title: Identification of alkaline phosphatase genes for utilizing a flame retardant, tris(2-chloroethyl) phosphate, in Sphingobium sp. strain TCM1.
abstract: Tris(2-chloroethyl) phosphate (TCEP) is a haloalkyl phosphate flame retardant and plasticizer that has been recognized as a global environmental contaminant. Sphingobium sp. strain TCM1 can utilize TCEP as a phosphorus source. To identify the phosphomonoesterase involved in TCEP utilization, we identified four putative alkaline phosphatase (APase) genes, named SbphoA, SbphoD1, SbphoD2, and SbphoX-II, in the genome sequence. Following expression of these genes in Escherichia coli, APase activity was confirmed for the SbphoA and SbphoX-II gene products but was not clearly observed for the SbphoD1 and SbphoD2 gene products, owing to their accumulation in inclusion bodies. The single deletion of either SbphoA or SbphoX-II retarded the growth and reduced the APase activity of strain TCM1 cells on medium containing TCEP as the sole phosphorus source; these changes were more marked in cells with the SbphoX-II gene deletion. In contrast, the deletion of either SbphoD1 or SbphoD2 had no effect on cell growth or APase activity. The double deletion of SbphoA and SbphoX-II resulted in the complete loss of cell growth on TCEP. These results show that SbPhoA and SbPhoX-II are involved in the utilization of TCEP as a phosphorus source and that SbPhoX-II is the major phosphomonoesterase involved in TCEP utilization.
authors.affiliation: Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan. shoutaka@vos.nagaokaut.ac.jp.
authors.forename: Shouji
authors.identifier: http://orcid.org/0000-0002-0279-9173
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Katanuma
authors.affiliation: Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan.
authors.forename: Katsumasa
authors.initials: K
authors.lastname: Abe
authors.affiliation: Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kera
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics* / Q000378:metabolism; D001673:Biodegradation, Environmental; D049109:Cell Proliferation / Q000235:genetics; D005411:Flame Retardants / Q000378:metabolism*; D017353:Gene Deletion; D010755:Organophosphates / Q000737:chemistry / Q000378:metabolism*; D010968:Plasticizers / Q000378:metabolism*; D042301:Sphingomonadaceae / Q000235:genetics* / Q000378:metabolism
chemical_list: D005411:Flame Retardants; D010755:Organophosphates; D010968:Plasticizers; C031324:tris(chloroethyl)phosphate; D000469:Alkaline Phosphatase
keywords: Alkaline phosphatase; E. coli expression; Gene disruption; Sphingobium sp. strain TCM1; Tris(2-chloroethyl) phosphate