Phenanthrene Removal and Response of Complex Degradative Microbial Consortia

Microbial remediation has emerged as a promising strategy for removing polycyclic aromatic hydrocarbons (PAHs) from contaminated site soils; however, the availability of efficient microbial agents remains a critical constraint. Herein, this study isolated and constructed complex degradative microbial consortia from four typical sites. Using orthogonal experiments and high-throughput sequencing, it systematically investigated the degradation efficiency of phenanthrene (a representative PAH), alongside microbial diversity and microbial consortia structure, analyzed regulatory mechanisms via range analysis and variance analysis, and performed functional predictions by KEGG database. Results revealed that each of these microbial consortium individually achieved a 7-day average phenanthrene removal rate exceeding 82.66 %, and microbial consortia from different sources exhibited antagonistic or synergistic effects. Statistical analysis futher identified phenanthrene concentration and temperature as critical factors influencing degradation efficiency and microbial diversity. At the phylum level, the microbial consortia were dominated by Bacillota and Pseudomonadota: Bacillota dominated phenanthrene removal at higher temperatures, while Pseudomonadota was associated with removal at lower temperatures. At the genus level, they were dominated by Clostridium, No rank f. Symbiobacteraceae, and Neobacillus. Additionally, Metabolism was the primary enriched pathway. catA contributes more to degradation efficiency than catE, and temperature selectively regulated their abundance, thereby influencing the microbial consortia degradation efficiency. Overall, these findings highlight that such complex degradative microbial consortia offer a novel and robust bioremediation strategy for organic pollutant removal in harsh soil environments.