Characterization of alkali-salt-tolerant diesel-degrading bacterial strain Pseudomonas aeruginosa BDL and its bioaugmentation for bioremediation of diesel-contaminated soil

Diesel contamination poses a significant threat to soil and public health. Microbial remediation, recognized for its eco-friendly benefits, necessitates the isolation of efficient diesel-degrading strains, particularly for saline-alkaline conditions. In this study, an alkali-salt-tolerant strain, Pseudomonas aeruginosa BDL, was isolated and demonstrated robust capabilities for degradation of diesel, crude oil, and petroleum hydrocarbons. Genomic analysis identified multiple hydrocarbon-degrading genes, including alkB , adhP , and ALDH , enabling its effective biodegradation of diesel pollutants. Strain BDL demonstrated moderate tolerance to saline-alkaline conditions, achieving a 72.02% removal of total petroleum hydrocarbons at pH 9, 20 g/L NaCl, and 0.5% (v/v) diesel. Bioaugmentation experiments revealed that P. aeruginosa BDL significantly enhanced diesel removal in soil. High-throughput sequencing indicated that diesel pollution reduced microbial diversity and richness. The abundance of Proteobacteria increased significantly under diesel stress, with Alcanivorax emerging as the predominant genus in both the bioaugmentation and control groups. Additionally, Pseudomonas successfully colonized the soil, contributing 5.69%–6.81% to the bioaugmented community. PICRUSt analysis suggested bioaugmentation enriched alkane-degrading genes, likely enhancing diesel biodegradation efficiency. This study highlights P. aeruginosa BDL as a promising microbial resource for bioremediation of petroleum-contaminated soils and offers practical insights for its application in environmental restoration.