Research & Development Institute, TAKENAKA Corporation, 1-5-1 Otsuka, Inzai, Chiba, Japan; Division of Sustainable Energy and Environment Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan.
Research & Development Institute, TAKENAKA Corporation, 1-5-1 Otsuka, Inzai, Chiba, Japan.
Chemosphere. 2022 Jan;287(Pt 1):131989. doi: 10.1016/j.chemosphere.2021.131989. Epub 2021 Aug 23.
Thermally enhanced bioremediation is a promising approach to shorten the bioremediation period of tetrachloroethene (PCE) and trichloroethene (TCE). To clarify the influence that temperature has on stepwise PCE dechlorination and associated microorganisms, this study conducted dechlorination experiments using contaminated soil and groundwater under five distinct temperature conditions (i.e., 15, 20, 25, 30, and 35 °C). PCE and TCE were dechlorinated most rapidly at 25-35 °C, whereas the preferable temperatures for the dechlorination of cis-1,2- dichloroethene (cis-1,2-DCE) and vinyl chloride (VC) were 25-30 °C and 25 °C, respectively. Microbial community analysis revealed that Sulfurospirillum and Geobacter may have a dominant contribution to the dechlorination of PCE to cis-1,2-DCE, whereas Dehalococcoides harboring VC reductase genes are likely major contributors to the dechlorination of cis-1,2-DCE and VC. These results suggest that temperature influences various microbial groups, including major dechlorinating microorganisms, resulting in the different extent of PCE dechlorination. In addition, the microbial community structure greatly changed after the onset of the experiment, whereas the temperature influence of 15-30 °C on the microbial community structure was minor; however, the microbial community was significantly impacted at 35 °C. Collectively, these results suggest that thermally enhanced anaerobic dechlorination at 25 °C is useful for successful dechlorination of chlorinated ethenes in a short period.
热强化生物修复是缩短四氯乙烯（PCE）和三氯乙烯（TCE）生物修复周期的一种很有前途的方法。为了阐明温度对逐步脱氯和相关微生物的影响，本研究在五种不同温度条件（即 15、20、25、30 和 35°C）下，使用受污染的土壤和地下水进行了脱氯实验。PCE 和 TCE 在 25-35°C 下脱氯最快，而顺式-1,2-二氯乙烯（顺式-1,2-DCE）和氯乙烯（VC）的最佳脱氯温度分别为 25-30°C 和 25°C。微生物群落分析表明，硫螺旋菌和地杆菌可能对 PCE 向顺式-1,2-DCE 的脱氯有主要贡献，而含有 VC 还原酶基因的脱氯球菌可能是顺式-1,2-DCE 和 VC 脱氯的主要贡献者。这些结果表明，温度影响包括主要脱氯微生物在内的各种微生物群体，导致 PCE 脱氯程度不同。此外，实验开始后微生物群落结构发生了很大变化，而 15-30°C 对微生物群落结构的温度影响较小；然而，35°C 对微生物群落有显著影响。总的来说，这些结果表明，25°C 的热强化厌氧脱氯对于在短时间内成功脱氯氯代烯烃是有用的。
