AbstractThe effects of microbiologically influenced corrosion (MIC) can be very expensive to correct, dangerous to workers and its mechanisms are poorly understood. Understanding these processes is important so that they can be monitored and mitigated (Koch et al., 2001). It is now accepted that for the assessment of biocorrosion risks, the most powerful approach is to detect functional genes encoding the enzymes that play an important part in material deterioration (Schadt et al., 2004).
The main aim of this study was to identify the microbial community present in corroded and non-corroded systems, and to detect genes that might be implicated in corrosion processes, particularly iron corrosion, so that a biochip could be designed for risk assessment of oil environments. In this thesis the microbial populations and their actives were assessed using sequencing and hybridisation techniques for three oil field sites, generating information that can help identify MIC risk. The final section of the thesis describes the development and design of functional gene probes, identified from hybridisation studies that might be included in a biochip for risk assessment in oil field environments.
Microbial groups known to be involved in MIC, such as sulphate-reducing procaryota, iron-reducing bacteria, nitrate-reducing bacteria, hydrocarbon-degrading bacteria were detected, according to their 16S rRNA gene sequence, in the water injection system and production pipelines. In addition to these expected groups, sequences for Firmicutes, acetogens and methanogens were detected. Firmicutes, primarily Clostridium species, and Synergistetes sequences pre-dominated the corroded systems. Functional genes involved in biocorrosion, many of which belonged to the groups named above, were detected using the GeoChip, and a list of marker genes that can be utilised for biocorrosion monitoring has been proposed. Oligonucleotide probes for biochip development were either designed or selected from published sources. A quick and inexpensive method for probe evaluation during microarray development is described. A total of 16 probes, representing 15 genes were tested; all the probes exhibited similar hybridisation behaviour under standard conditions.
The results presented in this thesis were part of an extensive EU project, BIOCOR, involving academic and industrial partners, on fundamental and applied aspects of microbial corrosion in oil field environments, which was funded to generate the knowledge needed to develop monitoring techniques for corrosion. The results presented in this thesis are the final report to the European Commission.
|Date of Award||May 2014|
|Supervisor||Vitaly Zinkevich (Supervisor) & Iwona Beech (Supervisor)|