A dynamic model for a continuous extractive fermentation process is proposed. Using this model and the Iterative Dynamic Programming algorithm, optimal operating profiles are identified for process start-up from conventional fermentation operation. Under the optimal operating profile, profit during the transient operation accumulates at a rate approaching that of steady state operation. A sensitivity analysis investigating the effect of economic variations on the overall profit function shows that optimization of manipulated variable profiles primarily reduces the impact of substrate cost, so that the profit function approaches a linear function of the product value.