Optimal temperature control for a structured model of plant cell culture

This article calculates optimal open-loop temperature trajectories that maximize the average rate of product synthesis of a plant cell culture. It uses a previously published five-state mathematical model which describes the growth and product synthesis of a batch plant cell suspension culture of Catharanthus roseus under temperature control. The optimal open-loop temperatures maximize the final product concentration for predefined fermentation periods. A single switch in temperature is shown by computer simulation to be near optimal, with a 22% increase in final product yield over that obtained at the optimal constant temperature. Examination of the achieved final product yield as a function of fermentation period allows this period also to be chosen optimally. This time is reduced from 16 days in the constant temperature case to 12 days in the switched temperature case.