Original Investigation of the Chemistry of Biofilm Formation on Oil and Gas Pipeline Surfaces and Development of Novel Biocide Formulations

Microbiologically influenced corrosion caused by sulphate-reducing bacteria and other biofilm-forming microorganisms is responsible for a significant proportion of pipeline failures in the Nigerian oil and gas sector, causing economic losses estimated in billions of dollars annually and contributing to environmental contamination. The biochemistry of biofilm formation on steel pipeline surfaces and the molecular mechanisms of biocide resistance in Nigerian petroleum biofilm communities are incompletely characterised. This study conducted an original investigation of the chemistry of biofilm formation on pipeline steel surfaces under simulated in-situ conditions and developed novel multi-component biocide formulations targeting the identified molecular vulnerabilities. Biofilm samples were collected from production facility piping in Bayelsa State and characterised by 16S rRNA gene amplicon sequencing for microbial community profiling, metabolomics for extracellular polymeric substance chemical characterisation, and confocal laser scanning microscopy for biofilm structural analysis. Sulphate-reducing bacteria, iron-reducing bacteria, and nitrate-reducing bacteria were identified as the dominant biofilm community members. Extracellular polymeric substance composition was analysed by Fourier-transform infrared spectroscopy and gas chromatography-mass spectrometry, revealing polysaccharides, proteins, and extracellular DNA as major structural components. Minimum biofilm eradication concentrations were determined for eight commercial biocides, revealing significant tolerance in established biofilms compared to planktonic cells. Three novel biocide formulations based on quaternary ammonium-terpene combinations and biocide-chelator combinations were synthesised and evaluated. Optimal formulations achieved 99.97 percent biofilm eradication at concentrations 40 percent below effective doses for single-component commercial biocides. This original research provides a chemistry-informed foundation for improved microbiologically influenced corrosion control in Nigerian petroleum infrastructure.

Keywords: biofilm chemistry, microbiologically influenced corrosion, pipeline corrosion, biocide development, oil and gas