubmerged/submerged period of 10 min/8 h (the cell inoculation size was 1.0 gl(-1), and the air flowrate was 20/401 h(-1)). Though the content of total flavonoids was still a little lower than that obtained from the shake flask culture, the specific growth rate of cells in PSAB was 2.1-fold and the production of total flavonoids was 1.7-fold of those in shake flasks. It was concluded that PSAB had advantages in improving cell growth of S. medusa and the production of total flavonoids. (C) 2004 Elsevier B.V. All rights reserved.Cell culture of Saussurea medusa in a 2-1 periodically submerged air-lift bioreactor (PSAB) was investigated. The periodically unsubmerged (immobilization culture) and submerged (suspension culture) operation of the whole bioreactor system was controlled by the electromagnetic valves and driven rod controller connected with the time controller. The maximum cell biomass (10.4 gl(-1)), content of total flavonoids (4.8%), production of total flavonoids (501 mgl(-1)) and the optimal size distribution of cell aggregates were obtained under the optimal unsubmerged/submerged period of 10 min/8 h (the cell inoculation size was 1.0 gl(-1), and the air flowrate was 20/401 h(-1)). Though the content of total flavonoids was still a little lower than that obtained from the shake flask culture, the specific growth rate of cells in PSAB was 2.1-fold and the production of total flavonoids was 1.7-fold of those in shake flasks. It was concluded that PSAB had advantages in improving cell growth of S. medusa and the production of total flavonoids. (C) 2004 Elsevier B.V. All rights reserved