Anoxynatronum buryatiense sp. nov., an anaerobic alkaliphilic bacterium from a low mineralization soda lake in Buryatia, Russia.

An anaerobic alkaliphilic, proteolytic bacterium, strain Su22, was isolated from the bottom sediment of the alkaline low mineralization lake Sulphatnoe (Selenginsky district, Buryatia, Russia). A comparative analysis of the 16S rRNA gene sequence revealed that this bacterium was closely related to Anoxynatronum sibiricum Z-7981 with a similarity of 98.1 %. Strain Su22 differed from A. sibiricum Z-7981 in its inability to use carbohydrates, peptone and amino acids as carbon sources. Strain Su22 grew over a temperature range of 20-40 °C with an optimum at 30 °C and within the pH range 7.4-11.0 with an optimum at pH 9.6. Sodium cations stimulated the growth of the strain considerably with an optimal concentration at 0.76-1.09 M. The whole-cell fatty acid profile included C16 : 1ω7c, C16 : 0 and C16 : 0 ALDE. The G+C content was 46.1 mol%. Based on the DNA-DNA hybridization level (53.2 %) and phenotypical differences between strains Su22 and Z-7981, the new isolate is thus considered to represent a novel species, for which the name Anoxynatronumburyatiense sp. nov. is proposed. The type strain is Su22 (=VKM B-2510=CECT 8731).