title: Relation between dissolved oxygen concentration and ajmalicine production rate in high-density cultures of Catharanthus roseus.
abstract: The relation between dissolved oxygen (DO) and the ajmalicine production rate of Catharanthus roseus was investigated in 15-L tank reactors at constant stirrer speed and gas flow rate. Below a DO concentration of 29% of air saturation the ajmalicine production rate was less than 0.06 micromol/g/d. Above a DO of 43% the ajmalicine production rate was constant at 0.21 micromol/g/d. Between a DO of 29% and 43% there was a strong relation between the ajmalicine production rate and the DO concentration. After a period of at least 12 days at DO <or=29% the culture lacked the ability to adapt to a DO >or=57%. A kinetic equation is proposed for the relation between DO and the specific ajmalicine production rate.
authors.affiliation: Biotechnological Sciences Delft Leiden, Sector Industrial Plant Biotechnology, Department of Biochemical Engineering, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
authors.forename: J E
authors.initials: JE
authors.lastname: Schlatmann
authors.forename: J L
authors.initials: JL
authors.lastname: Vinke
authors.forename: H J
authors.initials: HJ
authors.lastname: Ten Hoopen
authors.forename: J J
authors.initials: JJ
authors.lastname: Heijnen