Synergistic remediation of phenanthrene cadmium contaminants by an immobilized acclimated bacterial and fungal consortium and its community response

Bioremediation has tremendous potential to mitigate the serious threats posed by polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs). In the present study, nine bacteriala nd fungal consortia were progressively acclimated under different culture conditions. Among them, a microbial consortium TM, originating from activated sludge and copper mine sludge microorganisms, was developed through the acclimation of a multi-substrate intermediate. TM exhibited the best PHE degradation, with an efficiency of 95.6% after7 d of inoculation, and its tolerance concentration for Cd2+ was up to 1800 mg/L within 48 h. Bacteria Pandoraea and Burkholderia, as well as fungi Ascomycota and Basidiomycota predominated in the TM consortium.Furthermore, immobilization led to more active consortium metabolic activity during the reaction, and the community structure developed in a more favorable direction. The dominant species were Proteobacteria, Bacteroidota, and Fusarium, and the predictive expression of functional genes corresponding to key enzymes was elevated. This study provides a basis for combining biochar and acclimated bacterial and fungal consortia for co-contaminated site remediation.