Anaerobic digestion (AD) is a promising technology for food waste management, but frequently restricted with long lag phase as a consequent of acidification. Two laboratory experiments were conducted to investigate the effects of iron materials on food waste AD. Experiment 1 compared the effects of iron oxide (IO) and zero valent iron (ZVI) on AD performance. The results showed that both IO and ZVI could enhance methane (CH4) generation, but IO showed better performance regarding the reduction of lag phase. The lag phase of the reactor supplemented with IO was 17.4% and 42.7% shorter than that of the reactor supplemented with ZVI and the control, respectively. Based on these results, experiment 2 was designed to examine the role of IO in alleviation of acid stress at high substrate to inoculum (SI) ratio. The results showed that supplemented IO into reactor could ensure a successful methanogenesis when operating at high SI ratio, while IO-free reactor was failed to generate CH4 although operating for 77 days. Supplementing IO into the reactor after 48 h of digestion could restore the CH4 generation, though its lag phase was 2.6 times of the reactor supplemented with IO at the beginning of the digestion. Microbial community structure analysis revealed that IO could simultaneously enrich Syntrophomonas and methanogens (i.e. Methanobacterium, Methanofollis and Methanosarcina), and might promote electron transfer between those two types of microbes, which were critical for achieving an effective methanogenesis.

中文翻译：

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氧化铁通过促进同食肉单胞菌和产甲烷菌之间的营养代谢来减轻酸胁迫。

厌氧消化（AD）是一种用于食品废物管理的有前途的技术，但由于酸化的结果，通常受制于长滞后阶段。进行了两个实验室实验，以研究铁材料对食物垃圾广告的影响。实验1比较了氧化铁（IO）和零价铁（ZVI）对AD性能的影响。结果表明，IO和ZVI均可增强甲烷（CH4）的生成，但IO在减少滞后阶段方面表现出更好的性能。补充有IO的反应器的滞后阶段分别比补充有ZVI和对照的反应器的滞后阶段短17.4％和42.7％。基于这些结果，设计了实验2，以检验IO在缓解高底物与接种物（SI）比例下酸胁迫中的作用。结果表明，当以高SI比运行时，向反应器中补充IO可以确保成功的甲烷生成，而无IO反应器尽管运行77天仍无法生成CH4。消化48小时后向反应器中添加IO可以恢复CH4的生成，尽管其滞后阶段是消化开始时添加IO的反应器的2.6倍。微生物群落结构分析表明，IO可以同时富集食肉单胞菌和产甲烷菌（即甲烷杆菌，甲烷菌和甲烷藻），并可能促进这两种微生物之间的电子转移，这对于实现有效的甲烷生成至关重要。尽管无IO反应器运行77天，但未能生成CH4。消化48小时后向反应器中补充IO可以恢复CH4的生成，尽管其滞后阶段是消化开始时补充IO的反应器的2.6倍。微生物群落结构分析表明，IO可以同时富集食肉单胞菌和产甲烷菌（即甲烷杆菌，甲烷菌和甲烷藻），并可能促进这两种微生物之间的电子转移，这对于实现有效的甲烷生成至关重要。尽管无IO反应器运行77天，但未能生成CH4。消化48小时后向反应器中补充IO可以恢复CH4的生成，尽管其滞后阶段是消化开始时补充IO的反应器的2.6倍。微生物群落结构分析表明，IO可以同时富集食肉单胞菌和产甲烷菌（即甲烷杆菌，甲烷菌和甲烷藻），并可能促进这两种微生物之间的电子转移，这对于实现有效的甲烷生成至关重要。