Lignin intermediates resulting from lignocellulose degradation have been suspected to hinder anaerobic mineralisation of organic materials to biogas. Phenyl acids like phenylacetate (PAA) are early detectable intermediates during anaerobic digestion (AD) of aromatic compounds. Studying the phenyl acid formation dynamics and concomitant microbial community shifts can help to understand the microbial interdependencies during AD of aromatic compounds and may be beneficial to counteract disturbances. The length of the aliphatic side chain and chemical structure of the benzene side group(s) had an influence on the methanogenic system. PAA, phenylpropionate (PPA), and phenylbutyrate (PBA) accumulations showed that the respective lignin intermediate was degraded but that there were metabolic restrictions as the phenyl acids were not effectively processed. Metagenomic analyses confirmed that mesophilic genera like Fastidiosipila or Syntrophomonas and thermophilic genera like Lactobacillus, Bacillus, Geobacillus, and Tissierella are associated with phenyl acid formation. Acetoclastic methanogenesis was prevalent in mesophilic samples at low and medium overload conditions, whereas Methanoculleus spp. dominated at high overload conditions when methane production was restricted. In medium carbon load reactors under thermophilic conditions, syntrophic acetate oxidation (SAO)-induced hydrogenotrophic methanogenesis was the most important process despite the fact that acetoclastic methanogenesis would thermodynamically be more favourable. As acetoclastic methanogens were restricted at medium and high overload conditions, syntrophic acetate oxidising bacteria and their hydrogenotrophic partners could step in for acetate consumption. PAA, PPA, and PBA were early indicators for upcoming process failures. Acetoclastic methanogens were one of the first microorganisms to be impaired by aromatic compounds, and shifts to syntrophic acetate oxidation coupled to hydrogenotrophic methanogenesis occurred in thermophilic reactors. Previously assumed associations of specific meso- and thermophilic genera with anaerobic phenyl acid formation could be confirmed.

中文翻译：

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木质素中间体导致中，高温间歇反应器中苯酸的形成和微生物群落的变化

已经怀疑由木质纤维素降解产生的木质素中间体会阻碍有机物质厌氧矿化成沼气。苯乙酸等苯酸（PAA）是芳香族化合物厌氧消化（AD）期间的早期可检测中间体。研究苯酸的形成动力学和伴随的微生物群落转移可以帮助理解芳香族化合物在AD期间的微生物相互依赖性，并且可能有助于抵消干扰。脂肪族侧链的长度和苯侧基的化学结构对产甲烷系统有影响。PAA，苯丙酸苯酯（PPA）和苯丁酸苯酯（PBA）的积累表明，相应的木质素中间体被降解，但是由于未有效处理苯酸，因此存在代谢限制。元基因组学分析证实，嗜温属（如Fastidiosipila或Syntrophomonas）和嗜热属（如乳酸杆菌，芽孢杆菌，地芽孢杆菌和提氏梭菌）与苯甲酸的形成有关。在中，低负荷条件下的嗜温样品中，破骨细胞的产甲烷作用普遍存在，而甲烷菌属。甲烷生产受到限制时，在高过载条件下占主导地位。在嗜热条件下的中碳负载反应堆中，尽管乙酰破膜甲烷生成在热力学上会更有利，但由乙酸同养氧化（SAO）诱导的氢营养甲烷化是最重要的过程。由于破骨细胞产甲烷菌在中高负荷条件下受到限制，腐殖酸乙酸盐氧化细菌及其氢营养伴侣可以介入以消耗乙酸盐。PAA，PPA和PBA是即将发生的过程故障的早期指标。破骨细胞产甲烷菌是最早被芳香族化合物破坏的微生物之一，并且在嗜热反应堆中发生了向营养性乙酸氧化转化为氢营养型甲烷生成的过程。以前假定的特定的介亲和嗜热属与厌氧苯甲酸的形成有关。