title: Enhanced methane production in an anaerobic digestion and microbial electrolysis cell coupled system with co-cultivation of Geobacter and Methanosarcina.
abstract: The anaerobic digestion (AD) and microbial electrolysis cell (MEC) coupled system has been proved to be a promising process for biomethane production. In this paper, it was found that by co-cultivating Geobacter with Methanosarcina in an AD-MEC coupled system, methane yield was further increased by 24.1%, achieving to 360.2 mL/g-COD, which was comparable to the theoretical methane yield of an anaerobic digester. With the presence of Geobacter, the maximum chemical oxygen demand (COD) removal rate (216.8 mg COD/(L·hr)) and current density (304.3A/m(3)) were both increased by 1.3 and 1.8 fold compared to the previous study without Geobacter, resulting in overall energy efficiency reaching up to 74.6%. Community analysis demonstrated that Geobacter and Methanosarcina could coexist together in the biofilm, and the electrochemical activities of both were confirmed by cyclic voltammetry. Our study observed that the carbon dioxide content in total gas generated from the AD reactor with Geobacter was only half of that generated from the same reactor without Geobacter, suggesting that Methanosarcina may obtain the electron transferred from Geobacter for the reduction of carbon dioxide to methane. Taken together, Geobacter not only can improve the performance of the MEC system, but also can enhance methane production.
authors.affiliation: Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu 610041, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Yin
authors.affiliation: Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu 610041, China. Electronic address: zhuxy@cib.ac.cn.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu 610041, China.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Zhan
authors.affiliation: Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu 610041, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Bo
authors.affiliation: Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu 610041, China.
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu 610041, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Tao
authors.affiliation: Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu 610041, China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: He
authors.affiliation: Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu 610041, China. Electronic address: lidp@cib.ac.cn.
authors.forename: Daping
authors.initials: D
authors.lastname: Li
authors.affiliation: Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu 610041, China.
authors.forename: Zhiying
authors.initials: Z
authors.lastname: Yan
mesh_terms: D000693:Anaerobiosis; D001674:Bioelectric Energy Sources; D057919:Biological Oxygen Demand Analysis; D002245:Carbon Dioxide; D004572:Electrolysis; D045302:Geobacter / Q000502:physiology*; D008697:Methane / Q000378:metabolism*; D017020:Methanosarcina / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide; D008697:Methane
keywords: AD–MEC coupled system; Co-cultivation; Geobacter; Methane production; Methanosarcina