REVIEW ARTICLE published: 21 March 2011 doi: 10.3389/fmicb.2011.00044 The microbial sulfur cycle at extremely haloalkaline conditions of soda lakes Dimitry Y. Sorokin1,2*, J. Gijs Kuenen 2 and Gerard Muyzer 2 1 Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow, Russia 2 Department of Biotechnology, Delft University of Technology, Delft, Netherlands Edited by: Soda lakes represent a unique ecosystem with extremely high pH (up to 11) and salinity (up to Martin G. Klotz, University of Louisville, saturation) due to the presence of high concentrations of sodium carbonate in brines. Despite USA these double extreme conditions, most of the lakes are highly productive and contain a fully Reviewed by: Aharon Oren, The Hebrew University functional microbial system. The microbial sulfur cycle is among the most active in soda lakes. of Jerusalem, Israel One of the explanations for that is high-energy efficiency of dissimilatory conversions of inorganic Yanhe Ma, Institute of Microbiology sulfur compounds, both oxidative and reductive, sufficient to cope with costly life at double Chinese Academy of Sciences, China extreme conditions. The oxidative part of the sulfur cycle is driven by chemolithoautotrophic *Correspondence: haloalkaliphilic sulfur-oxidizing bacteria (SOB), which are unique for soda lakes. The haloalkaliphilic Dimitry Y. Sorokin, Winogradsky Institute of Microbiology, Russian SOB are present in the surface sediment layer of various soda lakes at high numbers of up to Academy of Sciences, Prospect 60-let 106 viable cells/cm3. The culturable forms are so far represented by four novel genera within the Octyabrya 7/2, 117312 Moscow, Russia Gammaproteobacteria, including the genera Thioalkalivibrio, Thioalkalimicrobium, Thioalkalispira, e-mail:
[email protected]; and Thioalkalibacter.