Evaluation of electromethanogenesis in a microbial electrolysis cell using nylon cloth as a separator: Reactor performance and metagenomic analysis.

This study aimed to propose a novel approach for simultaneous CO 2 abatement and energy storage in microbial electrolysis cells (MECs). The methane (CH 4) production from CO 2 was achieved in a graphite granule–filled cathodic compartment of an MEC separated by a modified nylon cloth. Using the modified nylon cloth in MEC significantly reduced membrane internal resistance compared with the control where a commercial proton exchange membrane (PEM) was used (PEM: 1746 ± 80 TΩ/cm; nylon cloth: 251 ± 8 TΩ/cm). Consequently, CH 4 production realized 72.9 ± 24.4 mL/(L ∙ d) with an average energy efficiency of 121 ± 39% compared with halted electromethanogenesis in PEM-equipped MEC. Metagenomics affirmed the predominance of hydrogenotrophic methanogens Methanocorpusculum and Methanobacterium. Moreover, H 2 -mediated methanogenesis contributed significantly to electromethanogenesis in nylon-MEC. This study demonstrated that the bioelectrochemical conversion of CO 2 into CH 4 in a nylon-MEC could be viable for CO 2 sequestration combined with energy storage (power to gas). • Microbial electrolysis cells (MECs) with different separators were used for CH 4 yield. • Modified nylon cloth surpassed proton exchange membrane in electromethanogenesis. • Nylon cloth-equipped MECs obtained prominent energy efficiency. • Hydrogenotrophic Methanocorpusculum and Methanobacterium were dominant methanogens. • H 2 -mediated methanogenesis contributed significantly to electromethanogenesis. [ABSTRACT FROM AUTHOR]