Sulphate-Reducing Bacteria in Crude Oil and Procuded Water: Cell Quantification and apsA Gene Expression

Abstract

The quantification of planktonic sulphate-reducing bacteria (SRB) in crude oil and produced water and their adenosine-5’-phosphosulphate reductase alpha subunit (apsA) gene expression were carried out using real-time polymerase chain reaction (PCR). Real-time PCR is considered a highly sensitive method for the quantification of microbial organisms and gene expression in environmental samples. This study was conducted to evaluate real-time PCR with SYBR Green detection as a quantification method for SRB and its apsA gene expression in crude oil and produced water. Standard curves were developed for both quantifications. The results showed that sample A (crude oil) had lesser SRB concentration (2.86 μg/ml) and apsA gene expression with Cycle threshold (Ct) value: 7.48than sample B (produced water) with SRB concentration of 1.27x106μg/ml and Ct-value: 6.77. The lower Ct-value of sample B showed more gene expression than sample A. This implied that sample B may have been contaminated by subterranean water.