title: Natranaerobius thermophilus gen. nov., sp. nov., a halophilic, alkalithermophilic bacterium from soda lakes of the Wadi An Natrun, Egypt, and proposal of Natranaerobiaceae fam. nov. and Natranaerobiales ord. nov.
abstract: Novel halophilic, alkalithermophilic, Gram-type-positive bacterial strains were isolated from sediment of alkaline, hypersaline lakes of the Wadi An Natrun, Egypt. Cells of strain JW/NM-WN-LFT were rod-shaped, non-spore-forming and non-motile. Strain JW/NM-WN-LFT grew (at pH55 degrees C 9.5) between 35 and 56 degrees C, with an optimum at 53 degrees C. The pH55 degrees C range for growth was 8.3-10.6, with an optimum at pH55 degrees C 9.5 and no growth at pH55 degrees C 8.2 or below, or at pH55 degrees C 10.8 or above. At the optimum pH and temperature, the strain grew in the Na+ range of 3.1-4.9 M (1.5-3.3 M added NaCl) and optimally between 3.3 and 3.9 M Na+ (1.7-2.3 M added NaCl). Strain JW/NM-WN-LFT utilized fructose, cellobiose, ribose, trehalose, trimethylamine, pyruvate, Casamino acids, acetate, xylose and peptone as carbon and energy sources. Fumarate (20 mM), S2O3(2-) (20 mM), NO3- (20 mM) and iron(III) citrate (20 mM) were utilized as electron acceptors. During growth on sucrose, the isolate produced acetate and formate as major fermentation products. Main cellular fatty acids were iso-branched 15:0, i17:0 dimethylacetal and 16:0 dimethylacetal. The G+C content of genomic DNA was 40.4 mol% (HPLC). On the basis of genotypic and phenotypic characteristics, it is proposed that strain JW/NM-WN-LFT represents a novel genus and species, Natranaerobius thermophilus gen. nov., sp. nov. The type strain is JW/NM-WN-LFT (=DSM 18059T=ATCC BAA-1301T). Based on 16S rRNA gene sequence analysis, the strain forms a novel lineage within the class 'Clostridia' and clusters with uncultivated bacteria and unidentified strains retrieved from alkaline, hypersaline environments. The phylogenetic data suggest that the lineage represents a novel family, Natranaerobiaceae fam. nov., and order, Natranaerobiales ord. nov.
authors.affiliation: Department of Microbiology, University of Georgia, Athens, GA 30602, USA.
authors.forename: Noha M
authors.initials: NM
authors.lastname: Mesbah
authors.affiliation: University of Tennessee, Knoxville, TN 37932, USA.
authors.forename: David B
authors.initials: DB
authors.lastname: Hedrick
authors.affiliation: University of Tennessee, Knoxville, TN 37932, USA.
authors.forename: Aaron D
authors.initials: AD
authors.lastname: Peacock
authors.affiliation: Department of Microbial Pathogenicity, Helmholtz Center for Infection, Research, Inhoffenstrasse 7, D-38124 Braunschweig, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Rohde
authors.affiliation: Department of Microbiology, University of Georgia, Athens, GA 30602, USA.
authors.forename: Juergen
authors.initials: J
authors.lastname: Wiegel
mesh_terms: D015373:Bacterial Typing Techniques; D002254:Carbonates; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D004534:Egypt; D005227:Fatty Acids / Q000032:analysis; D005618:Fresh Water / Q000737:chemistry / Q000382:microbiology*; D020459:Genes, rRNA; D005838:Genotype; D019015:Geologic Sediments / Q000382:microbiology*; D006094:Gram-Positive Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000378:metabolism*
chemical_list: D002254:Carbonates; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D012965:Sodium Chloride; C005686:sodium carbonate