Electro-conversion of carbon dioxide (CO) to low-carbon methane by bioelectromethanogenesis process in microbial electrolysis cells: The current status and future perspective.

Given the aggravated greenhouse effect caused by CO and the current energy shortage, CO capture and reuse has been gaining ever-increasing concerns. Microbial Electrolysis Cells (MECs) has been considered to be a promising alternative to recycle CO bioelectrochemically to low-carbon electrofuels such as CH by combining electroactive microorganisms with electrochemical stimulation, enabling both CO fixation and energy recovery. In spite of the numerous efforts dedicated in this field in recent years, there are still many problems that hinder CO bioelectroconversion technique from the scaling-up and potential industrialization. This review comprehensively summarized the working principles, extracellular electron transfers behaviors, and the critical factors limiting the wide-spread utilization of CO electromethanogenesis. Various characterization and electrochemical testing methods for helping to uncover the underlying mechanisms in CO electromethanogenesis have been introduced. In addition, future research needs for pushing forward the development of MECs technology in real-world CO fixation and recycling were elaborated.