Phylogenetic Framework and Metabolic Genes Expression Analysis of Bacteria Isolated from Contaminated Marine Environments of Niger Delta

Abstract

Aims: To explore the phylogenetic framework of bacteria isolated from contaminated marine environments of Niger Delta and the expression of the metabolic genes coding for aromatic hydrocarbon degradation and surfactant production. Study Design: Nine treatments designs were set up in triplicates containing 25 mL of sterile modified mineral basal medium supplemented with nine marine hydrocarbon degraders incubated at 24°C for 5 days. Three of the set ups were supplemented each with 1 mg /L of xylene, anthracene and pyrene. Place and Duration of Study: Department of Environmental Sciences, University of South Africa, Pretoria, South Africa between September, 2015 to December, 2017. 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, characterization, and PCR assays to explore the phylogenetic framework and metabolic genes expression of the marine bacteria for aromatic hydrocarbon degradation and surfactant production. Results: The findings revealed that there was significant abundance of THB (P = .05) more than TCHUB and more xylene degraders than anthracene and pyrene degraders in the sediment and water samples respectively. The phylogenetic correlational analysis revealed that all the nine selected best degraders out of 48 isolates from the studied area were evolutionary related belonging to the genera: Providencia, Alcaligenes, Brevundimonas, Myroides, Serratia, and Bacillus; able to significantly (P = .05) utilize the all the aromatic hydrocarbons. The existence of catabolic and surfactant genes namely catechol dioxygenase (C23O), rhamnolipid enzyme (rhlB) and surfactin /lichenysin enzyme (SrfA3 /LicA3) genes were detected in only four (4) out of the nine (9) marine aromatic degrading bacteria  with 881 base pairs sizes. Conclusion: Thus, the study revealed that these bacterial strains especially Serratia marcescens XYL7 might possess metabolic genes for in situ aromatic hydrocarbon degradation and surfactant production.