Abstract：
Chlorinated ethenes are toxic compounds that were widely used in the past, and their improper handling and storage caused notable pollutions worldwide. In situ bioremediation by reductive dechlorination of bacteria is a cost-effective and ecologically friendly way to eliminate these pollutions. During the present study, the efficiency of a previously developed bioaugmentation agent combined with biostimulation was tested under field conditions in contaminated soil. Furthermore, the preservation of dechlorinating ability was also investigated in a long-term experiment. Initially, aerobic conditions were present in the groundwater with possible presence of anaerobic micro-niches providing habitat for Brocadia related anammox bacteria. \"Candidatus Omnitrophus\" was also identified as a dominant member of community then. Significant changes were detected after the biostimulation, anaerobic conditions established and most of the dominant OTUs were related to fermentative taxa (e.g. Clostridium, Trichococcus and Macillibacteroides). Dominant presence of vinyl-chloride coupled with the lack of vinyl-chloride reductase gene was observed. The most notable change after the bioaugmentation was the significant decrease in the pollutant quantities and the parallel increase in the vcrA gene copy numbers. Similar to post-biostimulation state, fermentative bacteria dominated the community. Bacterial community composition transformed considerably with time after the treatment, dominance of fermentative-mainly Firmicutes related-taxa decreased and chemolithotrophic bacteria became abundant, but the dechlorinating potential of the community remained and could be induced by the reappearance of the pollutants even after 4 years.
摘要：
氯化乙烯是过去广泛使用的有毒化合物，它们的不当处理和储存在全球范围内造成了显著的污染。通过细菌的还原性脱氯进行原位生物修复是消除这些污染的一种经济有效且生态友好的方法。在本研究中,在污染土壤的田间条件下测试了先前开发的生物增强剂与生物刺激相结合的效率。此外，在长期实验中还研究了脱氯能力的保存。最初，地下水中存在有氧条件，可能存在厌氧微生态位，为Brocadia相关的厌氧氨氧化细菌提供栖息地。“CandidatusOmnitrophus”当时也被确定为社区的主要成员。生物刺激后检测到显著变化，建立的厌氧条件和大多数主要的OTU与发酵分类群有关(例如梭菌，三毛球菌和麦氏杆菌）。观察到氯乙烯的主要存在以及氯乙烯还原酶基因的缺乏。生物强化后最显着的变化是污染物数量的显着减少和vcrA基因拷贝数的平行增加。类似于生物刺激后状态，发酵细菌占主导地位的社区。治疗后，细菌群落组成随着时间的推移发生了相当大的变化，发酵-主要是Firmicutes相关分类群的优势下降，化学营养细菌变得丰富，但是社区的脱氯潜力仍然存在，即使在4年后，污染物的再次出现也可能引起。
