Optimal design for continuous conversion of glycerol to 1,3-propanediol using a new feedback control law

Feedback control for the production of 1,3-propanediol by glycerol in microbial fermentation is considered. The feedback control law is assumed to be a linear function of the state vector, whose coefficients are differentiable functions of fermentation time. The selection of these coefficients should maximize the concentration of the target production. Thereby, the optimal control problem can be transformed into an optimal parameter selection problem, which is strongly nonlinear and may have multiple local optimal solutions. A novel adaptive particle swarm optimization embedded with Tabu Search is developed to solve this problem. The numerical results show that the proposed feedback control strategy significantly improves both the concentration and productivity of 1,3-propanediol and shortens the settling time in continuous culture. Additionally, the proposed numerical optimization method quickens the convergence rate and enhances the computational robustness.