Synthetic microbial communities enable sustainable restoration of coal gangue-impacted soils by reprogramming nutrient cycling

Coal gangue disrupts microbial diversity and impairs nutrient cycling, constraining sustainable regional development. Traditional bioremediation relies on functional microbial traits, yet they often fail to colonize and perform in carbon-limited environments despite exogenous carbon inputs. We designed activity-oriented synthetic microbial communities (SynComs) to leverage exogenous carbon amendments and subsequently evaluated carbon use efficiency (CUE) as a community-level functional trait. High-activity SynComs were assembled from native and non-native strains based on their activity and metabolite interactions. The native-derived SynCom (SC3) enhances carbon and nitrogen cycling, whereas the non-native-derived SynCom (SC5) boosts diversity and phosphorus cycling (P < 0.05). These contrasts were associated with differences in strain functional contributions, community interactions, and carbon-source utilization. Metabolomics revealed greater functional microbial activation in SC5-conditioned biochar-derived metabolites than in glucose-derived metabolites. Multi-omics, single-cell Raman spectroscopy, and field studies confirmed the positive roles of SynComs in rhizosphere metabolism and nutrient cycling. Activity-driven SynComs approach was more efficient than single amendments, offering a potentially scalable strategy to restore carbon-limited tailing ecosystems and promote sustainability.