Deciphering Ecological Mechanisms of Sulfidogen‐Methanogen Alliances in Acid Mine Drainage Treatment

ABSTRACT Acid mine drainage (AMD) remediation hinges on coordinated anaerobic metabolisms. The joint roles of sulfidogens and methanogens were investigated using groundwater‐, sludge‐ and sediment‐derived consortia in lactate‐fed batch reactors. Time‐resolved chemistry showed substantial metal removal with pH rising to about 6.5; sulphate declined by 78% to 91%, depending on inoculum. Microbial profiling, diversity indices, random forest and LEfSe identified Desulfobulbaceae , Desulfotomaculales and Methanobacteriaceae as keystone taxa. Ecological networks and structural equation modelling supported partial cooperation via shared substrates and electron flow, while also suggesting that increased methanogen abundance may be associated with reduced community complexity under certain conditions. KO‐based functional profiling indicated a sulphur‐anchored, reductant‐pooled organization in which sulphur‐cycling functions covaried positively with both guilds; reductant‐entry KOs and central‐carbon nodes increased together; nitrogen‐ and phosphorus‐linked functions scaled with overall metabolic throughput. These mechanisms underscore that harnessing both guilds enhances system adaptability and sustains pollutant transformation, with flexible sulphur acceptance anchoring electron flow and methanogens stabilizing the anaerobic regime.