Open AccessHaloalkaliphilic sulfur‐oxidizing bacteria in soda lakes
Author(s) -
Sorokin Dimitry Yu.,
Kuenen Johannes Gijs
Publication year - 2005
Publication title -
fems microbiology reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.91
H-Index - 212
eISSN - 1574-6976
pISSN - 0168-6445
DOI - 10.1016/j.femsre.2004.10.005
Subject(s) - biology , microaerophile , autotroph , gammaproteobacteria , bacteria , botany , denitrifying bacteria , extreme environment , ecology , denitrification , 16s ribosomal rna , chemistry , genetics , organic chemistry , nitrogen
The existence of chemolithoautotrophic sulfur‐oxidizing bacteria (SOB) capable of growth in an extremely alkaline and saline environment has not been recognized until recently. Extensive studies of saline, alkaline (soda) lakes located in Central Asia, Africa and North America have now revealed the presence, at relatively high numbers, of a new branch of obligately autotrophic SOB in these doubly extreme environments. Overall more than 100 strains were isolated in pure culture. All of them have the potential to grow optimally at around pH 10 in media strongly buffered with sodium carbonate/bicarbonate and cannot grow at pH < 7.5 and Na + concentration <0.2 M. The majority of the isolates fell into two distinct groups with differing phylogeny and physiology, that have been described as two new genera in the Gammaproteobacteria ; Thioalkalimicrobium and Thioalkalivibrio . The third genus, Thioalkalispira , contains a single obligate microaerophilic species T. microaerophila. The Thioalkalimicrobium group represents a typical opportunistic strategy, including highly specialized, relatively fast‐growing and low salt‐tolerant bacteria, dominating in hyposaline steppe soda lakes of Central Asia. The genus Thioalkalivibrio includes mostly slowly growing species better adapted to life in hypersaline conditions and with a more versatile metabolism. It includes denitrifying, thiocyanate‐utilizing and facultatively alkaliphilic species.