Biodegradation. 2014 Jun;25(3):459-78. doi: 10.1007/s10532-013-9674-x.
Microcosm studies investigated the effects of bioaugmentation with a mixed Dehalococcoides (Dhc)/Dehalobacter (Dhb) culture on biological enhanced reductive dechlorination for treatment of 1,1,1-trichloroethane (TCA) and chloroethenes in groundwater at three Danish sites. Microcosms were amended with lactate as electron donor and monitored over 600 days. Experimental variables included bioaugmentation, TCA concentration, and presence/absence of chloroethenes. Bioaugmented microcosms received a mixture of the Dhc culture KB-1 and Dhb culture ACT-3. To investigate effects of substrate concentration, microcosms were amended with various concentrations of chloroethanes (TCA or monochloroethane [CA]) and/or chloroethenes (tetrachloroethene [PCE], trichloroethene [TCE], or 1,1-dichloroethene [1,1-DCE]). Results showed that combined electron donor addition and bioaugmentation stimulated dechlorination of TCA and 1,1-dichloroethane (1,1-DCA) to CA, and dechlorination of PCE, TCE, 1,1-DCE and cDCE to ethane. Dechlorination of CA was not observed. Bioaugmentation improved the rate and extent of TCA and 1,1-DCA dechlorination at two sites, but did not accelerate dechlorination at a third site where geochemical conditions were reducing and Dhc and Dhb were indigenous. TCA at initial concentrations of 5 mg/L inhibited (i.e., slowed the rate of) TCA dechlorination, TCE dechlorination, donor fermentation, and methanogenesis. 1 mg/L TCA did not inhibit dechlorination of TCA, TCE or cDCE. Moreover, complete dechlorination of PCE to ethene was observed in the presence of 3.2 mg/L TCA. In contrast to some prior reports, these studies indicate that low part-per million levels of TCA (< 3 mg/L) in aquifer systems do not inhibit dechlorination of PCE or TCE to ethene. In addition, the results show that co-bioaugmentation with Dhc and Dhb cultures can be an effective strategy for accelerating treatment of chloroethane/chloroethene mixtures in groundwater, with the exception that all currently known Dhc and Dhb cultures cannot treat CA.
微宇宙研究考察了用混合的 Dehalococcoides（Dhc）/Dehalobacter（Dhb）培养物进行生物增强还原脱氯对丹麦三个地点地下水中 1,1,1-三氯乙烷（TCA）和氯代烯烃处理的影响。微宇宙用乳酸作为电子供体进行了添加，并监测了 600 多天。实验变量包括生物增强、TCA 浓度以及氯代烯烃的存在/不存在。生物增强的微宇宙接受了 Dhc 培养物 KB-1 和 Dhb 培养物 ACT-3 的混合物。为了研究基质浓度的影响，微宇宙用各种浓度的氯代烯烃（TCA 或氯甲烷 [CA]）和/或氯代烯烃（四氯乙烯 [PCE]、三氯乙烯 [TCE]或 1,1-二氯乙烯 [1,1-DCE]）进行了添加。结果表明，联合电子供体添加和生物增强刺激了 TCA 和 1,1-二氯乙烷（1,1-DCA）向 CA 的脱氯，以及 PCE、TCE、1,1-DCE 和 cDCE 向乙烷的脱氯。未观察到 CA 的脱氯。在两个地点，生物增强提高了 TCA 和 1,1-DCA 脱氯的速率和程度，但在第三个地点没有加速脱氯，该地点的地球化学条件是还原的，并且 Dhc 和 Dhb 是本土的。初始浓度为 5mg/L 的 TCA 抑制了（即减缓了）TCA 脱氯、TCE 脱氯、供体发酵和产甲烷作用。1mg/L 的 TCA 不会抑制 TCA、TCE 或 cDCE 的脱氯。此外，在 3.2mg/L TCA 的存在下，完全将 PCE 脱氯为乙烯。与一些先前的报告相反，这些研究表明，含水层系统中低至百万分之几的 TCA（<3mg/L）水平不会抑制 PCE 或 TCE 向乙烯的脱氯。此外，结果表明，用 Dhc 和 Dhb 培养物共同生物增强是加速地下水氯代烃/氯代烯烃混合物处理的有效策略，只是目前已知的所有 Dhc 和 Dhb 培养物都不能处理 CA。
