Accelerating Anaerobic Oxidation of Methane Coupled with Extracellular Electron Transfer to Electrodes Via Magnetite Stimulating Membrane-Bound Proteins of Anaerobic Methanotrophic (Anme) Archaea/Methanogens

作     者：Liang, Lianfu Wang, Mingwei Yu, Qilin Zhao, Zhiqiang Zhang, Yaobin 

作者机构： Ministry of Education School of Environmental Science and Technology Dalian University of Technology Dalian116024 China State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing100084 China 

出 版 物：《SSRN》 

年 卷 期：2023年

核心收录：

主　　题：Electrodes 

摘      要：Methane-dependent bioelectrochemcial systems (BESs) have been recently considered as a promising approach for mitigating methane emission, energy harvesting as well as water environmental remediation. However, the mechanisms of extracellular electron transfer (EET) from anaerobic methanotrophic (ANME) archaea/methanogens to electrodes are still unclear. The study presented here showed that, anodic biofilms amended with magnetite primarily comprised of ANME archaea/methanogens were electrically conductive, determined with a conducting-probe atomic force microscope. Scanning electrochemical microscopy and electrochemical Fourier transform infrared spectra found that, anodic biofilms were redox-based electrically active, with a high concentration of redox-active proteins displayed on their surface. Metagenomics also detected some electroactive bacteria (Ignavibacterium and Geobacter species), the abundance of which however declined with magnetite. In addition, the difference in the abundance of genes encoding the cytochrome c (CYC)-like proteins with or without magnetite was not evident, and the abundance of genes encoding the type IV pilus assembly proteins declined with magnetite. Remarkably, magnetite specially increased the abundance of genes encoding the membrane-bound proteins, Rnf, and periplasmic heterodisulfide reductase, HdrABC, in ANME archaea/methanogens, providing a possibility that magnetite sped up methane oxidation as well as electron transfer from inner membrane to outer membrane in anaerobic oxidation of methane (AOM) coupled with EET to electrodes. As a result, the current density in the magnetite-supplemented BES was increased by approximately 6-9 folds. © 2023, The Authors. All rights reserved.