Facilitating anaerobic digestion of kitchen waste through diatomite-mediated spatial ecological niches construction

Anaerobic digestion (AD) presents an effective strategy for sustainable management of kitchen waste (KW), yet its widespread application remains constrained by suboptimal organic conversion efficiency and process instability. This study elucidates the critical role of diatomite (DE)-mediated spatial ecological niches construction in enhancing AD performance through microbial community regulation. Experimental results revealed that DE supplementation with optimal dosage of 10 g/L significantly improved methane production by 11.76 %, and maintained system stability through effective mitigation of volatile fatty acid accumulation and ammonia nitrogen inhibition. Further analysis demonstrated that DE served as an optimal surface for microbial attachment, enhancing biofilm formation and extracellular polymeric substance secretion, which in turn facilitated the selective enrichment and spatial organization of functional microbial communities. Microbial characterization showed that fermentative bacteria predominantly occupied the tightly-adsorbed community, while acetoclastic and hydrogenotrophic methanogens were enriched in the suspended community. Finally, the established ecological niches enhanced electron transfer and promoted syntrophic metabolism among methanogenesis-associated microorganisms. These findings provide mechanistic insights into material-mediated niche engineering strategies, establishing DE as an effective biofilm carrier for optimizing microbial resource utilization in AD systems.