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

An anaerobic alkaliphilic, proteolytic bacterium, strain Su22 T , 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 T with a similarity of 98.1 %. Strain Su22 T differed from A. sibiricum Z-7981 T in its inability to use carbohydrates, peptone and amino acids as carbon sources. Strain Su22 T 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 T and Z-7981 T , 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 Т (=VKM B-2510 T =CECT 8731 T ).