Culture dependent methods for enumeration of sulphate reducing bacteria (SRB) in the Oil and Gas industry

The group of anaerobic microorganisms collectively referred to as Sulphate Reducing Bacteria (SRB) is a major concern in the Oil and Gas industry primarily because of this group's ability to generate substantial amounts of hydrogen sulfide and insoluble ferrous sulfide in the presence of iron. Traditionally, the Oil industry has relied on two recommended standard practices i.e. API RP-38 and NACE TM0194 for the detection and enumeration of culturable sulphate reducing bacteria for routine field monitoring. API RP-38 has now been withdrawn without any replacement. Data generated by nonstandard molecular microbiological methods which are still in the developmental stage cannot be compared with the accepted control levels for SRBs in oil field systems, monitored over the years with viable culture methods. Culture based methodologies are still important tools for the study of SRB, as they help in understanding the physiological characteristics which may be similar or different across phylogenetically similar bacteria. This review article therefore tries to highlight the continued importance of culture dependent methods for detection and enumeration of SRB in Oil field systems and the need for further development of an universal standard culture based method for studying SRB in the Oil and Gas industry.