Impact of Antibiotics Pretreatment on Bioelectrochemical CH4 Production
By Xu, Heng; Giwa, Abdulmoseen Segun; Wang, Cuiping; Chang, Fengmin; Yuan, Quan; Wang, Kaijun; Holmes, Dawn E.
Published in ACS Sustainable Chemistry & Engineering
Abstract
Methane (CH4)-producing bioelectrochemical systems (BES) are an attractive way to store excess renewable electricity and captured CO2. Studies have suggested that methanogenesis via direct electron uptake from a biocathode is more energetically efficient than hydrogenotrophic methanogenesis. However, mechanisms and key microorganisms involved in direct electron uptake remain unclear, primarily because of H2 produced by bacteria or extracellular hydrogenases in the system. In an attempt to minimize biological H2 production and enrich for methanogens that could efficiently convert electrons from the cathode surface to CH4, cathode chambers were pretreated with antibiotics targeting bacteria. We found that antibiotics pretreatment effectively reduced the proportion of H2-producing bacteria and H2-utilizing methanogens associated with the biocathode biofilm, and significantly promoted growth of acetoclastic methanogens from the genera Methanosarcina and Methanosaeta, several of which are known to participate in direct interspecies electron transfer. This shift in microbial community structure corresponded with 14%