Optimal feed rate profiles for fed-batch culture in penicillin production

Skolpap, W., Scharer, J.M., Douglas, P.L. and Moo-Young, M. Optimal feed rate profiles for fed-batch culture in penicillin production Songklanakarin J. Sci. Technol., 2005, 27(5) : 1057-1064 The fed-batch optimization of penicillin productivity was applied as an example of optimization algorithm verification. The objective function of this problem was to optimize penicillin productivity by determination of feed rate trajectory. This study compared the optimized results derived from the proposed algorithm and from the iterative dynamic programming. Three decision variables for the proposed algorithm comprised t s (switching time from exponential to linear feeding schedules), K (constant in feed rate equation), and e e e e e (a multiplier on substrate requirement). Estimation of this set of decision variables employed Markov chain Monte Carlo procedures (the Gibbs parameter sampling and the Metropolis-Hasting algorithm) using an originally given set of initial values. The optimization procedure was divided into two time periods as follows: i) the time period of exponential feeding policy, t t s . The calculation procedure of the first period of fermentation time had been proposed by integrating Pontryagin’s optimum principle and Luedeking-Piret equation. The feed rate profile during the later period was obtained from the direct substitution of desired substrate requirement derived from Monod equation. The optimal feed-rate profile corresponded to the values of decision variables as follows [t s K e] = [35.937 ORIGINAL ARTICLE