Metabolic Engineering of <i>Pseudomonas chlororaphis</i> Qlu-1 for the Enhanced Production of Phenazine-1-carboxamide

Abstract

Phenazine-1-carboxylic acid (PCA), the primary active ingredient of Shenqinmycin, was awarded the China Pesticide Certificate in 2011 due to its excellent antibacterial action. Phenazine-1-carboxamide (PCN) is a derivative of PCA, which is modified by the <i>phzH</i> gene, and its anti-bacterial effect is better than that of PCA. At present, PCN can be produced via <i>Pseudomonas</i> fermentation using an opportunistic pathogen, <i>Pseudomonas aeruginosa</i>. Qlu-1 is an environmentally friendly strain of <i>Pseudomonas chlororaphis</i> that can produce phenazine derivatives. We replaced the <i>phzO</i> gene with the <i>phzH</i> gene from <i>P. aeruginosa</i> to achieve PCN accumulation. Different strategies were used to enhance PCN production: knocking out of negative regulatory factors, enhancing the shikimate pathway by gene overexpression and gene knocking, and using fed-batch fermentation. Finally, an engineered strain of <i>P. chlororaphis</i> was produced, which produced 11.45 g/L PCN. This achievement indicates that Qlu-1 could be modified as a potential microbial cell factory for PCN production by metabolic engineering.