Botton Sabrina, Parsons John R
Department of Earth Surface Processes and Materials, IBED, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands.
Biodegradation. 2007 Jun;18(3):371-81. doi: 10.1007/s10532-006-9071-9. Epub 2006 Nov 8.
The ability of indigenous bacteria to anaerobically degrade monoaromatic hydrocarbons has received attention as a potential strategy to remediate polluted aquifers. Despite the fact that iron-reducing conditions are often dominating in contaminated sediment, most of the studies have focussed on degradation of this class of pollutants with other terminal acceptors. In this work, we enriched bacteria from an iron-reducing aquifer in which a plume of pollution has developed over several decades and we show that benzene, toluene, meta- and para-xylene (BTX) could be degraded by the enriched cultures containing intrinsic iron-reducing microorganisms. To our knowledge, this is the first time that para-xylene degradation by dissimilatory iron-reducing bacteria has been reported in sediment free enrichment cultures. BTX degradation rates in enrichment cultures progressively increased in time and were found in good agreement with theoretical values calculated assuming complete BTX oxidation with Fe(II) as final electron acceptor. In addition, using labelled ((13)C(1)) benzene and toluene we could unambiguously identify intermediates of their respective degradation pathways. We provide evidence for benzene degradation via phenol formation under iron-reducing conditions, whereas toluene and meta-xylene were transformed into the corresponding benzylsuccinates.
本地细菌厌氧降解单环芳烃的能力作为修复受污染含水层的一种潜在策略已受到关注。尽管在受污染沉积物中，铁还原条件通常占主导地位，但大多数研究都集中在这类污染物与其他终端电子受体的降解方面。在这项研究中，我们从一个铁还原含水层中富集细菌，该含水层中已形成了几十年的污染羽流，并且我们发现，含有固有铁还原微生物的富集培养物能够降解苯、甲苯、间二甲苯和对二甲苯（BTX）。据我们所知，这是首次在无沉积物富集培养物中报道异化铁还原细菌降解对二甲苯。富集培养物中BTX的降解率随时间逐渐增加，并且与假设以Fe(II)作为最终电子受体完全氧化BTX计算得到的理论值高度一致。此外，使用标记的（(13)C(1)）苯和甲苯，我们能够明确鉴定出它们各自降解途径的中间产物。我们提供了证据，表明在铁还原条件下，苯通过生成苯酚进行降解，而甲苯和间二甲苯则转化为相应的苄基琥珀酸盐。
