Our team will focus on developing an eco-friendly approach to limit the use of biocides in the oil-production industry. A wide range of bacterial species are found in the areas near oil extraction facilities. Many of these organisms cause serious problems for the oil industry by producing corrosive by-products. Sulfate-reducing bacteria (SRB), the main species involved in the Microbial Induced Corrosion (MIC), can colonize on the pipelines by forming bacterial biofilms with the release of Extracellular Matrix Substances (EMS) for adhesion and colony growth. Currently, biocides are commonly used in the oil industry for targeting these bacteria. But, these chemicals ultimately end up in the sea water which poses a huge threat to marine life.
Bacteria can sense a vast range of environmental signals, from the concentrations of nutrients and toxins to oxygen levels, pH and osmolarity. For our project, we plan to genetically engineer both sensor and remediation bacteria to sense osmolarity of the water used for "Water sweeping", which allows extraction of maximum volume of crude oil, and then to secrete an enzyme to degrade the extracellular matrix of the biofilm.
Halanaerobium which is the major SRB found in these pipelines live on high salt concentrations (optimally at NaCl concentrations 1.7–2.5 M and requiring a minimum of 0.3–1.7 M NaCl for growth). Therefore, we plan to use water samples obtained from an oil extraction company in Qatar to determine the exact concentrations required for optimal growth of the SRB’s. We will construct a salt biosensor using the osmo-responsive promoter of the ProU operon to drive a Red Fluorescent Protein (RFP) expression, which can be measured using fluorescence and a plate reader. This will allow us to monitor the osmolarity of outflow to determine if the SRB are likely to grow. After osmolarity biosensor is added, samples from the water can be taken frequently and the RFP’s fluorescence can be measured using simple fluorescence measurement in a plate reader.
If a high concentration of salt is measured, then we can then use the strain expressing Dispersin B (DspB) gene, which codes for a protein that digests the polysaccharides, a major component of the biofilms. As the action of Dispersin B will expose the bacterial population to the outside environment, therefore, the use of biocides will be more effective. Hence, by regulating the frequency of adding biocides, as well as by making the functioning of existing biocides more efficient, we plan to decrease the over all use of chemical biocides.