Deciphering the driving mechanism of microbial community for rapid stabilization and lignocellulose degradation during waste semi-aerobic bioreactor landfilling with multifunctional microbial inoculum

Abstract

Owing to the massive refractory lignocellulose and leachate-organic loads, the stabilization of municipal solid waste (MSW) landfill is often prolonged, resulting in environmental burdens. Herein, various assembled multifunctional microbial inoculums (MMIs) were introduced into the semi-aerobic bioreactor landfill (SABL) to investigate the bioaugmentation impacts. Compared to control (CK) and other MMIs treatments (G1-G3), LD + LT + DM inoculation (G4) significantly increased volatile solids degradation (9.72–45.03 %), while reducing chemical oxygen demand (COD) content (10.34–51.85 %) and ammonia nitrogen concentration (80.71–90.95 %) in the leachate. G4 also exhibited significantly higher degradation of cellulose and hemicellulose, achieving 0.99 and 1.94 times higher efficiency than CK, respectively. Microbial analysis revealed that LD + LT + DM reshaped microbial communities composition of SABL, with most of the introduced microorganisms (Enterobacter, Sphingobacterium, Streptomyces, etc.) successfully colonizing, and stimulating indigenous functional microbes associated with organic matter decomposition. Additionally, microbial interactions were strengthened in G4, accompanied by the higher abundance of 11 biomarkers and enzymes involved in lignocellulose degradation and ammonia nitrogen conversion. Overall, LD + LT + DM maximized MMI function by reconstructing synergistic core microbes. These findings highlight the superiority of LD + LT + DM in simultaneously regulating the microbial composition of lignocellulose-rich waste landfills, expediting MSW decomposition, improving leachate treatment, and mitigating odor emissions, offering valuable insights for efficient MSW management.