Kinetics and stoichiometry of growth of plant cell cultures of Catharanthus roseus and Nicotiana tabacum in batch and continuous fermentors.

Plant cell suspension cultures of Catharanthus roseus and Nicotiana tabacum were grown in stirred tank bioreactors operated in batch and continuous mode. The stoichiometry of growth of both species in steady-state glucose limited chemostats was studied at a range of different dilution rates. A linear relation was applied to describe specific glucose uptake, oxygen consumption, and carbon dioxide production as a function of the growth rate. Specific respiration deviated greatly from the linear relation. An unstructured mathematical model, based on the observed stoichiometry in the glucose limited chemostats, was applied to describe the growth in batch culture. From a comparison between the observed growth pattern in batch fermentors and computer simulations it appeared that the stoichiometry of growth of the C. roseus culture was different under steady-state and dynamic conditions. It was concluded that a mathematical model for the growth of suspension culture plant cells in which the biomass is considered to be a single compound with an average chemical composition is of limited value because large changes in the composition of the biomass may occur.