Aroclor 1260, a commercial polychlorinated biphenyl (PCB) mixture, is highly recalcitrant to biotransformation. A negatively polarized cathode (−0.35 V vs. standard hydrogen electrode) was applied for the first time to a marine-origin PCB dechlorinating culture that substantially increased the microbial dechlorination rate of Aroclor 1260 (from 8.6 to 11.6 μM Cl⁻ d⁻¹); meta-chlorine removal was stimulated and higher proportions of tetra-CBs (43.2–46.6%), the predominant dechlorination products, were observed compared to the open circuit conditions (23.7–25.1%). The dechlorination rate was further enhanced (14.1 μM Cl⁻ d⁻¹) by amendment with humin as a solid-phase redox mediator. After the suspension culture was renewed using an anaerobic medium, dechlorination activity was effectively maintained solely by cathodic biofilms, where cyclic voltammetry results indicated their redox activity. Electric potential had a significant effect on microbial community structure in the cathodic biofilm, where a greater abundance of Dehalococcoides (2.59–3.02%), as potential dechlorinators, was observed compared to that in the suspension culture (0.41–0.55%). Moreover, Dehalococcoides adhering to the cathode showed a higher chlorine removal rate than in the suspension culture. These findings provide insights into the dechlorination mechanism of cathodic biofilms involving Dehalococcoides for PCB mixtures and extend the application prospects of bioremediation to PCB contamination in the natural environment.

Aroclor 1260 是一种商用多氯联苯 (PCB) 混合物，对生物转化具有很强的抵抗力。负极化阴极（-0.35 V与标准氢电极）首次应用于海洋来源的 PCB 脱氯培养物，显着提高了 Aroclor 1260 的微生物脱氯率（从 8.6 到 11.6 μM C​​l ^- d ^-1） ; 与开路条件 (23.7–25.1%) 相比，间氯去除受到刺激，并且观察到更高比例的四氯化碳 (43.2–46.6%)，即主要的脱氯产物。脱氯率进一步提高（14.1 μM C​​l ^- d ^-1) 通过添加 humin 作为固相氧化还原介质。在使用厌氧培养基更新悬浮培养物后，仅通过阴极生物膜有效地维持脱氯活性，其中循环伏安法结果表明它们的氧化还原活性。电位曾在阴极生物膜，这里的更丰富的微生物群落结构的影响显著Dehalococcoides相比，在悬浮培养（0.41-0.55％）观察（2.59-3.02％），作为潜在的dechlorinators。此外，附着在阴极上的Dehalococcoides显示出比悬浮培养更高的氯去除率。这些发现提供了对涉及Dehalococcoides的阴极生物膜的脱氯机制的见解 用于 PCB 混合物，并将生物修复的应用前景扩展到自然环境中的 PCB 污染。