Thermodynamic limits to microbial life at high salt concentrations
Article first published online: 5 NOV 2010
© 2010 Society for Applied Microbiology and Blackwell Publishing Ltd
Thematic Issue: Extremophiles. Guest Editors: Ricardo Cavicchioli, Ricardo Amils, Dirk Wagner, Terry McGenity
Volume 13, Issue 8, pages 1908–1923, August 2011
How to Cite
Oren, A. (2011), Thermodynamic limits to microbial life at high salt concentrations. Environmental Microbiology, 13: 1908–1923. doi: 10.1111/j.1462-2920.2010.02365.x
- Issue published online: 21 AUG 2011
- Article first published online: 5 NOV 2010
- Received 12 August, 2010; accepted 12 September, 2010.
Life at high salt concentrations is energetically expensive. The upper salt concentration limit at which different dissimilatory processes occur in nature appears to be determined to a large extent by bioenergetic constraints. The main factors that determine whether a certain type of microorganism can make a living at high salt are the amount of energy generated during its dissimilatory metabolism and the mode of osmotic adaptation used. I here review new data, both from field observations and from the characterization of cultures of new types of prokaryotes growing at high salt concentrations, to evaluate to what extent the theories formulated 12 years ago are still valid, need to be refined, or should be refuted on the basis of the novel information collected. Most data agree well with the earlier theories. Some new observations, however, are not easily explained: the properties of Natranaerobius and other haloalkaliphilic thermophilic fermentative anaerobes, growth of the sulfate-reducing Desulfosalsimonas propionicica with complete oxidation of propionate and Desulfovermiculus halophilus with complete oxidation of butyrate, growth of lactate-oxidizing sulfate reducers related to Desulfonatronovibrio at 346 g l−1 salts at pH 9.8, and occurrence of methane oxidation in the anaerobic layers of Big Soda Lake and Mono Lake.