MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Science, Zhejiang University, Hangzhou, 310058, China.
MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Science, Zhejiang University, Hangzhou, 310058, China.
Environ Res. 2023 Oct 15;235:116645. doi: 10.1016/j.envres.2023.116645. Epub 2023 Jul 11.
Bioelectrochemical system is considered as a promising approach for enhanced bio-dechlorination. However, the mechanism of extracellular electron transfer in the dechlorinating consortium is still a controversial issue. In this study, bioelectrochemical systems were established with cathode potential settings at -0.30 V (vs. SHE) for trichloroethylene reduction. The average dechlorination rate (102.0 μM Cl·d) of biocathode was 1.36 times higher than that of open circuit (74.7 μM Cl·d). Electrochemical characterization via cyclic voltammetry illustrated that electrostimulation promoted electrochemical activity for redox reactions. Moreover, bacterial community structure analyses indicated electrical stimulation facilitated the enrichment of electroactive and dechlorinating populations on cathode. Metagenomic and quantitative polymerase chain reaction (qPCR) analyses revealed that direct electron transfer (via electrically conductive pili, multi-heme c-type cytochromes) between Axonexus and Desulfovibrio/cathode and indirect electron transfer (via riboflavin) for Dehalococcoides enhanced dechlorination process in BES. Overall, this study verifies the effectiveness of electrostimulated bio-dechlorination and provides novel insights into the mechanisms of dechlorination process enhancement in bioelectrochemical systems through electron transfer networks.
生物电化学系统被认为是增强生物脱氯的一种很有前途的方法。然而，脱氯菌联合体中外源电子传递的机制仍然是一个有争议的问题。在这项研究中，建立了阴极电位设置为-0.30 V（相对于 SHE）的生物电化学系统，以还原三氯乙烯。生物阴极的平均脱氯率（102.0 μM Cl·d）比开路（74.7 μM Cl·d）高 1.36 倍。通过循环伏安法进行的电化学特性表明，电刺激促进了氧化还原反应的电化学活性。此外，细菌群落结构分析表明，电刺激有利于在阴极上富集电活性和脱氯种群。宏基因组和定量聚合酶链反应（qPCR）分析表明，Axonexus 和 Desulfovibrio/cathode 之间通过导电菌毛和多血红素 c 型细胞色素进行直接电子转移（通过黄素），以及 Dehalococcoides 通过黄素进行间接电子转移，增强了 BES 中的脱氯过程。总的来说，这项研究验证了电刺激生物脱氯的有效性，并通过电子传递网络为生物电化学系统中脱氯过程增强的机制提供了新的见解。
