Nitrogen Form-Dependent Shifts in Microbial Functional Pathways Explaining Biochar-Mediated Bioremediation of...

Area of Science:

• Environmental Science
• Soil Science
• Microbiology

Background:

• Petroleum contamination from agricultural activities poses risks to soil health and crop safety.
• Biochar derived from agricultural residues is a sustainable soil remediation option.
• Nitrogen availability often limits biochar's effectiveness in petroleum-contaminated soils.

Purpose of the Study:

• To investigate the impact of different nitrogen (N) sources on biochar-assisted petroleum soil remediation.
• To elucidate the mechanisms underlying enhanced degradation through multilevel analyses.
• To understand the interplay between nitrogen forms, microbial communities, and metabolic pathways.

Main Methods:

• Application of biochar with varied N sources (nitrate, ammonium, organic N) to petroleum-contaminated soil.
• Multilevel analyses including soil chemistry, enzyme assays, and 16S rRNA gene sequencing.
• Bioinformatic analyses using PICRUSt and KEGG for microbial functional prediction.

Main Results:

• Co-amendment with N fertilizers significantly enhanced petroleum removal (81.0-83.6%) compared to biochar alone (50.4%).
• Ammonium accelerated initial degradation, nitrate correlated with nitrogen-transforming microbes, and organic N supported long-chain alkane oxidation.
• Distinct microbial community shifts and predicted metabolic pathway changes were observed based on N form.

Conclusions:

• Nitrogen form critically influences the efficacy and mechanisms of biochar-based petroleum remediation.
• Understanding the coupled relationship between nitrogen, microbial function, and degradation pathways is key.
• This study provides a scientific foundation for optimizing nutrient strategies in soil remediation.