scholarly journals Degradation of poly aromatic fractions of crude oil and detection of catabolic genes in hydrocarbon-degrading bacteria isolated from Agbabu bitumen sediments in Ondo State

2019 ◽  
Vol 5 (4) ◽  
pp. 308-323 ◽  
Author(s):  
Temitayo O. Olowomofe ◽  
◽  
J. O. Oluyege ◽  
B.I. Aderiye ◽  
O. A. Oluwole ◽  
...  
2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Chioma Bertha Ehis-Eriakha ◽  
Chioma Blaise Chikere ◽  
Onyewuchi Akaranta

Crude oil pollution has consistently deteriorated all environmental compartments through the cycle of activities of the oil and gas industries. However, there is a growing need to identify microbes with catabolic potentials to degrade these pollutants. This research was conducted to identify bacteria with functional degradative genes. A crude oil-polluted soil sample was obtained from an aged spill site at Imo River, Ebubu, Komkom community, Nigeria. Bacteria isolates were obtained and screened for hydrocarbon degradation potential by turbidometry assay. Plasmid and chromosomal DNA of the potential degraders were further screened for the presence of selected catabolic genes (C230, Alma, Alkb, nahAC, and PAHRHD(GP)) and identified by molecular typing. Sixteen (16) out of the fifty (50) isolates obtained showed biodegradation activity in a liquid broth medium at varying levels. Bacillus cereus showed highest potential for this assay with an optical density of 2.450 @ 600 nm wavelength. Diverse catabolic genes resident in plasmids and chromosomes of the isolates and, in some cases, both plasmid and chromosomes of the same organism were observed. The C230 gene was resident in >50% of the microbial population tested, while other genes occurred in lower proportions with the least observed in nahAC and PAHRHD. These organisms can serve as potential bioremediation agents.


2021 ◽  
Vol 9 (6) ◽  
pp. 1200
Author(s):  
Gareth E. Thomas ◽  
Jan L. Brant ◽  
Pablo Campo ◽  
Dave R. Clark ◽  
Frederic Coulon ◽  
...  

This study evaluated the effects of three commercial dispersants (Finasol OSR 52, Slickgone NS, Superdispersant 25) and three biosurfactants (rhamnolipid, trehalolipid, sophorolipid) in crude-oil seawater microcosms. We analysed the crucial early bacterial response (1 and 3 days). In contrast, most analyses miss this key period and instead focus on later time points after oil and dispersant addition. By focusing on the early stage, we show that dispersants and biosurfactants, which reduce the interfacial surface tension of oil and water, significantly increase the abundance of hydrocarbon-degrading bacteria, and the rate of hydrocarbon biodegradation, within 24 h. A succession of obligate hydrocarbonoclastic bacteria (OHCB), driven by metabolite niche partitioning, is demonstrated. Importantly, this succession has revealed how the OHCB Oleispira, hitherto considered to be a psychrophile, can dominate in the early stages of oil-spill response (1 and 3 days), outcompeting all other OHCB, at the relatively high temperature of 16 °C. Additionally, we demonstrate how some dispersants or biosurfactants can select for specific bacterial genera, especially the biosurfactant rhamnolipid, which appears to provide an advantageous compatibility with Pseudomonas, a genus in which some species synthesize rhamnolipid in the presence of hydrocarbons.


2016 ◽  
Vol 78 (11-2) ◽  
Author(s):  
Nur Hafizah Azizan ◽  
Kasing Ak Apun ◽  
Lesley Maurice Bilung ◽  
Micky Vincent ◽  
Hairul Azman Roslan ◽  
...  

Enrichment culture technique leads to the discovery of six presumptive TPH-degrading bacteria. Identification and characterization tests using morphological, biochemical and molecular techniques have successfully isolated Pseudomonas aeruginosa (UMAS1PF), Serratia marcescens (UMAS2SF) and Klebsiella spp. (UMAS3KF). All strains were able to use crude oil as sole carbon and energy source for their growth since they were able to survive in Minimal Salt medium supplemented with 1% (v/v) crude oil. Growth study showed that they produced the highest cell counts on the third or fourth day by 108 – 1011 CFU/ml. Six artificial consortium inoculums have been produced from the growth study. Gas chromatography analysis showed that all isolates had the ability to degrade aliphatic hydrocarbon with 100% degradation of nC19 – C24. Among the isolates, UMAS2SF was the best and fastest n-alkane degrader with degradation percentage between 55 – 90% of n-C14 – C18 in 14 days. This was followed by UMAS1PF and UMAS3KF with 11 – 82% and 1.3% degradation, respectively. Enhancement study showed that plot with inoculum and NPK addition successfully enhanced n-alkane degradation. Plot A2:B3+NPK degraded n-alkane the fastest followed by plot treated by C+NPK, A1:B2, B+NPK and A2:B3. Result showed that UMAS1PF was the best PAHs degrader as most of the high molecular weight PAHs was degraded. In the enhancement study, the plot amended with A2:B3 showed the highest PAHs degradation, followed by plots A1:B2, A3:B1:C2 and A1:C3 that was assigned as the third, fourth and fifth best in mineralizing PAHs, respectively.


2018 ◽  
Vol 59 (2) ◽  
pp. 166-180
Author(s):  
Wael S. El-Sayed ◽  
Yasser Elbahloul ◽  
Mohamed E. Saad ◽  
Ahmed M. Hanafy ◽  
Abdelrahman H. Hegazi ◽  
...  

Author(s):  
Tudararo-Aherobo Laurelta ◽  
Okotie Sylvester ◽  
Ataikiru Tega ◽  
Stephen Avwerosuoghene

Aim: The research aims to assess the biodegradability of crude oil polluted aquatic environment using indigenous hydrocarbon degrading bacteria. Place and Duration of Study: The research was conducted in the Environmental Management and Toxicology Laboratory, Federal University of Petroleum Resources, Effurun, Delta State. Methodology: Hydrocarbon degrading bacteria species were isolated from hydrocarbon contaminated soils, screened and used for the degradation of crude oil. 5% and 10% crude oil were used to spike the test microcosm. Physicochemical parameters such as, pH, turbidity, total petroleum hydrocarbon (TPH) and bacterial counts of the bioremediated crude oil contaminated water were monitored on Day 0, 7 and 14. The biodegradation of the crude oil was done with the various bacteria isolates singly and as a consortium. Standard methods of American Public Health Association (APHA) and American Society for Testing and Materials (ASTM) were used for the analysis. Results: The isolates identified and used for the biodegradation process were, Azomonas sp., Enterococcus sp., Klebsiella sp. and Rhizobactersp. On day 14, in the microcosms with 5% crude oil contamination, Azomonas sp. recorded the highest turbidity reading of 328 ± 2.0 NTU, while Rhizobacter sp. recorded the least with 57.67 ± 0.58 NTU. The bacterial countswere between 7.68 ± 0.002 CFU/ml and 8.05 ± 0.10x 107 CFU/ml for Rhizobacter sp. and Azomonas sp. respectively.The crude oil was also degraded most in the microcosm treated with Azomonas sp. with a residual TPH concentration of 0.0013± 0.005 mg/l.For the 10% crude oil contaminated microcosms, TPH was also biodegraded most by Azomonas sp. with a value of 0.0026 ± 0.002mg/l. Turbidity readings were between 82 ± 1.0 NTU and 375.33 ± 0.57 NTU for Rhizobacter sp. and Azomonas sp. respectively. Bacterial counts were between (7.71± 0.012)x 107CFU/ml – (8.13± 0.001) x 107CFU/ml for Rhizobacter sp. and Azomonassp. respectively. Conclusion:There wasincreased microbial countsand decrease of residual crude oil concentration, indicating degradation of the crude oil by all the isolates.However, Azomonas sp. recorded the highest TPH degradation for both the 5% and 10% crude oil contaminated microcosms.Thus, findings from the research indicate that hydrocarbon degrading bacteria exist in our environment and can be used in the remediation of aquatic polluted environment.


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