Journal of Petroleum & Environmental Biotechnology

Abstract

Detection and Quantification of Sulfate-Reducing and Polycyclic Aromatic Hydrocarbon-Degrading Bacteria in Oilfield Using Functional Markers and Quantitative PCR

Nasser B, Ramadan AR, Hamzah RY, Mohamed ME and Ismail WA

Oilfield water samples from injection water treatment facility and soil/sludge samples from Gas Oil Separation Plant (GOSP) at Saudi Aramco were analyzed for the presence of SRB and PAH-degrading bacteria. SRB were detected by targeting a fragment of the apsA gene encoding adenosine-5-phosphosulfate reductase, which is characteristic of all SRB. The PAH-degrading bacteria were detected using a primer pair that amplifies a fragment of the gene encoding the large subunit of the naphthalene dioxygenase gene nahA. The nahA gene was detected in almost half of the soil/sludge samples with the highest copy number of 60540 copies/g soil/sludge. Most of the analyzed water samples contained high copy numbers of nahA gene with the highest copy number 3846 copies/ml. Most of the analyzed water samples revealed the presence of high copy numbers of the apsA gene with the highest copy number of 44 x 106/ml in sample number 2. Only 7 of the soil/sludge samples revealed the presence of the apsA gene with the highest copy number of 107920/g soil/sludge in sample number 11. In contrast to the nahA gene, the highest copy numbers of the apsA gene were detected in the water samples. SRB and PAH-degrading bacteria exist in some Saudi oilfields and appear to play a role in the H2S production and PAH degradation.