Department of Civil and Environmental Engineering, ‡Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117576.
Environ Sci Technol. 2011 Oct 1;45(19):8475-82. doi: 10.1021/es201559g. Epub 2011 Sep 6.
Polybrominated diphenyl ethers (PBDEs) are widespread global contaminants due to their extensive usage as flame retardants. Among the 209 PBDE congeners, tetra-brominated diphenyl ether (tetra-BDE) (congener 47) and penta-BDEs (congeners 99 and 100) are the most abundant, toxic, and bioaccumulative congeners in the environment. However, little is known about microorganisms that carry out debromination of these congeners under anaerobic conditions. In this study, we describe a coculture GY2 consisting of Dehalococcoides and Desulfovibrio spp., which is capable of debrominating ∼1180 nM of congeners 47, 99, and 100 (88-100% removal) to the nonbrominated diphenyl ether at an average rate of 36.9, 19.8, and 21.9 nM day(-1), respectively. Ortho bromines are preferentially removed during the debromination process. The growth of Dehalococcoides links tightly with PBDE debromination, with an estimated growth yield of 1.99 × 10(14) cells per mole of bromide released, while the growth of Desulfovibrio could be independent of PBDEs. The growth-coupled debromination suggests that Dehalococcoides cells in the coculture GY2 are able to respire on PBDEs. Given the ubiquity and recalcitrance of the tetra- and penta-BDEs, complete debromination of these congeners to less toxic end products (e.g. diphenyl ether) is important for the restoration of PBDE-contaminated environments.
多溴二苯醚（PBDEs）作为广泛使用的阻燃剂，在全球范围内广泛存在，是一种普遍存在的污染物。在 209 种 PBDE 同系物中，四溴二苯醚（四溴化二苯醚）（同系物 47）和五溴二苯醚（同系物 99 和 100）是环境中最丰富、毒性最大、生物累积性最强的同系物。然而，对于在厌氧条件下进行这些同系物脱溴的微生物知之甚少。在本研究中，我们描述了一种由 Dehalococcoides 和 Desulfovibrio spp.组成的共培养物 GY2，它能够将 1180 nM 的同系物 47、99 和 100（88-100%去除）脱溴为非溴化二苯醚，平均脱溴速率分别为 36.9、19.8 和 21.9 nM 天(-1)。脱溴过程中优先去除邻位溴。Dehalococcoides 的生长与 PBDE 脱溴紧密相关，估计每释放 1 摩尔溴，细胞生长的产率为 1.99×10(14)个细胞，而 Desulfovibrio 的生长可能与 PBDE 无关。这种与生长相关的脱溴表明，共培养物 GY2 中的 Dehalococcoides 细胞能够以 PBDE 为呼吸底物。鉴于四溴和五溴二苯醚的普遍存在和难降解性，将这些同系物完全脱溴为毒性较低的终产物（例如二苯醚）对于 PBDE 污染环境的修复非常重要。
