title: Adaptation of Pseudomonas sp. strain 7-6 to quaternary ammonium compounds and their degradation via dual pathways.
abstract: Pseudomonas sp. strain 7-6, isolated from active sludge obtained from a wastewater facility, utilized a quaternary ammonium surfactant, n-dodecyltrimethylammonium chloride (DTAC), as its sole carbon, nitrogen, and energy source. When initially grown in the presence of 10 mM DTAC medium, the isolate was unable to degrade DTAC. The strain was cultivated in gradually increasing concentrations of the surfactant until continuous exposure led to high tolerance and biodegradation of the compound. Based on the identification of five metabolites by gas chromatography-mass spectrometry analysis, two possible pathways for DTAC metabolism were proposed. In pathway 1, DTAC is converted to lauric acid via n-dodecanal with the release of trimethylamine; in pathway 2, DTAC is converted to lauric acid via n-dodecyldimethylamine and then n-dodecanal with the release of dimethylamine. Among the identified metabolites, the strain precultivated on DTAC medium could utilize n-dodecanal and lauric acid as sole carbon sources and trimethylamine and dimethylamine as sole nitrogen sources, but it could not efficiently utilize n-dodecyldimethylamine. These results indicated pathway 1 is the main pathway for the degradation of DTAC.
authors.affiliation: Department of Biofunctional Chemistry, Faculty of Agriculture, Kobe University, Rokko, Nada-ku, Kobe, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Takenaka
authors.forename: Takashi
authors.initials: T
authors.lastname: Tonoki
authors.forename: Kazuya
authors.initials: K
authors.lastname: Taira
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Murakami
authors.forename: Kenji
authors.initials: K
authors.lastname: Aoki
mesh_terms: D000222:Adaptation, Physiological; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology; D008401:Gas Chromatography-Mass Spectrometry; D007850:Lauric Acids / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D008744:Methylamines / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D011549:Pseudomonas / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism* / Q000494:pharmacology*; D012722:Sewage / Q000382:microbiology; D014871:Water Microbiology
chemical_list: D000900:Anti-Bacterial Agents; D007850:Lauric Acids; D008744:Methylamines; D000644:Quaternary Ammonium Compounds; D012722:Sewage; C030358:lauric acid; C022806:dodecyltrimethylammonium; C023336:trimethylamine