The enhancement of electron or proton transfer between syntrophic microbes has been widely recognised as a means for improving methane generation. However, the uncoupled supplementation of electrons and protons in multiphase anaerobic environment hinders the balanced uptake of electrons and protons in the cytoplasm of methanogens, limiting methanogenesis efficiency. Herein, the cooperative effect of a proton-conductive material (PM) and an electron-conductive material (EM) in enhancing proton-coupled electron transfer (PCET) and driving efficient methanogenesis in anaerobic digestion was investigated. The cooperation of the PM and EM significantly increased methane production and the maximum methane generation rate by 78.9 % and 103.5 %, respectively, indicating enhanced methanogenesis efficiency. Analysis of the physicochemical properties, biochemical components, and microbial dynamics revealed that the cooperation of the PM and EM improved the metabolism of syntrophic microbes, which was critically dependent on electron and proton transfer. This enhancement was primarily due to the improvement in PCET, as mainly supported by hydrogen/deuterium kinetic isotope effect measurements, multi-omics integration analyses and reaction thermodynamics and kinetics analyses. Our findings suggest that the PCET enhancement stimulated efficient membrane-bound enzymatic reactions related to electron-driven proton translocation and facilitated electron and proton supply for CO2 reduction to realise highly efficient methane generation. These findings are expected to provide a new insight into effective electron and proton coupling transfer for methanogenic metabolism in multiphase anaerobic environments.

中文翻译：

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增强质子耦合电子转移驱动厌氧消化中的高效甲烷生成


增强共养微生物之间的电子或质子转移已被广泛认为是改善甲烷生成的一种手段。然而，在多相厌氧环境中电子和质子的解偶联补充阻碍了产甲烷菌细胞质中电子和质子的平衡摄取，限制了甲烷生成效率。在此，研究了质子导电材料 （PM） 和电子导电材料 （EM） 在增强质子耦合电子转移 （PCET） 和驱动厌氧消化中有效甲烷生成方面的协同作用。PM 和 EM 的合作显着提高了甲烷产量和最大甲烷生成速率，分别提高了 78.9% 和 103.5%，表明甲烷生成效率提高。对物理化学性质、生化成分和微生物动力学的分析表明，PM 和 EM 的合作改善了共养微生物的代谢，这严重依赖于电子和质子转移。这种增强主要是由于 PCET 的改进，主要由氢/氘动力学同位素效应测量、多组学整合分析以及反应热力学和动力学分析提供支持。我们的研究结果表明，PCET 增强刺激了与电子驱动的质子易位相关的有效膜结合酶反应，并促进了电子和质子供应以还原 CO2，从而实现高效的甲烷生成。这些发现有望为多相厌氧环境中产甲烷代谢的有效电子和质子耦合转移提供新的见解。