Harmonic multi-objective differential evolution approach for multi-objective optimization of fed-batch bioreactor

Lysine as one of the essential amino acids is often used as a chemical agent, medicament, food material, and human and animals feed additive. Microbial fermentation is one of the most economical processes to produce lysine. Batch or fed-batch fermentation processes are often used to produce lysine. The use of fed-batch operation improves the productivity, reduces the fermentation time, and increases the yield of the reaction. Using a mathematical modeling approach, it is possible to obtain a deeper insight of biochemical-based processes. In this manuscript, an optimal feeding profile for fed-batch bioreactor is obtained for the multi-objective optimization (MOO) of conflicting objectives, i.e., the yield (with two different expressions) and the productivity. MODE-III and Harmonic MODE algorithms are used for the MOO study. Pareto optimal fronts are also reported for constant feeding rate, singular feeding rates, and for the different feeding rates in a given range. With the increase in the value of the feed rate, the productivity increases while the yield decreases. Both versions of the MODE algorithm result in the smooth Pareto front; however, the Harmonic MODE algorithm results in a good and diverse set of solutions.