Reconstruction and analysis of a three-compartment genome-scale metabolic model for Pseudomonas fluorescens

With the versatile metabolic diversity, Pseudomonas fluorescens is a potential candidate in petroleum aromatic hydrocarbon (PAH) bioremediation. Genome-scale metabolic model (GSMM) can provide systematic information to guide the development of metabolic engineering strategy to improve microbial activity. In this study, a GSMM for P. fluorescens SBW25 was reconstructed, which is termed as lCW1057. The reconstruction was based on automatic reannotation and manual curation. The periplasmic compartment was constructed to better represent the proton gradient profile. The reconstructed proton transport chain has a P/O (ATP generated per atom oxygen consumed by the respiratory chain) ratio of 11/8. Flux balance analysis (FBA) was performed to explore the whole-cell metabolic flow. The model suggested that instead of Embden-Meyerhof-Parnas pathway, Entner-Doudoroff pathway was used in glycolytic metabolism of P. fluorescens, indicating that the growth of P. fluorescens is more energy dependent. Furthermore, P. fluorescens can use nitrate as the terminal electron acceptor for the glucose metabolism. The β-ketoadipate pathway was involved in catechol metabolism. The uptake of oxygen is mandatory for the aromatic ring cleavage. The in silico and in vitro maximum specific growth rate was compared, resulting in 10% difference when catechol was used as the sole carbon source.