Identification of hybrid dynamical system in glycerol fermentation: Estimating the inhibition range of 3-HPA onto two key enzymes based on biological robustness

摘要

As an important intermediate substance in the process of producing 1,3-propanediol (1,3-PD) by bio-dissimilation of glycerol, the concentration of 3-hydroxypropionaldehyde (3-HPA) has inhibitory action on glycerol dehydratase (GDHt) and 1,3-propanediol oxidoreductase (PDOR). Considering the transmission of glycerol and 1,3-PD across cell membrane by both passive diffusion and active transmission as well as the inhibitory action of 3-HPA on the specific rate of growth, this paper aims to establish and discuss a nonlinear hybrid dynamical system model to ascertain the concentration range of 3-HPA where it does exhibit an inhibitory action on GDHt and PDOR. A quantitative definition of biological robustness is presented and an identification model is established based on biological robustness. An algorithm procedure is constructed to solve the identification problem. Numerical results show that only within a proper concentration range 3-HPA can have inhibitory action on the two enzymes mentioned above.