Aromatic Hydrocarbons Degradation and Plasmid Profile of Marine Bacterial Isolates Obtained from Petroleum Contaminated Marine Environments of Niger Delta Nigeria

Abstract

Aims: To determine the aromatic hydrocarbons degradability and plasmid profile of the marine bacteria isolated from Rivers State contaminated marine environments of Niger Delta. Study Design: Nine treatments and the controls designs were set up in triplicates containing 100 mL of sterile modified mineral basal medium in 500 mL conical flasks supplemented with 1 mg /L of xylene, anthracene and pyrene each; nine marine hydrocarbon degraders and incubated at 24 ºC for 24 days study. The nine treatments and control set ups designated as ANT1, XYL2, PYR3, ANT4, PYR5, ANT6, XYL7, XYL8, PYR9 and CTRL (Without hydrocarbons) were used to determine the aromatic hydrocarbons degradability and plasmid profile of the marine bacteria.   Place and Duration of Study: Department of Environmental Sciences, University of South Africa, Pretoria, South Africa between September, 2015 and March, 2018. Methodology: A laboratory scale study was carried on six composite samples of the sediment and water samples from the three studied areas using enrichment, screening, selection, morphological, biochemical, degradation and plasmid assays. Results: The findings revealed that the three sampling sites harbour a lot of efficient aromatic degrading bacterial strains belonging to the genera: Providencia, Alcaligenes, Brevundimonas, Myroides, Serratia, and Bacillus able to significantly (P = .05) tolerate and grow on the aromatic hydrocarbons. The bacterial strains especially Serratia marcescens XYL7 significantly (P = .05) removed 99.50 ± 0.05 % and 60.00 ± 0.02 % in weights of xylene and pyrene, respectively while Alcaligenes faecalis PYR5 significantly (P =.05) degraded 97.40 ± 0.01 % in weight of anthracene. The degradations of the respective hydrocarbons were found to be plasmid mediated with plasmid sizes between 200 bp - 1.2 kbp. Conclusion: Thus, the excellent degradative abilities of these bacterial strains especially Serratia marcescens XYL7 could be exploited for bioremediation purposes in Nigeria.