gen. nov. sp. nov., a new anaerobic, alkaliphilic proteolytic bacterium capable of reducing Fe(III) and sulfur.

An obligately alkaliphilic, anaerobic, proteolytic bacterium was isolated from a sample of Tanatar III soda lake sediment (Altai region, Russia) and designated as strain Z-1701. Cells of strain Z-1701 were short, straight, motile Gram-stain-positive rods. Growth of Z-1701 obligately depended on the presence of sodium carbonate. Strain Z-1701 could utilize various peptides mixtures, such as beef and yeast extracts, peptone, soytone, trypticase and tryptone, as well as such proteins as albumin, gelatin and sodium caseinate. It was able to grow oligotrophically with 0.02 g l yeast extract as the sole energy and carbon source. Carbohydrates did not support the growth of strain Z-1701. The main products released during the growth of strain Z-1701 on tryptone were formate, acetate and ammonium. Strain Z-1701 was able to reduce ferrihydrite, Fe(III)-EDTA, anthraquinone-2,6-disulfonate and elemental sulfur, using proteinaceous substrates as electron donors. In all cases the presence of the electron acceptor in the medium stimulated growth. The main cellular fatty acids were iso-C, iso-C aldehyde, iso-C ω6, C, iso-C aldehyde, C aldehyde and C. The DNA G+C content of the isolate was 43.9 mol%. Phylogenetic analysis based on the concatenated alignment of 120 protein-marker sequences revealed that strain Z-1701 falls into a cluster with the genus , family . 16S rRNA gene sequence identity between strain Z-1701 and species were 88.3-89.75 %. On the basis of its phenotypic characteristics and phylogenetic position, the novel isolate is considered to be a representative of a novel genus and species for which the name gen. nov., sp. nov. is proposed, with Z-1701 (=JCM 32929=DSM 109060=VKM B-3261) as its type strain.