Biodegradation of PAEs in contaminated soil by immobilized bacterial agent and the response of indigenous bacterial community

Phthalic acid esters (PAEs) are common hazardous organic contaminants in agricultural soil. Microbial remediation is an effective and eco-friendly method for eliminating PAEs. Nevertheless, the operational mode and potential application of immobilized microorganisms in PAEs-contaminated soil are poorly understood. In this study, we prepared an immobilized bacterial agent (IBA) using a cedar biochar carrier to investigate the removal efficiency of PAEs by IBA in the soil. We found that IBA degraded 88.35% of six optimal-control PAEs, with 99.62% biodegradation of low-molecular-weight PAEs (DMP, DEP, and DBP). The findings demonstrated that the IBA achieved high efficiency and a broad-spectrum in degrading PAEs. High-throughput sequencing revealed that IBA application altered the composition of the soil bacterial community, leading to an increase in the relative abundance of PAEs-degrading bacteria (Rhodococcus). Furthermore, co-occurrence network analysis indicated that IBA promoted microbial interactions within the soil community. This study introduces an efficient method for the sustainable remediation of PAEs-contaminated soil.