title: Degradation of bromoxynil octanoate by strain Acinetobacter sp. XB2 isolated from contaminated soil.
abstract: Bromoxynil octanoate (BOO), the most widespread herbicide applied to maize, is potentially toxic to both animals and humans. In this article, a highly effective BOO-degrading bacterial strain, XB2, was isolated from the soil of a herbicide factory. The strain was identified as an Acinetobacter sp. based on its 16S rRNA gene sequence analysis, morphological, physiological, and biochemical properties. This strain could use BOO as its sole carbon source and could degrade 100 mg l(-1) BOO to non-detectable levels in 72 h (h). The optimal pH and temperature for strain XB2's growth and degradation of BOO in MSM are 7.0 and 30°C, respectively. We propose the following pathway of BOO degradation by strain XB2: the first step is the scission of the ester bond to form bromoxynil, bromoxynil then transformed to 3,5-dibromo-4-hydroxybenzoic acid due to the hydrolysis of nitriles, and debromination finally results in the formation of 3-bromo-4-hydroxybenzoic acid. Inoculating BOO-treated soil samples with strain XB2 resulted in a higher rate of BOO degradation than in non-inoculated soil, regardless of whether the soil had previously been sterilized.
authors.affiliation: The College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, People's Republic of China.
authors.forename: Tianming
authors.initials: T
authors.lastname: Cai
authors.forename: Liwei
authors.initials: L
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Xu
authors.forename: Shu
authors.initials: S
authors.lastname: Cai
mesh_terms: D000150:Acinetobacter / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D015373:Bacterial Typing Techniques; D001711:Biotransformation; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D006540:Herbicides / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D053858:Metabolic Networks and Pathways; D008969:Molecular Sequence Data; D009570:Nitriles / Q000378:metabolism*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D013696:Temperature
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D006540:Herbicides; D009570:Nitriles; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; C028382:bromoxynil octanoate