REDUCTIVE DECHLORINATION OF HIGH-CONCENTRATIONS OF TETRACHLOROETHENE TO ETHENE BY AN ANAEROBIC ENRICHMENT CULTURE IN THE ABSENCE OF METHANOGENESIS
REDUCTIVE DECHLORINATION OF HIGH-CONCENTRATIONS OF TETRACHLOROETHENE TO ETHENE BY AN ANAEROBIC ENRICHMENT CULTURE IN THE ABSENCE OF METHANOGENESIS
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DOI：
10.1128/aem.57.8.2287-2292.1991
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发表时间：
1991-08-01
影响因子：
4.4
通讯作者：
ZINDER, SH
中科院分区：
文献类型：
--
作者：
DISTEFANO, TD;GOSSETT, JM;ZINDER, SH
四氯乙烯，也被称为全氯乙烯（PCE），是美国一种常见的地下水污染物。pce的不完全还原脱氯——导致三氯乙烯、二氯乙烯异构体和/或氯乙烯的积累——已被许多研究人员在各种产甲烷环境中观察到。以前的混合培养研究表明，完全脱氯到乙烯是可能的，尽管从氯乙烯到乙烯的最后脱氯步骤是有速率限制的，通常会持续存在大量的氯乙烯。在本研究中，厌氧甲醇-PCE富集培养被证明能够脱氯高浓度PCE到乙烯。添加浓度高达550 μ m的PCE（91毫克/升标称浓度；约55毫克/升实际水浓度）在35℃下，在2天内常规脱氯至80%乙烯和20%氯乙烯。使用的甲醇浓度大约是将PCE完全脱氯为乙烯所需的两倍。观察到的转化发生在没有甲烷生成的情况下，甲烷生成明显受到高浓度PCE的抑制。当孵育持续4天时，PCE几乎完全转化为乙烯，只有不到1%的转化为氯乙烯。电子天平表明，甲醇消耗量完全由脱氯（31%）和醋酸酯生产（69%）所占。PCE脱氯的高体积速率（高达275 μ mol/l /天）和用于脱氯的电子供体的相对大比例（约三分之一）表明还原性脱氯可以用于PCE污染场地的生物修复。
Tetrachloroethene, also known as perchloroethylene (PCE), is a common groundwater contaminant throughout the United States. The incomplete reductive dechlorination of PCE-resulting in accumulations of trichloroethene, dichloroethene isomers, and/or vinyl chloride-has been observed by many investigators in a wide variety of methanogenic environments. Previous mixed-culture studies have demonstrated that complete dechlorination to ethene is possible, although the final dechlorination step from vinyl chloride to ethene is rate limiting, with significant levels of vinyl chloride typically persisting. In this study, anaerobic methanol-PCE enrichment cultures which proved capable of dechlorinating high concentrations PCE to ethene were developed. Added concentrations of PCE as high as 550-mu-M (91-mg/liter nominal concentration; approximately 55-mg/liter actual aqueous concentration) were routinely dechlorinated to 80% ethene and 20% vinyl chloride within 2 days at 35-degrees-C. The methanol level used was approximately twice that needed for complete dechlorination of PCE to ethene. The observed transformations occurred in the absence of methanogenesis, which was apparently inhibited by the high concentrations of PCE. When incubation was allowed to proceed for as long as 4 days, virtually complete conversion of PCE to ethene resulted, with less than 1% persisting as vinyl chloride. An electron balance demonstrated that methanol consumption was completely accounted for by dechlorination (31%) and acetate production (69%). The high volumetric rates of PCE dechlorination (up to 275-mu-mol/liter/day) and the relatively large fraction (ca. one-third) of the supplied electron donor used for dechlorination suggest that reductive dechlorination could be exploited for bioremediation of PCE-contaminated sites.