†Helmholtz-Zentrum für Umweltforschung - UFZ, Department Isotope Biogeochemistry, Permoserstrasse15, 04318 Leipzig, Germany.
‡Technische Universität Berlin, Fachgebiet Applied Biochemistry, Gustav-Meyer-Allee 25, 13355 Berlin, Germany.
Environ Sci Technol. 2015 May 19;49(10):6018-28. doi: 10.1021/acs.est.5b00303. Epub 2015 May 11.
Halogenated homo- and heterocyclic aromatics including disinfectants, pesticides and pharmaceuticals raise concern as persistent and toxic contaminants with often unknown fate. Remediation strategies and natural attenuation in anaerobic environments often build on microbial reductive dehalogenation. Here we describe the transformation of halogenated anilines, benzonitriles, phenols, methoxylated, or hydroxylated benzoic acids, pyridines, thiophenes, furoic acids, and benzenes by Dehalococcoides mccartyi strain CBDB1 and environmental fate modeling of the dehalogenation pathways. The compounds were chosen based on structural considerations to investigate the influence of functional groups present in a multitude of commercially used halogenated aromatics. Experimentally obtained growth yields were 0.1 to 5 × 10(14) cells mol(-1) of halogen released (corresponding to 0.3-15.3 g protein mol(-1) halogen), and specific enzyme activities ranged from 4.5 to 87.4 nkat mg(-1) protein. Chlorinated electron-poor pyridines were not dechlorinated in contrast to electron-rich thiophenes. Three different partial charge models demonstrated that the regioselective removal of halogens is governed by the least negative partial charge of the halogen. Microbial reaction pathways combined with computational chemistry and pertinent literature findings on Co(I) chemistry suggest that halide expulsion during reductive dehalogenation is initiated through single electron transfer from B12Co(I) to the apical halogen site.
卤代同环和杂环芳烃包括消毒剂、杀虫剂和药物，作为持久性和有毒的污染物受到关注，其归宿往往不为人知。在厌氧环境中，修复策略和自然衰减通常依赖于微生物的还原脱卤作用。在这里，我们描述了 Dehalococcoides mccartyi 菌株 CBDB1 对卤代苯胺、苯甲腈、苯酚、甲氧基化或羟基化苯甲酸、吡啶、噻吩、呋喃酸和苯的转化，以及脱卤途径的环境归宿建模。选择这些化合物是基于结构考虑，以研究存在于大量商业用卤代芳烃中的官能团的影响。实验获得的生长产率为 0.1 到 5×10(14)个细胞 mol(-1) 释放的卤化物（相当于 0.3-15.3 g 蛋白质 mol(-1) 卤化物），特定酶活性范围为 4.5 到 87.4 nkat mg(-1) 蛋白质。与富电子的噻吩不同，氯化贫电子吡啶没有脱氯。三种不同的部分电荷模型表明，卤原子的区域选择性去除受卤原子的最小负部分电荷控制。微生物反应途径结合计算化学和关于 Co(I)化学的相关文献发现表明，在还原脱卤过程中卤化物的逐出是通过 B12Co(I)向顶端卤原子位的单电子转移引发的。
