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Browsing BS by Author "Aima Zahid"

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    Characterization of oil degrading bacteria isolated from auto-mechanic workshop contaminated soil
    (UMT Lahore, 2022) Sher Ali; Aima Zahid; Uzma Zafar; Muskan Arooj
    Oil contamination poses a significant global environmental concern. Microorganisms capable of utilizing petroleum hydrocarbons for growth and metabolic activity are often enriched in oil-contaminated environments. In this study, bacteria were isolated from oil-contaminated soil collected near automobile service stations using Minimal Salt (MS) media. The growth of oil-utilizing bacteria was initially assessed using the spot test method, and their oil-degrading capacity was evaluated through gravimetric analysis and the emulsification index. Out of 16 bacterial isolates, five species—coded as ODB2, ODB5, ODB8, ODB9, and ODB15—were identified as oil-utilizing bacteria. Microscopy and biochemical tests, including catalase, oxidase, triple sugar iron, citrate, indole, coagulase, and MRVP, identified the isolates as Streptococcus spp. (ODB2 and ODB9), Bacillus sp. (ODB5), Serratia sp. (ODB8), and Pseudomonas sp. (ODB15). In biodegradation assays, Pseudomonas sp. exhibited the highest optical density (1.35) in minimal media, indicating its superior oil-degrading efficiency. Gravimetric analysis confirmed that Pseudomonas sp. had the highest potential for Mobil oil degradation, while Streptococcus sp. (ODB2) showed the lowest. Notably, Streptococcus sp. (ODB9) produced the maximum biomass (0.4 g) compared to the other isolates. Additionally, Serratia sp. and Pseudomonas sp. demonstrated the highest oil emulsification index of 50%. Future work will focus on molecular characterization of these oil-degrading species using 16S rRNA gene sequencing.