Enrichment and characterisation of sulfate-reducing bacteria from sandstone rock cores from the UK Continental shelf

Abstract

A fresh sandstone core was extracted during drilling of an exploration well within a United Kingdom Continental Shelf oilfield at a depth of approximately 1000 m. Scanning electron microscopy of the rock core revealed cell-like structures attached to the sandstone grains. Microbiological analysis demonstrated that the inner core was not sterile but contained sulfate-reducing bacteria and other anaerobes. One enrichment culture of sulfate-reducing bacteria (denoted EX306), was chosen for further study. Enrichments of EX306 showed that it was comprised of a tightly knit group of three different bacteria which continued as a stable community despite repeated subculturing for over 2 years. EX306 was able to utilise pyruvate-producing acetate and propionate as metabolites, growth was optimal at 55°C.