title: Desulfomicrobium thermophilum sp. nov., a novel thermophilic sulphate-reducing bacterium isolated from a terrestrial hot spring in Colombia.
abstract: A moderately thermophilic, sulphate-reducing bacterium, designated strain P6-2(T), was isolated from a terrestrial hot spring located at a height of 2,500 m in the Andean region, Colombia (5 degrees 43'69''N, 73 degrees 6'10''W). Cells of strain P6-2(T) were rod-shaped, stained Gram-negative and were motile by means of a single polar flagellum. The strain grew lithotrophically with H(2) as the electron donor and organotrophically on lactate, pyruvate, ethanol, malate, fumarate, n-propanol and succinate in the presence of sulphate as the terminal electron acceptor. Fumarate and pyruvate was fermented. Strain P6-2(T) grew optimally at 55 degrees C (range 37-60 degrees C), pH 6.6 (range 5.8-8.8) in the presence of 0.5% NaCl (range 0-4.5%) with lactate and sulphate and produced acetate, CO(2) and H(2)S as the major end-products. Sulphate, sulphite and thiosulphate could be used as electron acceptors but not elemental sulphur or nitrate. The G + C content of the genomic DNA was 58.7 mol%. The 16S rRNA sequence analysis indicated that strain P6-2(T) was a member of the class Deltaproteobacteria, domain Bacteria with Desulfomicrobium baculatum being the closest relative (similarity value of 94%). Phylogeny of genes encoding alpha- and beta-subunits of the dissimilatory sulphite reductase (dsrAB genes) supported its affiliation to members of the genus Desulfomicrobium. On the basis of this evidence, we propose to assign strain P6-2(T) as new species of the genus Desulfomicrobium, D. thermophilum sp. nov., with strain P6-2(T) as the type strain (= DSM 16697(T) = CCUG 49732(T)).
authors.affiliation: IRD, UMR 180 Microbiologie et Biotechnologie des Environnements Chauds, IFR-BAIM, ESIL, Universités de Provence et de la Mediterranée, Case 925, 13288, Marseille, France.
authors.forename: France
authors.initials: F
authors.lastname: Thevenieau
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Fardeau
authors.forename: Bernard
authors.initials: B
authors.lastname: Ollivier
authors.forename: Catherine
authors.initials: C
authors.lastname: Joulian
authors.forename: Sandra
authors.initials: S
authors.lastname: Baena
mesh_terms: D000433:1-Propanol / Q000378:metabolism; D000144:Acids, Acyclic / Q000378:metabolism; D001482:Base Composition / Q000235:genetics; D003105:Colombia; D000431:Ethanol / Q000378:metabolism; D016946:Gram-Negative Aerobic Rods and Cocci / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D045482:Hot Springs / Q000382:microbiology*; D006358:Hot Temperature; D006859:Hydrogen / Q000378:metabolism; D010084:Oxidation-Reduction; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013431:Sulfates / Q000378:metabolism; D014871:Water Microbiology
chemical_list: D000144:Acids, Acyclic; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D013431:Sulfates; D000431:Ethanol; D006859:Hydrogen; D000433:1-Propanol