Modeling and identification of a nonlinear hybrid dynamical system in batch fermentation of glycerol

A nonlinear hybrid dynamical system is established to describe the batch culture of glycerol to 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae (K. pneumoniae), in which glycerol is assumed to pass the cell membrane by passive diffusion coupled with facilitated transport and transport mechanism of 1,3-PD is assumed to be uncertain. The existence, uniqueness and continuity of solutions are also discussed. To infer the most reasonable transport mechanism of 1,3-PD, a system identification model consisting of both discrete and continuous variables is proposed. Additionally, we construct a two-phase optimization algorithm on the basis of modified complex method together with very fast simulated annealing technology. Numerical results show that it is most reasonable for 1,3-PD to pass the cell membrane by passive diffusion coupled with facilitated transport and that the optimization algorithm is valid.