Di Franca Maria L, Matturro Bruna, Crognale Simona, Zeppilli Marco, Dell'Armi Edoardo, Majone Mauro, Petrangeli Papini Marco, Rossetti Simona
Water Research Institute-National Research Council (IRSA-CNR), Rome, Italy.
Department of Chemistry, Sapienza University of Rome, Rome, Italy.
Front Microbiol. 2022 Jul 18;13:951911. doi: 10.3389/fmicb.2022.951911. eCollection 2022.
Chlorinated solvents still represent an environmental concern that requires sustainable and innovative bioremediation strategies. This study describes the microbiome composition of a novel bioelectrochemical system (BES) based on sequential reductive/oxidative dechlorination for complete perchloroethylene (PCE) removal occurring in two separate but sequential chambers. The BES has been tested under various feeding compositions [i.e., anaerobic mineral medium (MM), synthetic groundwater (SG), and real groundwater (RG)] differing in presence of sulfate, nitrate, and iron (III). In addition, the main biomarkers of the dechlorination process have been monitored in the system under various conditions. Among them, and reductive dehalogenase genes (, , and ) involved in anaerobic dechlorination have been quantified. The and genes involved in aerobic dechlorination have also been quantified. The feeding composition affected the microbiome, in particular when the BES was fed with RG. , enriched in the reductive compartment, operated with MM and SG, suggesting complex interactions in the sulfur cycle mostly including sulfur oxidation occurring at the anodic counter electrode (MM) or coupled to nitrate reduction (SG). Moreover, the known responsible for natural attenuation of VC by aerobic degradation was found abundant in the oxidative compartment fed with RG, which was in line with the high VC removal observed (92 ± 2%). was observed in all the tested conditions ranging from 8.78E + 06 (with RG) to 2.35E + 07 (with MM) 16S rRNA gene copies/L. was found as the most abundant reductive dehalogenase gene in all the conditions explored (up to 2.46 E + 07 gene copies/L in MM). The microbiome dynamics and the occurrence of biomarkers of dechlorination, along with the kinetic performance of the system under various feeding conditions, suggested promising implications for the scale-up of the BES, which couples reductive with oxidative dechlorination to ensure the complete removal of highly chlorinated ethylene and mobile low-chlorinated by-products.
氯化溶剂仍然是一个环境问题，需要可持续和创新的生物修复策略。本研究描述了一种新型生物电化学系统（BES）的微生物群落组成，该系统基于顺序还原/氧化脱氯，可在两个独立但顺序的腔室中完全去除全氯乙烯（PCE）。该BES已在各种进料组成[即厌氧矿物培养基（MM）、合成地下水（SG）和真实地下水（RG）]下进行测试，这些进料组成在硫酸盐、硝酸盐和铁（III）的存在方面有所不同。此外，还在各种条件下监测了该系统中脱氯过程的主要生物标志物。其中，参与厌氧脱氯的还原脱卤酶基因（、和）已被定量。参与好氧脱氯的和基因也已被定量。进料组成影响了微生物群落，特别是当BES用RG进料时。在还原区富集，在MM和SG条件下运行，表明硫循环中存在复杂的相互作用，主要包括在阳极对电极（MM）处发生的硫氧化或与硝酸盐还原耦合（SG）。此外，已知通过好氧降解对VC进行自然衰减的在以RG进料的氧化区中含量丰富，这与观察到的高VC去除率（92±2%）一致。在所有测试条件下均观察到，16S rRNA基因拷贝数/L范围从用RG时的8.78E + 06到用MM时的2.35E + 07。在所有探索的条件下，被发现是最丰富的还原脱卤酶基因（在MM中高达2.46 E + 07基因拷贝数/L）。微生物群落动态和脱氯生物标志物的出现，以及该系统在各种进料条件下的动力学性能，表明该BES扩大规模具有广阔前景，该系统将还原脱氯与氧化脱氯相结合，以确保完全去除高氯乙烯和可移动的低氯副产物。
