Petroleum hydrocarbons removal from the aged soil: Analysis of soil enzymes and microbial community evolution during phytoremediation of Suaeda salsa

ABSTRACT Rhizoremediation has emerged as a burgeoning approach for the removal of petroleum hydrocarbons (PHCs) from soil, with a primary emphasis on terrestrial plant systems. However, the mechanism on how soil microbiomes influence the dissipation of PHCs within a hygrophyte planting system has yet to be fully elucidated. This work concentrated on investigating the potential evolution of soil microbiomes and their effect on the PHCs dissipation within the Suaeda salsa (L.) Pall. planting system using the pot experiment. Two representative compounds, namely polycyclic aromatic hydrocarbons (PAHs) and n-alkanes, were used as target PHCs. The findings revealed a significant efficiency in the dissipation of petroleum hydrocarbons (PHCs) in soil, particularly with respect to n-alkanes. The high dissipation efficiency of PHCs was the synergistic result of both the root accumulation and the microbial biodegradation. The key microbes involved in PHCs dissipation were revealed, with the dominant phylum of Protobacteria and genus of Salinimicrobium . The alterations in microbial diversity and abundance were closely associated with the root exudation and PHCs exposure. Significant differences in enzyme activity, which serves as an indicator of soil health and fertility, were observed between the rhizospheric and non-rhizospheric soil, attributed to root exudation. This study offers novel insights into the phytoremediation potential for Suaeda in PHC-contaminated soil and serves as a valuable scientific reference for the phytoremediation of such soils.