Water Research Institute, National Research Council (IRSA-CNR), Via Salaria km 29.300, 00015 Monterotondo, RM, Italy.
N Biotechnol. 2013 Sep 25;30(6):749-55. doi: 10.1016/j.nbt.2013.04.003. Epub 2013 Apr 26.
This study investigated the feasibility of using a polarized graphite electrode as direct or indirect (via electrolytic oxygen generation) electron acceptor to stimulate the microbial oxidation of cis-dichloroethene (cis-DCE) in contaminated groundwater. A microbial culture was enriched in the anode chamber of a bioelectrochemical cell using a mixture of cis-DCE and ethene as substrates. The bioelectrochemical cell was operated by controlling the anode potential at +1.0 V or +1.5 V versus the standard hydrogen electrode (SHE). Enhanced cometabolic removal of cis-DCE, with ethene serving as the growth substrate, was observed in batch tests with the anode polarized at +1.5 V versus SHE. At this potential, (chloro)ethenes removal was probably sustained by molecular oxygen generated at the anode from water oxidation. Conversely, negligible anaerobic degradation was observed at +1.0 V versus SHE (a potential which does not allow oxygen generation), hence suggesting that molecular oxygen is needed to initiate (chloro)ethene degradation. PCR-DGGE analysis of the microbial culture followed by band sequencing and phylogenetic analysis evidenced the selective enrichment of a Bacillus species, providing a strong indication that this microorganism was responsible for cis-DCE and ethene degradation.
本研究探讨了使用极化石墨电极作为直接或间接（通过电解氧气生成）电子受体来刺激受污染地下水中顺式-二氯乙烯（cis-DCE）微生物氧化的可行性。在生物电化学电池的阳极室中，使用 cis-DCE 和乙烯的混合物作为底物来富集微生物培养物。通过控制阳极相对于标准氢电极（SHE）的电位为+1.0 V 或+1.5 V 来操作生物电化学电池。在阳极相对于 SHE 极化至+1.5 V 的批处理测试中，观察到 cis-DCE 的增强共代谢去除，其中乙烯作为生长底物。在这种电位下，（氯）乙烯的去除可能是由阳极从水中氧化产生的分子氧维持的。相反，在+1.0 V 相对于 SHE（不允许氧气生成的电位）时，观察到可忽略不计的厌氧降解，因此表明需要分子氧来引发（氯）乙烯的降解。对微生物培养物进行 PCR-DGGE 分析，然后进行带测序和系统发育分析，证明了一种芽孢杆菌的选择性富集，这强烈表明该微生物负责 cis-DCE 和乙烯的降解。
