Unexpected diversity of heterotrophic prokaryotes living at the highest salt concentrations

Aharon Oren*

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


Halophilic Archaea (family Halobacteriaceae) were until recently the only heterotrophic microorganisms known to grow optimally at near-saturating salt concentrations. It now appears that Salinibacter ruber, an extremely halophilic bacterium related to the Flavobacterium-Cytophaga group, may occur in large numbers in saltern crystallizer ponds. The organism is red, and harbors a novel carotenoid pigment. There is a surprising similarity between the physiology of Salinibacter and the Halobacteriaceae. In both cases the cells contain molar concentrations of KCl, and organic compatible solutes contribute little to osmotic adaptation. The proteins of Salinibacter contain a large excess of acidic amino acids and are depleted in hydrophobic amino acids. Its cytoplasmic enzymes function at high salt. The discovery of Salinibacter and the elucidation of its properties show that similar modes of adaptation to life at high salt concentrations and low water activities may have evolved independently in phylogenetically distant groups.

Original languageAmerican English
Pages (from-to)201-204
Number of pages4
JournalEuropean Space Agency, (Special Publication) ESA SP
Issue number518
StatePublished - Sep 2002
EventProceedings of the Second European Workshop on Exo-Astrobiology - Graz, Austria
Duration: 16 Sep 200219 Sep 2002


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