Department of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea.
Department of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea; Graduate School of Carbon Neutrality, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea.
Bioresour Technol. 2022 Dec;366:128205. doi: 10.1016/j.biortech.2022.128205. Epub 2022 Nov 3.
Promoting direct interspecies electron transfer (DIET) with conductive additives is considered a promising approach to enhance methanogenesis. This study investigated the effects of adding submicron magnetite particles on sludge granulation and methanogenic performance in upflow anaerobic sludge blanket reactors inoculated with flocculent sludge. The reactor supplemented with magnetite was more stable and resilient than the no-magnetite control, with higher degree of granulation (up to 26.6-fold) and biomass retention. Magnetite addition to unstable reactors improved the methane yield in both reactors (1.2-1.3-fold). Electroactive Deltaproteobacteria bacteria, including Geobacter and Syntrophobacter, were enriched in the presence of magnetite. Methanogenic functional genes involved in DIET-based syntrophy were more abundant under magnetite-supplemented conditions. However, the improvement of methanogenic performance and granulation was limited, and inducing the self-embedment of magnetite into mature sludge granules rather than granulating flocculent sludge with magnetite appears to be a better strategy for engineering DIET in anaerobic granular sludge systems.
添加导电添加剂来促进直接种间电子转移（DIET）被认为是一种提高产甲烷菌的有前途的方法。本研究调查了添加亚微米磁铁矿颗粒对接种絮状污泥的上流式厌氧污泥床（UASB）反应器中污泥颗粒化和产甲烷性能的影响。补充磁铁矿的反应器比没有磁铁矿的对照反应器更稳定和有弹性，颗粒化程度更高（高达 26.6 倍）和生物量保留。向不稳定的反应器中添加磁铁矿提高了两个反应器中的甲烷产量（1.2-1.3 倍）。在磁铁矿存在的情况下，富集了电活性的 Delta 变形菌，包括 Geobacter 和 Syntrophobacter。在添加磁铁矿的条件下，参与 DIET 共生的产甲烷功能基因更为丰富。然而，产甲烷性能和颗粒化的改善是有限的，将磁铁矿诱导嵌入成熟的污泥颗粒中而不是用磁铁矿颗粒化絮状污泥，似乎是在厌氧颗粒污泥系统中进行 DIET 工程的更好策略。
