title: Biodegradation kinetics and mechanism of 2,4,6-tribromophenol by Bacillus sp. GZT: a phenomenon of xenobiotic methylation during debromination.
abstract: A strain Bacillus sp. GZT capable of debrominating and mineralizing 2,4,6-tribromophenol (TBP) was isolated and characterized by morphological observation, biochemical and physiological identification as well as 16S rRNA sequence analysis. Biodegradation kinetics experiments demonstrated that initial TBP concentration had a predominant effect on degradation efficiency. Within 120h, the highest TBP degradation and debromination efficiencies were up to 93.2% and 89.3%, respectively, under the optimum condition. Ten metabolic intermediates including five brominated compounds, three oxidative products and two cellular metabolites were all identified by gas chromatography-mass spectrometer, and six key intermediates were doubly validated by authentic standards. The proposed biodegradation mechanism inferred that reductive debromination as a major degradation pathway could simultaneously take place at ortho- and para-positions on TBP, while methylated debromination was also found as a minor degradation pathway during this process. Within 148h degradation, nearly one-third of 3mg/L TBP could be completely mineralized.
authors.affiliation: State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Graduate School of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zu
authors.forename: Guiying
authors.initials: G
authors.lastname: Li
authors.forename: Taicheng
authors.initials: T
authors.lastname: An
authors.forename: Po-Keung
authors.initials: PK
authors.lastname: Wong
mesh_terms: D001407:Bacillus / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001966:Bromine / Q000378:metabolism*; D007700:Kinetics; D008745:Methylation; D010636:Phenols / Q000378:metabolism*; D012722:Sewage; D015262:Xenobiotics / Q000378:metabolism*
chemical_list: D010636:Phenols; D012722:Sewage; D015262:Xenobiotics; D001966:Bromine; C004554:2,4,6-tribromophenol