LONG-TERM STARVATION SURVIVAL OF A THERMOPHILIC SULFIDOGEN CONSORTIUM

A bacterial consortium containing thermophilic sulfidogens was obtaine d from filtration of produced fluids from a North Sea oil production f acility. It was subjected to two distinct starvation regimes considere d to be representative of those that might be experienced by such orga nisms surviving either (a) in open seawater prior to injection into th e formation with secondary recovery fluids, or (b) in secondary recove ry water-floods deep in the reservoir. Metabolic activity measurements and resuscitation data together with scanning electron microscopy ind icate 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, starvatio n survival was demonstrated in all samples tested over the experimenta l period (up to 21 months). The indication of such ability was not con sistently accompanied by resuscitation and growth in media previously used for culture maintenance and propagation.