[Show abstract][Hide abstract] ABSTRACT: A new anaerobic alkaliphilic H2-producer was isolated from a serpentinite-hosted ecosystem.•16S rDNA sequence analysis of strain PROH2 revealed its assignment to a novel Clostridium species.•The maximum H2 productions were obtained at 37 °C, initial pH 9.5 and 2 g/L of glucose.•The isolate is a good candidate for H2 production under alkaline conditions due to its high H2 yield.•It is the first anaerobic microorganism producing H2 at both high pH and low salinity.
International Journal of Hydrogen Energy 11/2014; 39. · 3.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A novel anaerobic, alkaliphilic, Gram-positive staining bacterium was isolated from a hydrothermal chimney in the Prony Bay, New Caledonia. This strain designated FatMR1(T) grew at temperatures from 20 to 55 °C (optimum 37 °C) and at pH between 7.5 and 10.5 (optimum 8.8-9). NaCl is not required for growth (optimum 0.2-0.5 %), but is tolerated up to 3 %. Sulfate, thiosulfate, elemental sulfur, sulfite, nitrate and nitrite are not used as terminal electron acceptors. Strain FatMR1(T) fermented pyruvate, yeast extract, peptone and biotrypcase and used fructose as the only sugar. The main fermentation products from fructose and proteinaceous compounds (e.g. peptone and biotrypcase) were acetate, H2 and CO2. Crotonate was disproportionated to acetate and butyrate. The predominant cellular fatty acids were C14:0 and C16:0. The G + C content of the genomic DNA was 37.1 mol %. On the basis of phylogenetic, genetic, and physiological properties, strain FatMR1(T) (=DSM 25890(T), =JCM 18390(T)) belonging to the phylum Firmicutes, class Clostridia, order Clostridiales, is proposed as a novel species of the genus Alkaliphilus, A. hydrothermalis sp. nov.
Extremophiles : life under extreme conditions. 10/2014;
[Show abstract][Hide abstract] ABSTRACT: Strain LTF Kr01, a novel mesophilic, anaerobic, halotolerant, rod-shaped bacterium was isolated from a drain at the bottom of a corroded kerosene storage tank of the Société Tunisienne des Industries de Raffinage (STIR), Bizerte, North Tunisia. Cells are Gram- positive rods, and occur singly or in pairs, motile by one lateral flagellum. Strain LTF Kr01 grows at temperatures between 15°C and 40°C (optimum 30°C), pH between 5.5 and 8.1 (optimum 7.2) and NaCl concentration between 0 and 50 g l-1 (optimum 5 g l-1). It reduces thiosulfate and elemental sulfur into sulfide, but not sulfate and or sulfite. It utilizes a large number wide range of carbohydrates (cellobiose, D-glucose, D-fructose, D-mannitol,D-ribose, D-sucrose, D-xylose, D-maltose, D-galactose, starch, and trehalose), and produces acetate, CO2, and H2, as end products from glucose fermentation. The DNA G+C content is 37.4 mol %. The predominant cellular fatty acids are C14:0 and C16:0. Phylogenetic analysis of the 16SrRNA gene sequence suggests that Fusibacter tunisiensis is its closest relative (identity of 94.6%). Based on phenotypic, phylogenetic and genotypic taxonomic characteristics, strain LTF Kr01T is proposed described as a novel species of the genus Fusibacter, order Clostridiales for which the name F. bizertensis sp. nov. is proposed. The type strain is LTF Kr01T (= DSM 28034 =JCM 19376).
International journal of systematic and evolutionary microbiology. 10/2014;
[Show abstract][Hide abstract] ABSTRACT: RNA-seq was used to study the response of Desulfovibrio hydrothermalis, isolated from a deep-sea hydrothermal chimney on the East-Pacific Rise at a depth of 2,600 m, to various hydrostatic pressure growth conditions. The transcriptomic datasets obtained after growth at 26, 10 and 0.1 MPa identified only 65 differentially expressed genes that were distributed among four main categories: aromatic amino acid and glutamate metabolisms, energy metabolism, signal transduction, and unknown function. The gene expression patterns suggest that D. hydrothermalis uses at least three different adaptation mechanisms, according to a hydrostatic pressure threshold (HPt) that was estimated to be above 10 MPa. Both glutamate and energy metabolism were found to play crucial roles in these mechanisms. Quantitation of the glutamate levels in cells revealed its accumulation at high hydrostatic pressure, suggesting its role as a piezolyte. ATP measurements showed that the energy metabolism of this bacterium is optimized for deep-sea life conditions. This study provides new insights into the molecular mechanisms linked to hydrostatic pressure adaptation in sulfate-reducing bacteria.
PLoS ONE 09/2014; 9(9):e106831. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To date, xylanases have expanded their use in many processing industries, such as pulp, paper, food, and textile. This study aimed the production and partial characterization of a thermostable xylanase from a novel thermophilic anaerobic bacterium Caldicoprobacter algeriensis strain TH7C1(T) isolated from a northeast hot spring in Algeria. The obtained results showed that C. algeriensis xylanase seems not to be correlated with the biomass growth profile whereas the maximum enzyme production (140.0 U/ml) was recorded in stationary phase (18 h). The temperature and pH for optimal activities were 70 °C and 11.0, respectively. The enzyme was found to be stable at 50, 60, 70, and 80 °C, with a half-life of 10, 9, 8, and 4 h, respectively. Influence of metal ions on enzyme activity revealed that Ca(+2) enhances greatly the relative activity to 151.3 %; whereas Hg(2+) inhibited significantly the enzyme. At the best of our knowledge, this is the first report on the production of xylanase by the thermophilic bacterium C. algeriensis. This thermo- and alkaline-tolerant xylanase could be used in pulp bleaching process.
Applied biochemistry and biotechnology 08/2014; · 1.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The shallow submarine hydrothermal field of the Prony Bay (New Caledonia) discharges hydrogen- and methane-rich fluids with low salinity, temperature (<40°C) and high pH (11) produced by the serpentinization reactions of the ultramafic basement into the lagoon seawater. They are responsible for the formation of carbonate chimneys at the lagoon seafloor. CE-SSCP fingerprinting, quantitative PCR and sequence analysis of 16S rRNA genes revealed changes in microbial community structure, abundance and diversity depending on the location, water depth and structure of the carbonate chimneys. The low archaeal diversity was dominated by few uncultured Methanosarcinales similar to those found in other serpentinization-driven submarine and subterrestrial ecosystems (e.g. Lost City, The Cedars). The most abundant and diverse bacterial communities were mainly composed of Chloroflexi, Deinococcus-Thermus, Firmicutes, and Proteobacteria. Functional gene analysis revealed similar abundance and diversity of both Methanosarcinales methanoarchaea and Desulfovibrionales- and Desulfobacterales sulfate-reducers in the studied sites. Molecular studies suggest that redox reactions involving hydrogen, methane and sulfur compounds (e.g. sulfate) are the energy driving forces of the microbial communities inhabiting the Prony hydrothermal system.
[Show abstract][Hide abstract] ABSTRACT: The thermophilic sulfate-reducing archaeon Archaeoglobus fulgidus strain VC-16 (DSM 4304), which is known to oxidize fatty acids and n-alkenes, was shown to oxidize saturated hydrocarbons (n-alkanes in the range C10-C21) with thiosulfate or sulfate as a terminal electron acceptor. The amount of n-hexadecane degradation observed was in stoichiometric agreement with the theoretically expected amount of thiosulfate reduction. One of the pathways used by anaerobic microorganisms to activate alkanes is addition to fumarate that involves alkylsuccinate synthase as a key enzyme. A search for genes encoding homologous enzymes in A. fulgidus identified the pflD gene (locus-tag AF1449) that was previously annotated as a pyruvate formate lyase. A phylogenetic analysis revealed that this gene is of bacterial origin and was likely acquired by A. fulgidus from a bacterial donor through a horizontal gene transfer. Based on three-dimensional modeling of the corresponding protein and molecular dynamic simulations, we hypothesize an alkylsuccinate synthase activity for this gene product. The pflD gene expression was upregulated during the growth of A. fulgidus on an n-alkane (C16) compared with growth on a fatty acid. Our results suggest that anaerobic alkane degradation in A. fulgidus may involve the gene pflD in alkane activation through addition to fumarate. These findings highlight the possible importance of hydrocarbon oxidation at high temperatures by A. fulgidus in hydrothermal vents and the deep biosphere.The ISME Journal advance online publication, 24 April 2014; doi:10.1038/ismej.2014.58.
[Show abstract][Hide abstract] ABSTRACT: Members of the deep-branching order Thermotogales are widespread in
various terrestrial, submarine and subterrestrial extreme environments.
This bacterial order included both thermophilic and hyperthermophilic
anaerobic microorganisms so far pertaining to ten genera. It is only
recently (2011) that cultivation of a mesophilic member of this order
belonging to a novel genus, Mesotoga, has been successful. All members,
with the exception of Mesotoga spp., are recognized as high hydrogen
producers having possible applications in biotechnology with a peculiar
emphasis for members of the genus Thermotoga (e.g. T. maritima
and T. neapolitana). The ecology, phylogeny and metabolism linked to
hydrogen production of these bacteria, are reviewed.
Microbial BioEnergy: Hydrogen Production, Edited by Zannoni D, De Philippis R, 03/2014: chapter Members of the Order Thermotogales: From Microbiology to Hydrogen Production: pages 199; Springer., ISBN: 978-94-017-8553-2
[Show abstract][Hide abstract] ABSTRACT: A novel thermotolerant, anaerobic, Gram-positive staining, spore-forming bacterium was isolated from a hydrothermal chimney in the Prony Bay, New Caledonia. This strain designated FatNI3T grew at temperatures from15 to 55 °C (optimum 30°C) and at pH between 5.8 and 8.9 (optimum 7.7). It is slightly halophilic requiring at least 0.5% NaCl for growth (optimum 2.5-3.0%), and supporting it up to 6 %. Sulfate, thiosulfate, elemental sulfur, sulfite, nitrate and nitrite were not used as terminal electron acceptors. Growth of strain FatNI3T was inhibited in the presence of sulfite (2 mM) or nitrite (2 mM). Strain FatNI3T fermented cellobiose, glucose, mannose, maltose, sucrose, galactose, lactose, ribose, fructose, rhamnose, raffinose, xylose, yeast extract, peptone and biotrypcase. The main fermentation products from glucose metabolism were acetate, ethanol, H2 and CO2. The predominant cellular fatty acids were iso-C15:0, anteiso-C15:0. The main polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, glycolipids and phospholipids. The G+C content of the genomic DNA was 36.6 mol%. On the basis of phylogenetic and physiological properties, strain FatNI3T (= DSM 25904 = JCM 18391) belonging to the phylum Firmicutes, class Clostridia, order Clostridiales, is proposed as a novel species of the genus Vallitalea, V. pronyensis sp. nov..
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 01/2014; · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A novel anaerobic, chemo-organotrophic sulfate-reducing bacterium, designated strain Olac 40T, was isolated from a Tunisian wastewater digestor. Cells were curved motile rods or vibrios (5.0-7.0 x 0.5 μm). Strain Olac 40T grew at temperatures between 15 and 50°C (optimum 40°C), and at pH between 5.0 and 9.0 (optimum 7.1). It did not require NaCl for growth but tolerated it up to 50 g l-1 (optimum 2 g l-1). In the presence of sulfate or thiosulfate, strain Olac 40T used lactate, pyruvate and formate as energy sources. Growth was observed on H2 only in the presence of acetate as carbon source. In the presence of sulfate or thiosulfate, the end-products of lactate oxidation were acetate, sulfide and CO2. Sulfate, thiosulfate and sulfite were used as terminal electron acceptors, but not elemental sulfur, nitrate and nitrite. The genomic DNA G+C content of strain Olac 40T was 70 mol %. Profile of polar lipids consisted of phosphatidylglycerol, phosphatidylethanolamine, aminophospholipid and four phospholipids The main fatty acids were C16: 0, anteiso-C15: 0 and iso-C15: 0. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain Olac 40T was affiliated with the family Desulfovibrionaceae within the class Deltaproteobacteria. On the basis of the 16S rRNA gene sequence comparisons and physiological characteristics, strain Olac 40T is proposed to be assigned to a new species of the genus Desulfocurvus, for which the name Desulfocurvus thunnarius is proposed. The type strain is Olac 40T (=DSM 26129T= JCM 18546T).
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 06/2013; · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An anaerobic thermophilic bacterium designated CA9F1 was isolated from a thermal spring in France. Strain CA9F1 was observed to grow at temperatures between 55 and 70 °C (optimum 65 °C) and at pH between 6.8 and 9.5 (optimum pH 7.4). Strain CA9F1 does not require salt for growth (0-10 g l(-1) NaCl), with an optimum at 1 g l(-1). The DNA G+C content was determined to be 38.5 mol% (Tm). The major cellular fatty acids identified were C15:0, C16:0, C17:0 iso. Based on phenotypic, chemotaxonomic and genotypic properties, strain CA9F1 was identified as Thermovenabulum gondwanense and this species was studied in more detail. Strain CA9F1 is a Gram-positive bacterium which forms a complex and regular multilayered cell wall structure, here characterised as being due to the presence of an S-layer. The network covers the entire cell surface and forms a hexagonal structure resembling that observed for Deinococcus radiodurans. The main protein component of the S-layer possesses domains comparable to that of the S-layer protein of Halothermothrix orenii. The characteristics of the strain were compared to that of T. gondwanese R270(T) isolated from microbial mats thriving in the thermal waters of a Great Artesian Basin bore runoff channel at 66 °C, in Australia. Significant differences were observed between CA9F1 and the type strain. One of the major physiological differences is the inability of CA9F1 to reduce Fe(III). An emended description of T. gondwanense is given.
Antonie van Leeuwenhoek 06/2013; · 2.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A novel obligately anaerobic, non-spore-forming, rod-shaped mesophilic, halophilic bacterium staining Gram-negative, was isolated from sediments of Guaymas basin. The strain, designated Ra1766G1T, grew at 20-40 °C (optimum 30-35 °C) and at pH 6.0-8.0 (optimum pH 6.5-7.5). It required 0.5%-7.5% NaCl (optimum 2%-3%) for growth. Sulfate, thiosulfate, elemental sulfur, sulfite, fumarate, nitrate and nitrite were not used as terminal electron acceptors. Strain Ra1766G1T used cellobiose, glucose, mannose, maltose, arabinose, raffinose, galactose, ribose, saccharose, pyruvate and xylose as electron donors. The main fermentation product from glucose metabolism was acetate. The predominant cellular fatty acids were anteiso-C15:0, iso-C15:0, anteiso DMA-C15:0 and C16:0. The main polar lipids consisted of diphosphatiglycerol, phosphatidylglycerol, glycolipids and phospholipids.The G+C content of the genomic DNA was 31.2 mol%. The closest phylogenetic relatives of Ra1766G1T were Natranaerovirga pectinivoraT (92.4% similarity), Natranaerovirga hydrolytica (90.2% similarity) and Defluviitalea saccharophilaT (88.9% similarity). On the basis of phylogenetic inference and phenotypic properties, strain Ra1766G1T (= DSM 24848T = JCMT= 16313) is proposed as the type strain of a novel species of a novel genus, Vallitalea guaymasensis gen. nov., sp. nov.
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 02/2013; · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Strain VNs100T, a novel mesophilic anaerobic rod-cocoid-shaped bacterium, having a sheath-like outer structure (toga) was isolated from a water sample collected in the area of underground gas storage. It was non-motile with cells appearing singly (2-4 μm long x 1-2 μm wide), in pairs, or as long chains and stained Gram-negative. Strain VNs100T was heterotrophic, able to use arabinose, cellobiose, fructose, galactose, glucose, lactose, lactate, mannose, maltose, raffinose, ribose, sucrose and xylose as energy sources only in the presence of elemental sulfur as terminal electron acceptor. Acetate, CO2 and sulfide were the end-products of sugar metabolism. Hydrogen was not detected. Elemental sulfur, but not thiosulfate, sulfate and sulfite, were reduced into sulfide. It grew at temperatures between 30°C and 50°C (optimum 45°C), at pH between 6.2 and 7.9 (optimum 7.3-7.5) and at NaCl concentrations between 0 and 15 g.L-1 (optimum 2 g.L-1). The DNA G+C content was 47.5 mol%. The main cellular fatty acid was C16:0. Phylogenetic analysis of the small-subunit (SSU) ribosomal RNA (rRNA) gene sequence indicated that strain VNs100T had as its closest relatives 'Mesotoga sulfurireducens' (97.1 % similarity) and Mesotoga prima (similarity of 97.1 % and 97.7 % with each of its two genes respectively) within the order Thermotogales. Hybridization between strain VNS100T and 'Mesotoga sulfurireducens' and between strain VNS100T and Mesotoga prima is 12.9% and 20.6 %, respectively. Based on phenotypic, phylogenetic and taxonomic characteristics, strain VNs100T is proposed as a novel species of genus Mesotoga within the family Thermotogaceae, order Thermotogales. The name Mesotoga infera, sp. nov. is proposed. The type strain is VNs100T (= DSM 25546 = JCM 18154).
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 02/2013; · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: AM13 is a piezophilic, mesophilic, hydrogenotrophic sulfate-reducing bacterium collected from a deep-sea hydrothermal chimney on the East Pacific Rise (2,600 m depth, 13°N). We report the genome sequence of this bacterium, which includes a 3,702,934-bp chromosome and a circular plasmid of 5,328 bp.
[Show abstract][Hide abstract] ABSTRACT: Gram-positive spore-forming sulfate reducers and particularly members of the genus Desulfotomaculum are commonly found in the subsurface biosphere by culture based and molecular approaches. Due to their metabolic versatility and their ability to persist as endospores. Desulfotomaculum spp. are well-adapted for colonizing environments through a slow sedimentation process. Because of their ability to grow autotrophically (H2/CO2) and produce sulfide or acetate, these microorganisms may play key roles in deep lithoautotrophic microbial communities. Available data about Desulfotomaculum spp. and related species from studies carried out from deep freshwater lakes, marine sediments, oligotrophic and organic rich deep geological settings are discussed in this review.
Frontiers in Microbiology 01/2013; 4:362. · 3.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Human African trypanosomiasis (HAT) is caused by trypanosomes transmitted to humans by the tsetse fly, in which they accomplish their development into their infective metacyclic form. The crucial step in parasite survival occurs when it invades the fly midgut. Insect digestive enzymes and immune defenses may be involved in the modulation of the fly's vector competence, together with bacteria that could be present in the fly's midgut. In fact, in addition to the three bacterial symbionts that have previously been characterized, tsetse flies may harbor additional bacterial inhabitants. This review focuses on the diversity of the bacterial flora in Glossina, with regards to the fly species and their geographical distribution. The rationale was (i) that these newly identified bacteria, associated with tsetse flies, may contribute to vector competence as was shown in other insects and (ii) that differences may exist according to fly species and geographic area. A more complete knowledge of the bacterial microbiota of the tsetse fly and the role these bacteria play in tsetse biology may lead to novel ways of investigation in view of developing alternative anti-vector strategies for fighting human-and possibly animal-trypanosomiasis.
Frontiers in Cellular and Infection Microbiology 01/2013; 3:34. · 2.62 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Here, we report the draft genome sequence of Desulfotomaculum hydrothermale, a sulfate-reducing, spore-forming bacterium isolated from a Tunisian hot spring. The genome is composed of 2.7 Mb, with a G+C content of 49.48%, and it contains 2,643 protein-coding sequences.
[Show abstract][Hide abstract] ABSTRACT: Desulfosporosinus species are sulfate-reducing bacteria belonging to the Firmicutes. Their genomes will give insights into the genetic repertoire and evolution of sulfate reducers typically thriving in terrestrial environments and able to degrade toluene (Desulfosporosinus youngiae), to reduce Fe(III) (Desulfosporosinus meridiei, Desulfosporosinus orientis), and to grow under acidic conditions (Desulfosporosinus acidiphilus).
Journal of bacteriology 11/2012; 194(22):6300-1. · 3.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A novel anaerobic thermophilic sulfate-reducing bacterium designated LINDBHT1 was isolated from an anaerobic treating abattoir wastewaters digestor in Tunisia. Strain LINDBHT1 grew at temperatures between 50 and 65°C (optimum 55-60°C), and at pH between 5.9 and 9.2 (optimum pH 6.0-6.8). Strain LINDBHT1 required salt for growth (1-40 g NaCl l-1), with an optimum at 20-30g/L. In the presence of sulfate as terminal electron acceptor, strain LINDBHT1 used H2/CO2, propanol, butanol and ethanol as carbon and energy sources but fumarate, formate, lactate and pyruvate were not utilized. Butanol was converted to butyrate, while propanol and ethanol were oxidized to propionate and acetate, respectively. Sulfate, sulfite and thiosulfate were utilized as terminal electron acceptors but elemental sulfur, iron (III), fumarate, nitrate and nitrite were not used. The G+C content of the genomic DNA was 44.4 mol %. Phylogenetic analysis of the small-subunit (SSU) ribosomal RNA (rRNA) gene sequence indicated that strain LINDBHT1 was affiliated to the genus Desulfotomaculum with Desulfotomaculum halophilum and Desulfotomaculum alkaliphilum as its closest phylogenetic relatives (about 89% of similarity). This bacterium will constitute a new species of the genus Desulfotomaculum, Desulfotomaculum peckii (the type strain LINDBHT1T = DSM 23769T = JCM 17209T).
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 10/2012; · 2.11 Impact Factor