Heuristic Feed Rate Profiles for Optimal Yield and Productivity of Fed-Batch Bioprocesses

Abstract The optimization of two important classes of fed-batch fermentation processes with respect to the limiting substrate feed rate is considered: (i) growth of one biomass, and (ii) growth and product formation. Two different performance criteria are compared: yield and productivity. Heuristic feed rate profiles are derived based on (i) the optimal control solution according to the minimum principle, and (ii) the qualitative behavior of the specific rates for growth and possibly product formation. For biomass production processes, the heuristic strategy coincides exactly with the optimal control solution and is independent of the performance index considered. For product formation processes, the same heuristic approach can be used to optimize both yield and productivity in spite of the well known conflict between them.