Molecular Profiling of Hydrocarbon Degrading Microbial Communities of Petroleum Contaminated Soil in Noakhali Region, Bangladesh
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Date
2025-12-15
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Abstract
Petroleum hydrocarbon contamination represents a persistent environmental challenge due to its
ecological toxicity and long-term impacts on soil health and microbial communities. Despite
increasing vulnerability to petroleum pollution in Bangladesh, particularly in coastal and transport-
linked regions, the microbial ecology of contaminated soils in Noakhali remains poorly
understood. This study investigated the diversity, functional potential, and antimicrobial resistance
profiles of indigenous microbial communities inhabiting petroleum-contaminated soils from
selected filling stations in Noakhali, Bangladesh, using an integrated culture-dependent and 16S
rRNA gene-based metagenomics approach.
Selective enrichment using Mineral Salt Medium supplemented with diesel resulted in the isolation
of 33 potential hydrocarbon-degrading bacterial strains. Morphological, Gram-staining, and
biochemical characterization identified Pseudomonas spp. as the dominant genus, including
Pseudomonas aeruginosa, alongside Klebsiella, Acinetobacter, Enterobacter, Hafnia, Bacillus,
Staphylococcus, Micrococcus, and Streptococcus species. Functional screening revealed strong
lipase and biosurfactant production by Pseudomonas aeruginosa. Antimicrobial susceptibility
testing demonstrated site-specific resistance patterns, with the highest resistance observed at
Sonapur Filling Station, suggesting localized anthropogenic pressure.
High-throughput sequencing of the 16S rRNA gene identified 172 unique Amplicon Sequence
Variants (ASVs). Alpha diversity analyses revealed the highest microbial richness at Alexander
Filling Station (AFS). Taxonomic analysis revealed that the microbial communities were
predominantly composed of Bacteroidota and Proteobacteria, with notable representation of
hydrocarbon-degrading lineages such as Pseudomonas, Rhodococcus, and Acinetobacter, while
Prevotella and Pseudomonas emerged as the most abundant genera. Predicted functional profiling
indicated enrichment of key metabolic pathways and genes involved in alkane and aromatic
hydrocarbon degradation, nitrogen and sulfur cycling, and antibiotic resistance, with AFS
exhibiting the highest hydrocarbon-degrading potential.
This study provides the first comprehensive molecular insight into petroleum-contaminated soils
of Noakhali and underscores the ecological significance of indigenous microbial communities for
site-specific, sustainable bioremediation strategies in Bangladesh.