High ammonia concentration inhibits archaea's activity, causing the accumulation of H₂ and acetate, which suppresses methane production in anaerobic digestion (AD). The study aimed to enhance microbial hydrogen metabolism through a side-stream hydrogen domestication (SHD) strategy, which involves applying hydrogen stimulation to a portion of the sludge separately. SHD maintained a stable methane yield of 407.5 mL/g VS at a high total ammonia nitrogen (TAN) concentration of 3.1 g/L. In contrast, the control group gradually decreased and stopped methane production at a TAN concentration of 2.3 g/L. Further analysis using enzyme activity assays, flow cytometry, and metagenomics explored the mechanisms underlying ammonia tolerance of SHD-treated group. SHD reshaped the microbial community, enriching homoacetogens and Methanosaeta-dominated methanogenic archaea. Key metabolic pathways including homoacetogenesis, butyrate degradation, propionate degradation, and methane production were enhanced. The activity of related enzymes also increased. Gene abundance in energy-generating pathways, such as glycolysis, was enhanced, ensuring adequate ATP production. Additionally, the high gene abundance of ion transport systems contributed to regulating proton imbalance and supplementing intracellular K⁺. This study provides important insights and practical guidance for developing novel techniques in the field of anaerobic digestion.

中文翻译：

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通过侧流氢驯化改善氨胁迫下食物垃圾的厌氧消化


高氨浓度会抑制古细菌的活性，导致 H₂ 和乙酸盐的积累，从而抑制厌氧消化 （AD） 中甲烷的产生。该研究旨在通过侧流氢驯化 （SHD） 策略增强微生物氢代谢，该策略涉及分别对一部分污泥进行氢刺激。SHD 保持了稳定的甲烷产率，为 407.5 mL/g，而总氨氮 （TAN） 浓度高达 3.1 g/L。相比之下，对照组逐渐减少并在 TAN 浓度为 2.3 g/L 时停止甲烷产生。使用酶活性测定、流式细胞术和宏基因组学进行进一步分析，探讨了 SHD 处理组氨耐受性的潜在机制。SHD 重塑了微生物群落，富集了同乙原和甲烷aeta主导的产甲烷古细菌。包括同源乙酸生成、丁酸盐降解、丙酸盐降解和甲烷产生在内的关键代谢途径得到增强。相关酶的活性也增加。能量产生途径（如糖酵解）中的基因丰度得到增强，确保足够的 ATP 产生。此外，离子转运系统的高基因丰度有助于调节质子失衡和补充细胞内 K⁺。本研究为厌氧消化领域的新技术开发提供了重要的见解和实践指导。