Methanogenesis Disruption by Sulfoxaflor in Microbial Aggregation Mediated by Inhibition on Energy Metabolism

Neonicotinoid contamination of surface water has drawn global attention due to its influence on ecosystems. However, there has been no directional fundamental study of their impact on biological methanogenesis. In this study, we evaluated the removal of neonicotinoid sulfoxaflor in anaerobic reactors by anaerobic granular sludge (AGS) and found that adsorption is the main removal mechanism. Sulfoxaflor was adsorbed onto AGS and changed the surface properties of the extracellular polymeric substances. Short-term sulfoxaflor exposure inhibited methane production of AGS. In detail, typical acetogenic bacteria and methanogens were selected to reveal the underlying molecular responses and metabolic pathways involved in biological methanogenesis. Sulfoxaflor reduced the acetic acid production of acetogenic bacteria and methane production of methanogenic archaea. Transcriptomics results demonstrated that sulfoxaflor disturbed adenosine triphosphate synthesis and metabolic profiling during biological methanogenesis. Overall, this study clarified the mechanism by which sulfoxaflor inhibits methanogenesis during microbial aggregation.