Trichloroethene (TCE) and 1,1,1-trichloroethane (1,1,1-TCA) are notorious pollutants in groundwater. The biodegradation of them yields more toxic vinyl chloride (VC) and 1,1-dichloroethene (1,1-DCE). Although their biodegradation is highly feasible in the lab, field remediation still faces huge challenges. One challenge of them is the lack of good microbial indicators and consequently, monitoring famous species can cause the prediction of project time span and related expenses to fail. Here, in this study, we offer a solution by integrating predominance, correlation, and principal component analysis on the testing results of the biodegradation of VC and 1,1-DCE under seven different nutrient-amendment conditions. The inoculum was from a contaminated site with accumulated 1,1-DCE and VC. Next-generation sequencing (NGS) was applied to 15 microbial communities. Traditional analysis relying predominance on NGS data may be misleading due to the variation of copy number per cell for different microorganisms. By considering predominance, correlation between copy number and removal efficiency, and PCA loading factors of the principle component analysis, bacteria of the Ruminococcaceae family, Syntrophomonas sp., Pseudomonas stutzuri, Candidatus Methanoregula, and Methanospirillum sp. could be microbial indicators for removing 1,1-DCE and VC in biodegradation. The results suggested a variety of combinations of bacteria and archaeal species can effectively remove 1,1-DCE but less so for VC. The influence of archaeal species in the natural environment on bioremediation of chlorinated solvents cannot be neglected.

中文翻译：

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潜在的微生物指标，可以更好地修复受氯乙烯或1,1-二氯乙烯污染的含水层

三氯乙烯（TCE）和1,1,1-三氯乙烷（1,1,1-TCA）是地下水中臭名昭著的污染物。它们的生物降解产生更具毒性的氯乙烯（VC）和1,1-二氯乙烯（1,1-DCE）。尽管它们的生物降解在实验室中是高度可行的，但现场修复仍面临巨大挑战。它们的挑战之一是缺乏良好的微生物指标，因此，监测著名物种会导致对项目时间跨度和相关费用的预测失败。在这里，在这项研究中，我们通过综合优势，相关性和主成分分析，提供了在七个不同养分修正条件下VC和1,1-DCE生物降解测试结果的解决方案。接种物来自受污染的地方，积累了1,1-DCE和VC。下一代测序（NGS）已应用于15个微生物群落。依赖于NGS数据的传统分析可能会产生误导，因为不同微生物每个细胞的拷贝数会发生变化。通过考虑优势，拷贝数与去除效率之间的相关性以及主成分分析的PCA加载因子，Ruminococcaceae家庭，Syntrophomonas属，假单胞菌stutzuri，暂定Methanoregula和Methanospirillum SP。可能是在生物降解中去除1,1-DCE和VC的微生物指标。结果表明，细菌和古细菌种类的多种组合可以有效去除1,1-DCE，但对VC则效果不明显。自然环境中古细菌物种对氯代溶剂生物修复的影响不可忽略。