Although two-stage anaerobic digestion (TSAD) technology has been investigated, the mechanisms regarding the impact of acidogenic off-gas (AOG) on successive methane production have not been well addressed. In this study, a novel TSAD system was designed. Food waste, as the main substrate, was co-digested with chicken manure and corn straw. The acidogenic gas beyond atmospheric pressure was introduced into the bottom of the methanogenesis reactor through a stainless steel diffuser. Results showed the addition of AOG increased the methane yield from 435.2 to 597.1 mL/g VS in successive methanogenesis stage, improved by 37.2 %, and increased the energy yield from 9.0 to 11.3 kJ/g VS. However, the theoretical contribution of hydrogenotrophic methanogenesis using H contained in AOG was only 15.2 % of the increased methane yield. After the addition of AOG, the decreased levels of ammonia nitrogen and butyrate indicate that the stability of the AD system was improved. The electron transfer system and co-enzyme F420 activity were enhanced; however, the decrease in acetate kinase activity indicates aceticlastic methanogenesis may have been weakened. The microbial diversity and species richness were improved by the added AOG. was more competitive than , enhancing the syntrophic effect. The relative abundance of protein degradation bacteria and lipid degradation bacteria was increased. Metabolite analysis confirmed that the addition of AOG promoted amino acid metabolism, the biosynthesis of other secondary metabolism and lipid metabolism. The improved degradation of recalcitrant organic components (lipids and proteins) in food waste was responsible for the increased methane yield. This study provides an in-depth understanding of the impact of AOG utilization on successive methane production and has practical implications for the treatment of food waste.

中文翻译：

---

全面了解产酸尾气利用对两级厌氧消化过程中连续沼气产量、微生物群落结构和代谢物分布的影响

尽管已经研究了两级厌氧消化（TSAD）技术，但产酸废气（AOG）对连续甲烷生产的影响机制尚未得到很好的解决。在这项研究中，设计了一种新颖的 TSAD 系统。餐厨垃圾作为主要底物，与鸡粪、玉米秸秆共同消化。超过大气压的产酸气体通过不锈钢扩散器引入产甲烷反应器底部。结果表明，AOG的添加使连续产甲烷阶段的甲烷产量从435.2 mL/g VS提高到597.1 mL/g VS，提高了37.2%，能量产率从9.0 kJ/g VS提高到11.3 kJ/g VS。然而，利用AOG中所含的H进行氢营养产甲烷的理论贡献仅为增加的甲烷产量的15.2%。添加AOG后，氨氮和丁酸盐水平下降，表明AD体系的稳定性得到提高。电子传递系统和辅酶F420活性增强；然而，乙酸激酶活性的降低表明乙酸分解产甲烷作用可能已减弱。 AOG的添加提高了微生物多样性和物种丰富度。比 更具竞争力，增强了互养效应。蛋白质降解菌和脂质降解菌的相对丰度增加。代谢分析证实，AOG的添加促进了氨基酸代谢、其他次生代谢的生物合成以及脂质代谢。食物垃圾中难降解有机成分（脂质和蛋白质）的降解得到改善，是甲烷产量增加的原因。这项研究深入了解了 AOG 利用对连续甲烷生产的影响，并对食物垃圾的处理具有实际意义。