Direct interspecies electron transfer (DIET) between electricigens and methanogens has been shown to favour CO₂ reduction to produce biomethane. Furthermore, DIET is accelerated by conductive materials. However, whether conductive materials can promote other methanogenic pathways is unclear due to a lack of detailed experimental data and the poor mechanistic studies. Here, we hypothesized that conductive carbon nanotubes (CNTs) stimulate acetoclastic methanogenesis independently of electricigens in pure cultures of Methanosarcina spp. and anaerobic wetland soil. We found a significant increase in the methane production rate during the growth phase, e.g. from 0.169 mM to 0.241 mM after addition of CNTs on the 3rd day. CNTs did not increase the abundance of electromicroorganisms or the electron transfer rate in anaerobic soils, using via microbial diversity and electrochemical analysis. ¹³C–CH₃COOH labelling, stable carbon isotope fractionation and the CH₃F inhibitor of acetoclastic methanogenesis were used to distinguish methanogenic pathways. CNTs mainly accelerated acetoclastic methanogenesis rather than CO₂ reduction in both pure cultures and anaerobic soils. Furthermore, the presence of CNTs slightly alleviate the inhibition of CH₃F on acetoclastic methanogenesis during the pure culture of Methanosarcina barkeri and Methanosarcina mazei with the production of more than 0.3 mM methane. CNTs closely attached to the cell surface were observed by transmission electron microscopy. Proteome analysis revealed a stimulation of protein synthesis with about twice the improvement involved in –COOH oxidation and electron transfer. Overall, our findings demonstrate that conducting CNTs favor methane production and that the mechanism involved is acetoclastic methanogenesis via acetate dismutation, at least partly, rather than classical CO₂ reduction.

已经证明，电试剂和产甲烷菌之间的直接种间电子转移（DIET）有利于还原CO ₂以产生生物甲烷。此外，通过导电材料加速了DIET。然而，由于缺乏详细的实验数据和较差的机理研究，导电材料是否可以促进其他产甲烷途径尚不清楚。在这里，我们假设，导电碳纳米管（CNT）中的纯培养物独立地刺激electricigens的乙酸分解产甲烷甲烷八叠球菌spp。和厌氧湿地土壤。我们发现，在生长阶段，甲烷的生产率显着提高，例如在第三天添加CNT后，甲烷的生产率从0.169 mM增至0.241 mM。通过微生物多样性和电化学分析，CNTs不会增加厌氧土壤中微生物的丰度或电子传递速率。^使用13 C–CH ₃ COOH标记，稳定的碳同位素分级分离和乙酰碎屑甲烷化作用的CH ₃ F抑制剂来区分产甲烷途径。在纯培养物和厌氧土壤中，碳纳米管主要促进乙酰破破膜甲烷生成，而不是减少CO ₂。此外，CNT的存在稍微减轻了对CH ₃的抑制F对产甲烷巴氏甲烷八叠球菌和马氏甲烷八叠球菌纯培养期间产生超过0.3 mM甲烷的乙酰碎屑甲烷化作用有影响。通过透射电子显微镜观察到紧密附着于细胞表面的CNT。蛋白质组学分析显示，与–COOH氧化和电子转移相比，蛋白质合成的刺激作用提高了约两倍。总的来说，我们的发现表明，进行碳纳米管有利于甲烷的产生，并且所涉及的机制是通过乙酸酯歧化（至少部分地）而不是经典的CO ₂还原来进行碎屑甲烷化。