The negligible role of carbon dioxide and ethylene in ajmalicine production by Catharanthus roseus cell suspensions

Summary Removal of gaseous metabolites in an aerated fermenter affects ajmalicine production by Catharanthus roseus negatively. Therefore, the role of CO₂ and ethylene in ajmalicine production by C. roseus was investigated in 3 l fermenters (working volume 1.8 l) with recirculation of a large part of the exhaust air. Removal of CO₂, ethylene or both from the recirculation stream did not have an effect on ajmalicine production. Inhibition of ethylene biosynthesis in shake flasks with Co²⁺, Ni²⁺ or aminooxyacetic acid did not affect ajmalicine production. However, the removal of CO₂ did enhance the amount of extracellular ajmalicine.