Anaerobic digestion (AD) of food waste (FW) tends to result in the accumulation of volatile fatty acids (VFA), especially a large quantity of propionic acid that is inevitably produced. Propionic acid has a significant inhibitory effect on AD at a concentration far lower than acetic acid. Therefore, anaerobic digestion cannot be operated at an excessively high load. We proposed an AD system that used a considerable amount of starch-rich food waste for ethanol fermentation as a pretreatment and reported that it improved methane concentration in biogas with a low propionic acid accumulation even under high-load operation. This study examined whether ethanol fermentation pretreatment (EP) of food waste can contribute to high-load operation on AD using an anaerobic membrane bioreactor (AnMBR). This involved a sequential bath experiment using FW that was saccharized before fermentation to ethanol. The results are compared with those for FW without pretreatment. The organic loading rate (OLR) was stepwise increased to 43.5 g COD/L/d by increasing the feed OLR, the hydraulic retention time (HRT) was six days and methane content was 71%–74%, which is thrice the capability of the control series and the highest load in the reports of medium temperature AD of FW. Furthermore, the primary methanogens were tolerant to ammonia inhibition. Correspondingly, the ammonium produced improved the buffering capacity of AD at high load. Functional archaeal and bacterial communities in the two reactors were examined. The abundance of hydrogenotrophic methanogens in AnMBR are determined to highlight the impact of the EP for FW disposal through 16S rRNA sequence analysis. Because there were multiple methanogens that use hydrogen, the higher decomposition of the substrate was attributable to the maintenance of a lower hydrogen partial pressure. It contributed to create a virtuous cycle with the EP. This study demonstrates the performance of the EP during high loading and long-term AD operation using an AnMBR; moreover, ultra-high load is achieved by changing the metabolic pathway.

食物垃圾 (FW) 的厌氧消化 (AD) 往往会导致挥发性脂肪酸 (VFA) 的积累，尤其是不可避免地产生大量丙酸。丙酸在远低于乙酸的浓度下对AD有显着的抑制作用。因此，不能在过高负荷下进行厌氧消化。我们提出了一种 AD 系统，该系统使用大量富含淀粉的食物垃圾进行乙醇发酵作为预处理，并报告说即使在高负荷运行下，它也能以低丙酸积累提高沼气中的甲烷浓度。本研究检验了使用厌氧膜生物反应器 (AnMBR) 对餐厨垃圾进行乙醇发酵预处理 (EP) 是否有助于 AD 的高负荷运行。这涉及使用在发酵成乙醇之前糖化的 FW 的连续浴实验。将结果与未经预处理的 FW 的结果进行比较。通过增加进料OLR，有机负荷率(OLR)逐步提高到43.5 g COD/L/d，水力停留时间(HRT)为6天，甲烷含量为71%–74%，是能力的三倍。 FW 的介质温度 AD 报告中的控制系列和最高负载。此外，主要产甲烷菌对氨抑制具有耐受性。相应地，产生的铵提高了高负荷下 AD 的缓冲能力。检查了两个反应器中的功能古菌和细菌群落。AnMBR 中氢营养产甲烷菌的丰度被确定为通过 16S rRNA 序列分析突出 EP 对 FW 处理的影响。由于存在多种使用氢气的产甲烷菌，底物的较高分解归因于维持较低的氢气分压。它有助于与 EP 形成良性循环。本研究使用 AnMBR 证明了 EP 在高负载和长期 AD 操作期间的性能；此外，通过改变代谢途径实现超高负荷。本研究使用 AnMBR 证明了 EP 在高负载和长期 AD 操作期间的性能；此外，通过改变代谢途径实现超高负荷。本研究使用 AnMBR 证明了 EP 在高负载和长期 AD 操作期间的性能；此外，通过改变代谢途径实现超高负荷。