Metagenomic and Physicochemical Characterization of Diesel Contaminated Soil from University of Calabar Power Plant: In-Sights to Bacterial Diversity and Community Function

Petroleum-contaminated soils provide an ideal environment for hydrocarbon-degrading bacteria, necessitating the study of their microbial ecology and community changes. This research compared diesel-impacted power plant soil (PPS) from the University of Calabar with pristine soil (CSS) as a control, the samples (50 g) were randomly collected from depths of 0-15 cm, 15-30 cm, and 30-45 cm. Physicochemical and metagenomic analyses were conducted. Taxonomic profiling with functional gene analyses via COG and PRK frameworks performed. PPS displayed higher concentrations of organic carbon (7.02%), total petroleum hydrocarbons (8500 mg/kg), nitrogen (0.51%), phosphorus (3.65 g/kg), lead (175 mg/kg), iron (2619 mg/kg), and copper (196.55 mg/kg) than CSS. Conversely, CSS had higher pH, temperature, conductivity, and moisture content. Bacterial abundance was slightly higher in CSS (89.24%) than in PPS (87.47%), with distinct dominant microbial taxa between samples. Functional analysis identified COG Class I (lipid transport and metabolism) as the most abundant in PPS (32.37%), linked to the predominant hydrocarbon-degrading bacterium Bacillus amyloliquefaciens (26.24%), absent in CSS. In contrast, CSS had COG Class O (posttranslational modification) as the highest (94%). These results demonstrate that petroleum pollution promotes the growth of hydrocarbon-degrading bacteria, underscoring the ecological impacts of contamination on soil microbial communities.