The Parameter Identification And Optimal Control Of Microbial Fed-batch Fermentation

The method of microbial fermentation is an important mode of production in producing 1,3-Propanediol(1,3-PD). Although the microbial fed-batch culture of glycerol into 1,3-PD is a vital production mode, the present research results of microbial fed-batch culture system which only think about the concentration of five kinds extracellular materials instead of metabolic mechanism, concentration of intracellular materials and important intermediate products. It is necessary to take intracellular materials into consideration in microbial fermentation. This paper includes the following aspects:1. Build a system of microbial fed-batch fermentation and identify parameters.On the basis of research situation of the microbial fermentation to produce 1,3-PD between domestic and international, according to the characteristics of microbial fed-batch fermentation, a dynamic system of microbial fed-batch fermentation, taking the concentration of intracellular glycerol, 3-HPA and 1,3-PD into consideration, is built under the active transport and passive diffusion of glycerol and active transport and passive diffusion of 1,3-PD. The existence and uniqueness and dependence on initial values of the solution are discussed about the mode at the same time. Take the sum of square error between experimental data and computational values as the performance index to build parameters identification model under the same strategy feeding glycerol in every phase. The identifiability of model is proved at the same time and an improved particle swarm optimization algorithm is used to solve this model at last.2. Discuss the effect of specific growth rate of cells on mode.In the process of microbial fed-batch fermentation to produce 1,3-PD, the errors of modes which adopt different specific growth rate of cells are compared and then discuss the effect of specific growth rate of cells on mode. Finally, make a choice about which kind specific growth rate of cells is more suitable according to the numerical results for the researchers who study on microbial fed-batch to produce 1,3-PD.3. Discuss the optimal control of microbial fed-batch fermentation.During the process of fed-batch culture, the velocity of feeding glycerol is an important optimization variable for the concentration of 1,3-PD at terminal time, so the velocity of feeding glycerol is taken as control variable and the maximum concentration of 1,3-PD is taken as the performance index at the final time to build optimal control model. An improved particle swarm optimization algorithm is used to solve this model. Numerical simulations show that the concentration of 1,3-PD increase 10.33% than experimental data at the final time in fed-batch fermentation process. This provides guidance to the actual industrial production of 1,3-PD.