Anaerobic biotransformation of roxarsone and related N-substituted phenylarsonic acids
Anaerobic biotransformation of roxarsone and related N-substituted phenylarsonic acids
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DOI：
10.1021/es051981o
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发表时间：
2006-05-01
影响因子：
11.4
通讯作者：
Sierra-Alvarez, R
中科院分区：
文献类型：
--
作者：
Cortinas, I;Field, JA;Sierra-Alvarez, R
大量的砷是通过在土地上施用含有有机砷饲料添加剂洛克沙胂（3-硝基-4-羟基苯胂酸）的家禽粪便进入环境的。本研究的目的是评估洛克沙胂和相关的N-取代苯胂酸衍生物在厌氧条件下的生物转化。结果表明，洛克沙胂在无氧条件下迅速转化为相应的芳香胺4-羟基-3-氨基苯胂酸（HAPA）。HAPA的形成归因于硝基的容易还原。供电子底物，如氢气，葡萄糖和乳酸，刺激硝基还原的速率，表明微生物的作用。在长期培养过程中，HAPA和密切相关的4-氨基苯胂酸（4-阿帕）在产甲烷和硫酸盐还原条件下被缓慢生物消除高达99%，而很少或没有去除发生在热灭活接种物对照，亚砷酸盐，并在较小程度上，砷酸盐被观察到的降解产物。游离形式的无机砷物种占19-28%的氨基取代的苯胂酸删除。这构成了第一个报告的生物催化断裂的苯胂基在厌氧条件下。
Large quantities of arsenic are introduced into the environment through land application of poultry litter containing the organoarsenical feed additive roxarsone (3-nitro-4-hydroxyphenylarsonic acid). The objective of this study was to evaluate the bioconversion of roxarsone and related N-substituted phenylarsonic acid derivatives under anaerobic conditions. The results demonstrate that roxarsone is rapidly transformed in the absence of oxygen to the corresponding aromatic amine, 4-hydroxy-3aminophenylarsonic acid (HAPA). The formation of HAPA is attributable to the facile reduction of the nitro group. Electron-donating substrates, such as hydrogen gas, glucose, and lactate, stimulated the rate of nitro group reduction, indicating a microbial role. During long-term incubations, HAPA and the closely related 4-aminophenylarsonic acid (4-APA) were slowly biologically eliminated by up to 99% under methanogenic and sulfate-reducing conditions, whereas little or no removal occurred in heat-killed inoculum controls, Arsenite and, to a lesser extent, arsenate were observed as products of the degradation. Freely soluble forms of the inorganic arsenical species accounted for 19-28% of the amino-substituted phenylarsonic acids removed. This constitutes the first report of a biologically catalyzed rupture of the phenylarsonic group under anaerobic conditions.