Robustness Analysis And System Identification Of Nonlinear Dynamical System Based On The Three Possible Transportation Of 1,3-PD Across Cell Membrane

The batch and continuous fermentation of bio-dissimilation of glccerol to 1,3-propane-diol (1,3-PD) by Klebsiella pneumoniae(K.pneumoniae) are investigated in this paper. On the basis of 3-hydroxypropionaldehyde(3-HPA) have no inhibition effect to the spe-cific growth rate of microorganisms and the transport mechanism of glycerol across cell membrane is passive diffusion and active transport, we present dynamic models and the corresponding nonlinear hybrid dynamic systems in terms of the three possible transporta-tion of 1,3-PD across cell membrane, and the properties of systems are studied. On the basis of the quantitative definition of biological robustness, we establish a nonlinear hybrid dynamical system identification model. Finally, we construct a algorithm to solve the iden-tification model, and infer the transport mechanism of 1,3-PD by numerical computing.In addition, this work is supported by National Natural Science Foundation"Optimization theory and algorithm of nonsmooth dynamic system in a class of complex networks"(No. 10871033) and the National High Technology Research and Development Program(863 Program)"Biodiesel and 1,3-Propanediol Integrated Production" (No.2007AA02Z208). The research can be helpful for deeply understanding metabolism pathways of glycerol fermentation by K.pneumoniae. The main results in this dissertation may be summarized as follows:1. Basing on batch and continuous fermentation of bio-dissimilation of glycerol to 1.3-PD by K.pneumoniae, we propose the nonlinear hybrid dynamical systems on the basis of three transport mechanisms of 1,3-PD. In this dissertation, without considering the inhibitory effect of 3-HPA on the growth of biomass and assuming that the glyc-erol transported by active transport coupled with passive diffusion, we aim to infer the most reasonable one from three possible transport mechanisms of 1,3-PD across the cell membrane (active transport, passive diffusion or active transport coupled with passive diffusion), and develop the corresponding nonlinear hybrid dynamical system to describe batch and continuous fermentation of glycerol. It is proved that the solution to the system uniquely exists and is continuous with respect to parameters. We propose a quantitative definition of biological robustness, and establish an identification model containing dis-crete and continuous parameters. Finally, we prove the identifiability and existence of the optimal solution of the identification model. 2. A numerical computation algorithm is constructed to solve the nonlinear hybrid dynamical systems identification model. The model is numerically solved by randomly generating large number of sample points from the admissible set of parameters. Through numerical computation, we obtain the most reasonable transportation of 1.3-PD across cell membrane.