title: Anoxynatronum sibiricum gen.nov., sp.nov. alkaliphilic saccharolytic anaerobe from cellulolytic community of Nizhnee Beloe (Transbaikal region).
abstract: New alkaliphilic anaerobic fermentative bacteria, strains Z-7981 and Z-7981', with Gram-positive cell walls, were isolated from the cellulolytic community from the soda lake Nizhnee Beloye, south-east of Baikal. Cells were motile rods, which differed in dimensions but, according to 98% DNA/DNA homology, belonged to the same species. Strain Z-7981 was chosen as the type and studied in detail. It did not produce spores and its cells were non-thermoresistant. It was a true alkaliphile with a growth range from pH 7.1 to pH 10.1 and optimal pH for growth at pH 9.1. It was obligately dependent on Na(+) and carbonate ions but not on Cl(-). Growth occurred in media with total sodium content from 0.076 M to 1.27 M Na(+ )with a broad optimum from 0.25 to 0.86 M Na(+). Growth showed an optimum at 35 degrees C, with absence of growth above 46 degrees C. The organism was aerotolerant and was capable of fermentation in non-reducing medium at less than 4.75% O(2) in the gas phase. Strain Z-7981 fermented mono- and disaccharides, sugar alcohols, but only glutamate and cysteine among the amino acids, and the proteinaceous substrates, chitin and dried Spirulina biomass. Fermentation products were acetate and ethanol. Fe(3+) was reduced in a process that yielded no energy. Phylogenetically the new organism belonged to cluster XI of the Gram-positive bacteria with low G+C content and its closest neighboring taxon was Tindallia magadiensis. However, according to its phenotypic and genotypic characters it did not belong to any known genus from this group. We suggest a new genus and species with the name Anoxynatronum sibiricum and strain Z-7981 as its type (=DSM15060).
authors.affiliation: Laboratory of Relict Microbial Communities, Institute of Microbiology RAS, Prospect 60-let Oktyabrya 7/2, 117312 Moscow, Russia. egarnova@yahoo.com
authors.forename: Elena S
authors.initials: ES
authors.lastname: Garnova
authors.forename: Tatjana N
authors.initials: TN
authors.lastname: Zhilina
authors.forename: Tatjana P
authors.initials: TP
authors.lastname: Tourova
authors.forename: Anatoli M
authors.initials: AM
authors.lastname: Lysenko
mesh_terms: D001421:Bacteria, Anaerobic / Q000145:classification* / Q000235:genetics*; D050260:Carbohydrate Metabolism; D002482:Cellulose / Q000737:chemistry; D003470:Culture Media / Q000494:pharmacology; D004247:DNA / Q000648:ultrastructure; D004275:DNA, Ribosomal / Q000235:genetics*; D005285:Fermentation; D005838:Genotype; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007501:Iron / Q000737:chemistry; D008956:Models, Chemical; D010641:Phenotype; D010802:Phylogeny; D011485:Protein Binding; D012336:RNA, Ribosomal, 16S / Q000378:metabolism; D012964:Sodium / Q000737:chemistry / Q000494:pharmacology; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D003470:Culture Media; D004275:DNA, Ribosomal; D007477:Ions; D012336:RNA, Ribosomal, 16S; D002482:Cellulose; D004247:DNA; D012964:Sodium; D007501:Iron