Long-term starvation survival of a thermophilic sulfidogen consortium

A bacterial consortium containing thermophilic sulfidogens was obtained from filtration of produced fluids from a North Sea oil production facility. It was subjected to two distinct starvation regimes considered to be representative of those that might be experienced by such organisms surviving either (a) in open seawater prior to injection into the formation with secondary recovery fluids, or (b) in secondary recovery water-floods deep in the reservoir. Metabolic activity measurements and resuscitation data together with scanning electron microscopy indicate survival for 21 months with no available carbon source. Survival was measured by the starved cells' ability to reduce intracellularly the metabolic indicator INT to INT-formazan. By this method, starvation survival was demonstrated in all samples tested over the experimental period (up to 21 months). The indication of such ability was not consistently accompanied by resuscitation and growth in media previously used for culture maintenance and propagation.