title: Isolation and characterization of bacterial strains that have high ability to degrade 1,4-dioxane as a sole carbon and energy source.
abstract: Four novel metabolic 1,4-dioxane degrading bacteria possessing high ability to degrade 1,4-dioxane (designated strains D1, D6, D11 and D17) were isolated from soil in the drainage area of a chemical factory. Strains D6, D11 and D17 were allocated to Gram-positive actinomycetes, similar to previously reported metabolic 1,4-dioxane degrading bacteria, whereas strain D1 was allocated to Gram-negative Afipia sp. The isolated strains could utilize a variety of carbon sources, including cyclic ethers, especially those with carbons at position 2 that were modified with methyl- or carbonyl-groups. The cell yields on 1,4-dioxane were relatively low (0.179-0.223 mg-protein (mg-1,4-dioxane)(-1)), which was likely due to requiring energy for C-O bond fission. The isolated strains showed 2.6-13 times higher specific 1,4-dioxane degradation rates (0.052-0.263 mg-1,4-dioxane (mg-protein)(-1) h(-1)) and 2.3-7.8 fold lower half saturation constants (20.6-69.8 mg L(-1)) than the most effective 1,4-dioxane degrading bacterium reported to date, Pseudonocardia dioxanivorans CB1190, suggesting high activity and affinity toward 1,4-dioxane degradation. Strains D1 and D6 possessed inducible 1,4-dioxane degrading enzymes, whereas strains D11 and D17 possessed constitutive ones. 1,4-Dioxane degradation (100 mg L(-1)) by Afipia sp. D1 was not affected by the co-existence of up to 3,000 mg L(-1) of ethylene glycol. The effects of initial pH, incubation temperature and NaCl concentration on 1,4-dioxane degradation by the four strains revealed that they could degrade 1,4-dioxane under a relatively wide range of conditions, suggesting that they have a certain adaptability and applicability for industrial wastewater treatment.
authors.affiliation: Division of Sustainable Energy and Environmental Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan. ksei@kitasato-u.ac.jp
authors.forename: Kazunari
authors.initials: K
authors.lastname: Sei
authors.forename: Keiko
authors.initials: K
authors.lastname: Miyagaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Kakinoki
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Fukugasako
authors.forename: Daisuke
authors.initials: D
authors.lastname: Inoue
authors.forename: Michihiko
authors.initials: M
authors.lastname: Ike
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development / Q000302:isolation & purification*; D001673:Biodegradation, Environmental / Q000187:drug effects; D002244:Carbon / Q000494:pharmacology*; D004146:Dioxanes / Q000378:metabolism*; D004734:Energy Metabolism / Q000187:drug effects*; D004988:Ethers, Cyclic / Q000378:metabolism; D019855:Ethylene Glycol / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007700:Kinetics; D010802:Phylogeny; D013696:Temperature
chemical_list: D004146:Dioxanes; D004988:Ethers, Cyclic; D002244:Carbon; D019855:Ethylene Glycol; C025223:1,4-dioxane