Masters Thesis

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Browsing Masters Thesis by Author "ASH2305MS106M"

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    Molecular Profiling of Hydrocarbon Degrading Microbial Communities of Petroleum Contaminated Soil in Noakhali Region, Bangladesh
    (2025-12-15) ASH2305MS106M
    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.