NanoFe3O4 as Solid Electron Shuttles to Accelerate Acetotrophic Methanogenesis by Methanosarcina barkeri
NanoFe3O4 as Solid Electron Shuttles to Accelerate Acetotrophic Methanogenesis by Methanosarcina barkeri
复制标题
NanoFe(3)O(4)作为固体电子梭加速巴克甲烷八叠球菌的醋营养产甲烷作用
DOI：
10.3389/fmicb.2019.00388
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发表时间：
2019-03-05
影响因子：
5.2
通讯作者：
Zhou, Shungui
中科院分区：
文献类型：
--
作者：
Fu, Li;Zhou, Ting;Zhou, Shungui
据报道，磁铁矿纳米颗粒(nanoFe（3)O(4)）可以促进合成气细菌和产甲烷菌之间的直接种间电子转移（DIET），从而改善合成气产甲烷。然而，纳米ofe (3)O(4)是否或如何影响乙营养化甲烷生成仍然未知。在本研究中，我们证明了纳米ofe (3)O(4)在促进富甲烷菌直接醋酸营养化产甲烷中的独特作用，并通过barkeri甲烷菌的纯培养进一步证实了这一点。与其他电导率较高的纳米材料如碳纳米管和石墨相比，混合价Fe（II）和Fe（III）的纳米ofe (3)O(4)对甲烷生成的刺激作用最为显著，表明其氧化还原活性而非电导率促进了barkeri的甲烷生成。细胞形态学和光谱学分析表明，纳米ofe (3)O(4)渗透到巴氏分枝杆菌的细胞膜和细胞质中。这些结果提供了一种前所未有的可能性，即产甲烷菌细胞膜中的纳米ofe (3)O(4)作为电子穿梭体，促进细胞内电子转移，从而提高甲烷产量。这项工作不仅对理解矿物-产甲烷菌相互作用的机制，而且对优化工程产甲烷过程具有重要意义。
Magnetite nanoparticles (nanoFe(3)O(4)) have been reported to facilitate direct interspecies electron transfer (DIET) between syntrophic bacteria and methanogens thereby improving syntrophic methanogenesis. However, whether or how nanoFe(3)O(4) affects acetotrophic methanogenesis remain unknown. Herein, we demonstrate the unique role of nanoFe(3)O(4) in accelerating methane production from direct acetotrophic methanogenesis in Methanosarcina-enriched cultures, which was further confirmed by pure cultures of Methanosarcina barkeri. Compared with other nanomaterials of higher electrical conductivity such as carbon nanotubes and graphite, nanoFe(3)O(4) with mixed valence Fe(II) and Fe(III) had the most significant stimulatory effect on methane production, suggesting its redox activity rather than electrical conductivity led to enhanced methanogenesis by M. barkeri. Cell morphology and spectroscopy analysis revealed that nanoFe(3)O(4) penetrated into the cell membrane and cytoplasm of M. barkeri. These results provide the unprecedented possibility that nanoFe(3)O(4) in the cell membrane of methanogens serve as electron shuttles to facilitate intracellular electron transfer and thus enhance methane production. This work has important implications not only for understanding the mechanisms of mineral-methanogen interaction but also for optimizing engineered methanogenic processes.