A kinetic model for phenazine-1-carboxylic acid production by pseudomonas sp. M18G

The development of optimal bacterial strains for industrial scale of fermentation would benefit from a quantitative model of rate of gene expression from DNA to RNA, from DNA to protein, and ultimately from DNA to the metabolites. In this study, we developed such a model for phenazine-1-carboxylic acid (PCA) biosynthesis in Pseudomonas sp. strain M18G. The PCA biosynthesis is controlled by anoperon phzABCDEFG. Two variables were modeled during fermentation: the rate of phzCmRNA synthesis and the rate of PCA production. A kinetic model was established based on Logistic and Luedeking-Piret equations. Our data demonstrated that the kinetic model provides a good description of temporal variations of biomass, product and mRNA levels in PCA fermentation process. Based on estimated kinetic parameters, this model was used to improve the PCA production in Pseudomonas sp. strain M18G, and monitor the level of phzC mRNA, which act as a reference index in optimization of engineering bacteria. In addition, the model can be applied for monitoring internal state of cells in the process of large scales fermentation.