title: Mineralization of paraoxon and its use as a sole C and P source by a rationally designed catabolic pathway in Pseudomonas putida.
abstract: Organophosphate compounds, which are widely used as pesticides and chemical warfare agents, are cholinesterase inhibitors. These synthetic compounds are resistant to natural degradation and threaten the environment. We constructed a strain of Pseudomonas putida that can efficiently degrade a model organophosphate, paraoxon, and use it as a carbon, energy, and phosphorus source. This strain was engineered with the pnp operon from Pseudomonas sp. strain ENV2030, which encodes enzymes that transform p-nitrophenol into beta-ketoadipate, and with a synthetic operon encoding an organophosphate hydrolase (encoded by opd) from Flavobacterium sp. strain ATCC 27551, a phosphodiesterase (encoded by pde) from Delftia acidovorans, and an alkaline phosphatase (encoded by phoA) from Pseudomonas aeruginosa HN854 under control of a constitutive promoter. The engineered strain can efficiently mineralize up to 1 mM (275 mg/liter) paraoxon within 48 h, using paraoxon as the sole carbon and phosphorus source and an inoculum optical density at 600 nm of 0.03. Because the organism can utilize paraoxon as a sole carbon, energy, and phosphorus source and because one of the intermediates in the pathway (p-nitrophenol) is toxic at high concentrations, there is no need for selection pressure to maintain the heterologous pathway.
authors.affiliation: Graduate Group in Microbiology, University of California, Berkeley, CA 94720-3224, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: de la Peña Mattozzi
authors.forename: Sundiep K
authors.initials: SK
authors.lastname: Tehara
authors.forename: Thomas
authors.initials: T
authors.lastname: Hong
authors.forename: Jay D
authors.initials: JD
authors.lastname: Keasling
mesh_terms: D001673:Biodegradation, Environmental; D007306:Insecticides; D008903:Minerals / Q000378:metabolism; D010261:Paraoxon / Q000378:metabolism*; D010278:Parathion / Q000378:metabolism; D016958:Pseudomonas putida / Q000378:metabolism*
chemical_list: D007306:Insecticides; D008903:Minerals; D010278:Parathion; D010261:Paraoxon