- Title
- Bioremediation of oil from World War II (WWII) shipwrecks in the Pacific
- Creator
- Bainivalu, Awei Tiko
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2024
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- The shipwrecks from World War II (WWII) in the Pacific Ocean represent a potential source of oil pollution in the marine environment, with records indicating chronic oil leaks into the fragile lagoons and nearby marine ecosystems. Techniques currently used to remove oil from the sea surface and sunken wrecks have exorbitant costs and disrupt the marine environment through chemical treatments. The present study investigated the hydrocarbon fractions and the bacterial community associated with the historic fuel oil samples recovered from two WWII shipwrecks: Shinkoku Maru (SM) and Kiyosumi Maru (KM). The Total Petroleum Hydrocarbons (TPH), Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) and Poly Aromatic Hydrocarbons (PAH) were detected and quantified using Gas Chromatography – Flame Ionization Detector and Mass Spectrometry (GC-FID/GC-MS). Both the fuel oils from SM and KM exhibited high concentrations of TPH with short (F2), middle (F3) and long (F4) hydrocarbon chains. The TPH fractions were present in order of decreasing concentration: KM2 > SM1 > KM3. BTEX levels were higher in SM, and both fuel oil samples contained eight PAH compounds in high concentrations. The bacterial communities within the fuel oil samples, specifically Interphase (IP), Shinkoku Maru 1 (SM1), Kiyosumi Maru 2 (KM2) and Kiyosumi Maru 3 (KM3), were profiled targeting the V3/V4 region of the 16S rRNA gene. The analysis revealed a diverse microbial community comprising 42 Phyla, 107 Classes, 249 Orders, 432 Families, 1047 Genera and 1505 species. The dominant phyla in the fuel oil were Proteobacteria (77.9%), Actinobacteriota (35.7%), Firmicutes (19%) and Bacteroidota (6.1%). These findings underscore the presence of US EPA-prioritized pollutants in the fuel oil and highlight the bacterial diversity within the potential hydrocarbon-degrading community associated with historic fuel oil. Following the characterization of the hydrocarbon fractions and the bacterial community, a low-nutrient medium was developed for the enrichment and isolation of cultivable bacteria. A total of 42 marine bacteria were isolated and primarily screened for degradation profiles using a 2,6-DCPIP colourimetric assay. Twenty potential degraders were subjected to secondary screening based on their ability to utilize fuel oil as the sole carbon source. Eight hydrocarbon degraders belonging to Bacillus species within the Firmicutes phylum were identified through the amplification of the 16S rRNA gene. These eight isolates demonstrated the ability to degrade fuel oil, with degradation levels ranging from >20% to 48.6%. Once the degradation ability of the eight isolates was ascertained, the strains were grown in seawater. Based on the total protein concentration, the strains that exhibited high bacterial activity were selected for the microcosm bioremediation study. Individual degradation efficiencies of strains S1 and S4, as well as their consortium S1+S4, were evaluated. S1 and S4 belonged to the Bacillus genus, specifically B. proteolyticus and B. cereus, respectively. Strain S4 exhibited a high degradation rate of SM oil at 62.2%, the consortium achieved a degradation rate of 57%, and S1 exhibited a rate of 54.4%. Notably, the consortium proved more effective in degrading heavy hydrocarbon fractions, especially in heavy fuel oil. These results demonstrate the intrinsic bioremediation ability of strains isolated from fuel oil. Moreover, it accentuates the significant potential of native hydrocarbon-degrading bacteria obtained from historic fuel oil sources as a means to develop bioremediation technology to mitigate oil spills from WWII shipwrecks in the Pacific.
- Subject
- WWII shipwrecks; historic fuel oil; bacterial community profiling; petroleum hydrocarbon degradation; bioremediation technology; environmental remediation; hydrocarbon degrading-bacteria; total petroleum hydrocarbon (TPH); Pacific Ocean; oil pollution
- Identifier
- http://hdl.handle.net/1959.13/1511422
- Identifier
- uon:56492
- Rights
- This thesis is currently under embargo and will be available from 13.03.2025. Copyright 2024 Awei Tiko Bainivalu
- Language
- eng
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