Conductive materials have been applied to assist syntrophic metabolism in anaerobic digestion. However, their role in the transformation of organic compounds, particularly recalcitrant compounds, has not been revealed. In this study, iron-based materials - magnetite nanoparticles and Fe2+- were employed to explore their effects on the transformation of different organic matters in anaerobic system. Prompted methane production rates and quantity in iron-based materials groups were found due to the improved solubilization of organic particles, enhanced degradation of recalcitrant compounds, and maintained microbial activity under substrate-limited conditions. Specifically, the proportion of the reducing functional groups (C-C/H or CC) and O/C ratio were always significantly lower in iron-based materials supplemented groups (Fe groups) compared to Control group, despite hydrolysis was greatly enhanced in Fe groups. The greater dehydrogenation oxidation was confirmed in the presence of iron-based materials. The remaining humic-like substances (HS), a typical type of recalcitrant compound, was about 2.5 times higher in Control group (221.2 ± 5.3 mg/L-C) compared to Fe groups after 30 days degradation. By tracking the aromaticity of HS and individual compounds at molecular level, this study reveals that iron-based materials were more effective in stimulating the degradation of aliphatic moieties than the aromatic moieties of recalcitrant compounds. When readily biodegradable substrates were limited, Fe groups continued methane generation by using recalcitrant compounds (e.g. thiethylperazine and fluvoxamino acid) as carbon source, and the microbial activity was maintained according to higher relative abundance of protonated nitrogen and continuous methanogenesis activity at starvation phase.

中文翻译：

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在铁基材料的辅助下，在饱餐和饥荒条件下，厌氧消化中有机化合物转化的微观水平评估-揭示了AD增强的真正机理。

导电材料已被用于辅助厌氧消化过程中的营养代谢。然而，尚未揭示它们在有机化合物，特别是难降解化合物的转化中的作用。在这项研究中，使用铁基材料-磁铁矿纳米颗粒和Fe2 +-来研究它们对厌氧系统中不同有机物转化的影响。由于改善了有机颗粒的溶解性，增强了难降解化合物的降解以及在底物受限的条件下保持了微生物活性，铁基材料组的甲烷生产率和数量得到了提高。具体来说，尽管铁基团的水解作用大大增强，但铁基材料添加组（Fe基团）的还原性官能团（CC / H或CC）的比例和O / C比值始终显着低于对照组。在铁基材料的存在下证实了更大的脱氢氧化。降解30天后，对照组的其余腐殖质样物质（HS）是一种典型的顽固性化合物，与Fe组相比，对照组（221.2±5.3 mg / LC）高约2.5倍。通过在分子水平上追踪HS和单个化合物的芳香性，这项研究表明，铁基材料在刺激脂肪族部分的降解上比顽固化合物的芳香族部分更有效。当易生物降解的底物受到限制时，