Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China.
Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-environmental & Technology, Guangzhou, 510650, China.
Microb Biotechnol. 2018 Jul;11(4):710-720. doi: 10.1111/1751-7915.13286. Epub 2018 Jun 12.
Ammonia accumulation is a major inhibitory substance causing anaerobic digestion upset and failure in CH production. At high ammonia levels, CH production through syntrophic acetate oxidization (SAO) pathways is more tolerant to ammonia toxicity than the acetoclastic methanogenesis pathway, but the low CH production rate through SAO constitutes the main reason for the low efficiency of energy recovery in anaerobic digesters treating ammonia-rich substrates. In this study, we showed that acetate fermentation to CH and CO occurred through SAO pathway in the anaerobic reactors containing a high ammonia concentration (5.0 g l NH -N), and the magnetite nanoparticles supplementation increased the CH production rates from acetate by 36-58%, compared with the anaerobic reactors without magnetite under the same ammonia level. The mechanism of facilitated methanogenesis was proposed to be the establishment of direct interspecies electron transfer (DIET) for SAO, in which magnetite facilitated DIET between syntrophic acetate oxidizing bacteria and methanogens. High-throughput 16S rRNA gene sequencing analysis revealed that the bacterial Geobacteraceae and the archaeal Methanosarcinaceae and Methanobacteriaceae might be involved in magnetite-mediated DIET for SAO and CH production. This study demonstrated that magnetite supplementation might provide an effective approach to accelerate CH production rates in the anaerobic reactors treating wastewater containing high ammonia.
氨积累是一种主要的抑制物质，会导致厌氧消化失调和 CH 生产失败。在高氨水平下，通过共代谢乙酸氧化（SAO）途径的 CH 生产对氨毒性的耐受性高于乙酸同化甲烷生成途径，但通过 SAO 的低 CH 生产速率构成了在处理富含氨的基质的厌氧消化器中能量回收效率低的主要原因。在这项研究中，我们表明，在含有高氨浓度（5.0 g l NH-N）的厌氧反应器中，乙酸通过 SAO 途径发酵为 CH 和 CO，并且与相同氨水平下没有磁铁矿的厌氧反应器相比，磁铁矿纳米颗粒的添加将乙酸的 CH 生产速率提高了 36-58%。促进甲烷生成的机制被提出为 SAO 的直接种间电子转移（DIET）的建立，其中磁铁矿促进了共代谢乙酸氧化细菌和产甲烷菌之间的 DIET。高通量 16S rRNA 基因测序分析表明，细菌 Geobacteraceae 和古菌 Methanosarcinaceae 和 Methanobacteriaceae 可能参与了磁铁矿介导的 SAO 和 CH 生产中的 DIET。本研究表明，磁铁矿的添加可能为加速处理富含氨的废水的厌氧反应器中的 CH 生产速率提供一种有效方法。
