title: Enrichment and characterization of chlorinated organophosphate ester-degrading mixed bacterial cultures.
abstract: Chlorinated organophosphate ester (OPE)-degrading enrichment cultures were obtained using tris(2-chloroethyl) phosphate (TCEP) or tris(1,3-dichloro-2-propyl) phosphate (TDCPP) as the sole phosphorus source. In cultures with 46 environmental samples, significant TCEP and TDCPP degradation was observed in 10 and 3 cultures, respectively, and successive subcultivation markedly increased their degradation rates. 67E and 45D stable enrichment cultures obtained with TCEP and TDCPP, respectively, completely degraded 20 muM of the respective compounds within 6 h and also the other, although the degradation rate of TCEP by 45D was relatively slow. We confirmed chloride ion generation on degradation in both cases and the generation of 2-chloroethanol (2-CE) and 1,3-dichloro-2-propanol (1,3-DCP) as metabolites of TCEP and TDCPP, respectively. 67E and 45D also showed dehalogenation ability toward 2-CE and 1,3-DCP, respectively. Addition of inorganic phosphate did not significantly influence their ability to degrade the chlorinated OPEs but markedly increased their dehalogenation ability, which was maximum at 0.2 mM of inorganic phosphate and decreased at a higher concentration. Denaturing gradient gel electrophoresis analysis showed that dominant bacteria in 67E are related to Acidovorax spp. and Sphingomonas spp. and those in 45D are Acidovorax spp., Aquabacterium spp., and Sphingomonas spp. This analysis indicated the relationship of the Sphingomonas- and Acidovorax-related bacteria with the cleavage of the phosphoester bond and dehalogenation, respectively, in both cultures. This is the first report on bacterial enrichment cultures capable of degrading both TCEP and TDCPP.
authors.affiliation: Department of Environmental Systems Engineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan. shoutaka@vos.nagaokaut.ac.jp
authors.forename: Shouji
authors.initials: S
authors.lastname: Takahashi
authors.forename: Koji
authors.initials: K
authors.lastname: Kawashima
authors.forename: Manami
authors.initials: M
authors.lastname: Kawasaki
authors.forename: Jun
authors.initials: J
authors.lastname: Kamito
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Endo
authors.forename: Kumiko
authors.initials: K
authors.lastname: Akatsu
authors.forename: Sadatoshi
authors.initials: S
authors.lastname: Horino
authors.forename: Ryo-Hei
authors.initials: RH
authors.lastname: Yamada
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kera
mesh_terms: D001673:Biodegradation, Environmental; D049109:Cell Proliferation; D018920:Coculture Techniques / Q000379:methods*; D042621:Comamonadaceae / Q000166:cytology / Q000502:physiology*; D006843:Hydrocarbons, Chlorinated / Q000378:metabolism*; D007220:Industrial Waste / Q000517:prevention & control*; D010755:Organophosphates / Q000378:metabolism*; D012988:Soil Microbiology; D020578:Sphingomonas / Q000166:cytology / Q000502:physiology*
chemical_list: D006843:Hydrocarbons, Chlorinated; D007220:Industrial Waste; D010755:Organophosphates