Abstract
Background: Trans-2,3-dihydro-3-hydroxyanthranilic acid (DHHA) is a cyclic β-amino acid used for the synthesis of non-natural peptides and chiral materials. It is an intermediate product of phenazine production in Pseudomonas spp . Lzh-T5 is a P. chlororaphis strain isolated from tomato rhizosphere found in China. It can synthesize three antifungal phenazine compounds. Results: Disrupting the phzF gene of P. chlororaphis Lzh-T5 results in DHHA accumulation. Several strategies were used to improve production of DHHA: enhancing the shikimate pathway by overexpression, knocking out negative regulatory genes, and adding metal ions to the medium. In this study, three regulatory genes ( psrA , pykF, and rpeA ) were-disrupted in the genome of P. chlororaphis Lzh-T5, yielding 4.55 g/L of DHHA. When six key genes selected from the shikimate, pentose phosphate, and gluconeogenesis pathways were overexpressed, the yield of DHHA increased to 6.89g/L. Fe 3+ was added to the medium for DHHA fermentation. This genetically engineered strain increased the DHHA production to 10.45g/L. Conclusions: P. chlororaphis Lzh-T5 could be modified as a microbial factory to produce DHHA by inactivating phzF , disrupting negative regulatory genes, overexpressing key genes, and adding metal ions to medium for fermentation.
Role of the phenazine-inducing protein Pip in stress resistance of Pseudomonas chlororaphis
