Tepidibacter aestuarii sp. nov., isolated from the Bach Dang Estuary, Haiphong, Vietnam

A mesophilic, anaerobic, endospore-forming, fermentative bacterium designated strain 8C15bT was isolated from bank sediment of the Bach Dang Estuary, Haiphong, Vietnam. The Bach Dang Estuary, where Haiphong harbour is located, is subject to strong anthropogenic influence, resulting in high concentrations of black carbon and heavy metals. Strain 8C15bT grew optimally at 30 °C, pH 7.5 and with 2.5 % (w/v) NaCl. The main cellular fatty acids consisted of iso-C15 : 0 (51 %), iso-C15:1 ω7c (32 %) and iso-C13 : 0 (5 %). Genomic considerations of strain 8C15bT and comparisons with the phylogenetically closest strains of the genus Tepidibacter provide evidence that Tepidibacter thalassicus SC562T (=DSM 15285T), Tepidibacter formicigenes DV1184T (=DSM 15518T), Tepidibacter mesophilus B1T (=JCM 16806T) and strain 8C15bT could be differentiated at the species level. We propose the name Tepidibacter aestuarii sp. nov. for the type strain 8C15bT (=JCM 35983T=KCTC 25692T). Finally, the nickel-tolerance properties of strain 8C15bT are highlighted in this study.

Thermospira aquatica gen. nov., sp. nov., a novel thermophilic spirochete isolated from a Tunisian hot spring, and description of the novel family Thermospiraceae

A novel thermophilic, anaerobic bacterium, strain F1F22^T, was isolated from hot spring water collected in northern Tunisia. The cells were non-motile, Gram-negative and helical with hooked ends, 0.5×10-32 µm in size. Growth of the strain was observed at 45-70 °C (optimum, 55 °C), in 0.0-1.0 % (w/v) NaCl (optimum without NaCl) and at pH 6.5-8.5 (optimum, pH 7.5). Yeast extract was required for growth, and the strain grew on glucose, sucrose and maltose. The major fatty acids were C_16:0 (40.2 %), iso-C_16: 0 (30.2 %) and C_16 :0 DMA (14.5 %). The genome consisted of a circular chromosome (2.5 Mb) containing 2672 predicted protein-encoding genes with a G+C content of 43.15 mol %. Based on a comparative 16S rRNA gene sequence analysis, strain F1F22^T formed a deeply branching lineage within the phylum Spirochaetota, class Spirochaetia, order Brevinematales, and had only low sequence similarity to other species of the phylum (lower than 83 %). Genome-based analysis of average nucleotide identity and digital DNA-DNA hybridization of strain F1F22^T with Treponema caldarium DSM 7334^T, Brevinema andersonii ATCC 43811^T and Spirochaeta thermophila DSM 6578^T showed values between 63.26 and 63.52 %, and between 20 and 25 %. Hence, we propose strain F1F22^T as a representative of a novel family (Thermospiraceae fam. nov.), genus and species of Brevinematales: Thermospira aquatica gen. nov., sp. nov. (type strain F1F22^T=JCM 31314^T=DSM 101182^T).

Virgibacillus ainsalahensis sp. nov., a Moderately Halophilic Bacterium Isolated from Sediment of a Saline Lake in South of Algeria

A Gram-positive, moderately halophilic, endospore-forming bacterium, designated MerV^T, was isolated from a sediment sample of a saline lake located in Ain Salah, south of Algeria. The cells were rod shaped and motile. Isolate MerV^T grew at salinity interval of 0.5-25% NaCl (optimum, 5-10%), pH 6.0-12.0 (optimum, 8.0), and temperature between 10 and 40 °C (optimum, 30 °C).The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, a glycolipid, a phospholipid, and two lipids, and MK-7 is the predominant menaquinone. The predominant cellular fatty acids were anteiso C_15:0 and anteiso C_17:0. The DNA G+C content was 45.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain MerV^T was most closely related to Virgibacillus halodenitrificans (gene sequence similarity of 97.0%). On the basis of phenotypic, chemotaxonomic properties, and phylogenetic analyses, strain MerV^T (=DSM = 28944^T) should be placed in the genus Virgibacillus as a novel species, for which the name Virgibacillus ainsalahensis is proposed.

Paludifilum halophilum gen. nov., sp. nov., a thermoactinomycete isolated from superficial sediment of a solar saltern

A novel filamentous, halophilic, thermotolerant bacterium, strain SMBg3T was isolated from superficial sediment of a solar saltern in Sfax, Tunisia. The isolate is Gram-staining-positive, aerobic, catalase- and oxidase-positive. Optimum growth occurred at 40-45 °C, with 10 % (w/v) NaCl and at pH 8.0-9.0. Long and well developed aerial and substrate mycelia, with long chains of fluorescent and circular spores, were observed on all tested media. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SMBg3T belongs to an independent phylogenetic lineage of the family Thermoactinomycetaceae and shows a gene sequence similarity of 94 % with Desmospora activa DSM 45169T 94.2 % with Kroppenstedtia eburnea DSM 45196T, 94.3 % with Kroppenstedtia guangzhouensis KCTC 29149T, 94.3 % with Melghirimyces algeriensisDSM 45474T and 94.5 % with Salinithrix halophila CECT 8506T. The predominant menaquinone is MK-7, but MK-8 and some minor unidentified components are also present in trace amounts. The major cellular fatty acids are anteiso-C15 : 0, iso-C15 : 0 and iso-C17 : 0. In addition to four major polar lipids identified as phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and phosphatidylmethylethanolamine, five minor unknown lipids were detected in cell membranes. The DNA G+C content of strain SMBg3T is 51.2 mol%. Strain SMBg3T is distinct from recognized genera of the family Thermoactinomycetaceae by morphological, biochemical and chemotaxonomic characteristics. On the basis of physiological and phylogenetic data, strain SMBg3T represents a novel species of a new genus in the family Thermoactinomycetaceae for which the name Paludifilum halophilum gen. nov., sp. nov. is proposed. The type strain of the type species is SMBg3T (=DSM 102817T=CCUG 68698T).

Analysis of a population of magnetotactic bacteria of the Gulf of Gabès, Tunisia

The occurrence of magnetotactic bacteria (MTB) on a Tunisian marine coast exposed to heavy metals pollution (Sfax, Gulf of Gabès, Mediterranean Sea) was investigated. The MTB population of this Southern Mediterranean coast was compared to the MTB populations previously investigated on the French Northern Mediterranean coast. A dominant MTB coccus morphotype was observed by microscopy analysis. By pyrosequencing technology, the analysis of the 16S ribosomal RNA (rDNA) revealed as much as 33 operational taxonomic sequence units (OTUs) close to sequences of MTB accessible in the databases. The majority were close to MTB sequences of the "Med group" of α-Proteobacteria. Among them, a dominant OTU_001 (99 % of the MTB sequences) affiliated within the Magnetococcales order was highlighted. Investigating the capacities of this novel bacterium to be used in bioremediation and/or depollution processes could be envisaged.

Bacterial ecology of abattoir wastewater treated by an anaerobic digestor

Wastewater from an anaerobic treatment plant at a slaughterhouse was analysed to determine the bacterial biodiversity present. Molecular analysis of the anaerobic sludge obtained from the treatment plant showed significant diversity, as 27 different phyla were identified. Firmicutes, Proteobacteria, Bacteroidetes, Thermotogae, Euryarchaeota (methanogens), and msbl6 (candidate division) were the dominant phyla of the anaerobic treatment plant and represented 21.7%, 18.5%, 11.5%, 9.4%, 8.9%, and 8.8% of the total bacteria identified, respectively. The dominant bacteria isolated were Clostridium, Bacteroides, Desulfobulbus, Desulfomicrobium, Desulfovibrio and Desulfotomaculum. Our results revealed the presence of new species, genera and families of microorganisms. The most interesting strains were characterised. Three new bacteria involved in anaerobic digestion of abattoir wastewater were published.

Reclassification of Anaerobaculum mobile, Anaerobaculum thermoterrenum, Anaerobaculum hydrogeniformans as Acetomicrobium mobile comb. nov., Acetomicrobium thermoterrenum comb. nov. and Acetomicrobium hydrogeniformans comb. nov., respectively, and emendation of the genus Acetomicrobium

Taking into account their 16S rRNA gene sequences, it appears that Acetomicrobium flavidum and the three species of the genus Anaerobaculum described so far belong to the same phylogenetic clade with high levels (>95 %) of similarity. In this respect, these three Anaerobaculum species should be reclassified within the genus Acetomicrobium, which has priority over the genus Anaerobaculum, which was validated since the genus Acetomicrobium. The DNA G+C content of Acetomicrobium flavidum is 47.1 mol%, which is of the same order as that of the three Anaerobaculum species. All these bacteria have in common iso-C_15 : 0 as their main fatty acid. Based on further phylogenetic, genetic and chemotaxonomic studies, we propose that Anaerobaculum mobile ( = DSM 13181^T = JCM 12221^T), Anaerobaculum thermoterrenum ( = DSM 13490^T = ACM 5076^T) and Anaerobaculum hydrogeniformans ( = DSM 22491^T = ATCC BAA-1850^T) be reclassified as Acetomicrobium mobile comb. nov., Acetomicrobium thermoterrenum comb. nov. and Acetomicrobium hydrogeniformans comb. nov., respectively. The four bacterial species belong to the phylum Synergistetes.

Prokaryotic diversity in a Tunisian hypersaline lake, Chott El Jerid

Prokaryotic diversity was investigated in a Tunisian salt lake, Chott El Jerid, by quantitative real-time PCR, denaturing gradient gel electrophoresis (DGGE) fingerprinting methods targeting the 16S rRNA gene and culture-dependent methods. Two different samples S1-10 and S2-10 were taken from under the salt crust of Chott El Jerid in the dry season. DGGE analysis revealed that bacterial sequences were related to Firmicutes, Proteobacteria, unclassified bacteria, and Deinococcus-Thermus phyla. Anaerobic fermentative and sulfate-reducing bacteria were also detected in this ecosystem. Within the domain archaea, all sequences were affiliated to Euryarchaeota phylum. Quantitative real-time PCR showed that 16S rRNA gene copy numbers of bacteria was 5 × 10(6) DNA copies g(-1) whereas archaea varied between 5 × 10(5) and 10(6) DNA copies g(-1) in these samples. Eight anaerobic halophilic fermentative bacterial strains were isolated and affiliated with the species Halanaerobium alcaliphilum, Halanaerobium saccharolyticum, and Sporohalobacter salinus. These data showed an abundant and diverse microbial community detected in the hypersaline thalassohaline environment of Chott El Jerid.

Reclassification of Acetomicrobium faecale as Caldicoprobacter faecalis comb. nov

Taking into account its phenotypical and genetic characteristics, Acetomicrobium faecale was first recognized as a member of the genus Acetomicrobium, family Bacteroidaceae, order Bacteroidales, phylum Bacteroidetes, with Acetomicrobium flavidum the type species of the genus. However, it was found that A. faecale had 95.8 %, 97.6 % and 98.4 % similarity, respectively, with Caldicoprobacter guelmensis, Caldicoprobacter algeriensis and Caldicoprobacter oshimai and only 82 % similarity with A. flavidum. The DNA G+C content of A. faecale is 45 mol , which is of the same order as the DNA G+C content of the three strains of species of the genus Caldicoprobacter and its main fatty acid is C16 : 0, with its second most prominent fatty acid, iso-C17 : 0, also common to strains of species of the genus Caldicoprobacter. On the basis of further phylogenetic, genetic and chemotaxonomic studies, we propose that A. faecale (type strain DSM 20678T = JCM 30420T) be reclassified as Caldicoprobacter faecalis comb. nov.

Crassaminicella profunda gen. nov., sp. nov., an anaerobic marine bacterium isolated from deep-sea sediments

A novel, anaerobic, chemo-organotrophic bacterium, designated strain Ra1766H(T), was isolated from sediments of the Guaymas basin (Gulf of California, Mexico) taken from a depth of 2002  m. Cells were thin, motile, Gram-stain-positive, flexible rods forming terminal endospores. Strain Ra1766H(T) grew at temperatures of 25-45 °C (optimum 30 °C), pH 6.7-8.1 (optimum 7.5) and in a salinity of 5-60 g l(-1) NaCl (optimum 30 g l(-1)). It was an obligate heterotrophic bacterium fermenting carbohydrates (glucose and mannose) and organic acids (pyruvate and succinate). Casamino acids and amino acids (glutamate, aspartate and glycine) were also fermented. The main end products from glucose fermentation were acetate, butyrate, ethanol, H2 and CO2. Sulfate, sulfite, thiosulfate, elemental sulfur, fumarate, nitrate, nitrite and Fe(III) were not used as terminal electron acceptors. The predominant cellular fatty acids were C14  : 0, C16 : 1ω7, C16 : 1ω7 DMA and C16 : 0. The main polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and phospholipids. The G+C content of the genomic DNA was 33.7 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain Ra1766H(T) was affiliated to cluster XI of the order Clostridiales, phylum Firmicutes. The closest phylogenetic relative of Ra1766H(T) was Geosporobacter subterraneus (94.2% 16S rRNA gene sequence similarity). On the basis of phylogenetic inference and phenotypic properties, strain Ra1766H(T) ( = DSM 27501(T) = JCM 19377(T)) is proposed to be the type strain of a novel species of a novel genus, named Crassaminicella profunda.

Melghiribacillus thermohalophilus gen. nov., sp. nov., a novel filamentous, endospore-forming, thermophilic and halophilic bacterium

A novel filamentous, endospore-forming, thermophilic and moderately halophilic bacterium designated strain Nari2AT was isolated from soil collected from an Algerian salt lake, Chott Melghir. The novel isolate was Gram-staining-positive, aerobic, catalase-negative and oxidase-positive. Optimum growth occurred at 50–55 °C, 7–10 % (w/v) NaCl and pH 7–8. The strain exhibited 95.4, 95.4 and 95.2 % 16S rRNA gene sequence similarity to Thalassobacillus devorans G19.1T, Sediminibacillus halophilus EN8dT and Virgibacillus kekensis YIM-kkny16T, respectively. The major menaquinone was MK-7. The polar lipid profile consisted of phosphatidylglycerol, diphosphatidylglycerol, three unknown phosphoglycolipids and two unknown phospholipids. The predominant cellular fatty acids were iso-C15 : 0 and iso-C17 : 0. The DNA G+C content was 41.9 mol%. Based on the phenotypic, chemotaxonomic and phylogenetic data, strain Nari2AT is considered to represent a novel species of a new genus in the family Bacillaceae , order Bacillales , for which the name Melghiribacillus thermohalophilus gen. nov., sp. nov. is proposed. The type strain of Melghiribacillus thermohalophilus is Nari2AT ( = DSM 25894T = CCUG 62543T).

Characterization of Sporohalobacter salinus sp. nov., an anaerobic, halophilic, fermentative bacterium isolated from a hypersaline lake

Halophilic, obligately anaerobic, Gram-stain-negative bacterial strains were isolated from a sediment sample taken from under the salt crust of El-Jerid hypersaline lake in southern Tunisia by using tryptone or glucose as the substrate. One strain, CEJFT1BT, was characterized phenotypically and phylogenetically. Cells were non-motile, non-spore-forming, short rods. Strain CEJFT1BT was able to grow in the presence of 5–30 % (w/v) NaCl (optimum 20 %) and at 30–60 °C (optimum 45 °C). It grew at pH 5.5–7.8 and the optimum pH for growth was 6.8. The isolate required yeast extract for growth. Substrates utilized by strain CEJFT1BT as the sole carbon source included glucose, fructose, sucrose, pyruvate, Casamino acids and starch. Individual amino acids such as glutamate, lysine, methionine, serine, tyrosine, and amino acid mixtures formed by the Stickland reaction such as alanine-glycine, valine-proline, leucine-proline, isoleucine-proline were also utilized. Products of glucose fermentation were acetate (major product), butyrate, H2 and CO2. The genomic DNA G+C content of strain CEJFT1BT was 32.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CEJFT1BT should be assigned to the genus Sporohalobacter . The sequence similarity between strain CEJFT1BT and Sporohalobacter lortetii was 98.5 %, but DNA–DNA hybridization between the two strains revealed a relatedness value of 56.4 %, indicating that they are not related at the species level. The combination of phylogenetic analysis, DNA–DNA hybridization data, and differences in substrate utilization support the view that strain CEJFT1BT represents a novel species of the genus Sporohalobacter , for which the name Sporohalobacter salinus sp. nov. is proposed. The type strain is CEJFT1BT ( = DSM 26781T = JCM 19279T).

Caldicoprobacter guelmensis sp. nov., a thermophilic, anaerobic, xylanolytic bacterium isolated from a hot spring

A hyperthermophilic anaerobic bacterium, designated D2C22T, was isolated from the hydrothermal hot spring of Guelma in north-east Algeria. The isolate was a Gram-stain-positive, non-sporulating, non-motile rod, appearing singly or in pairs (0.3–0.4×8.0–9.0 µm). Strain D2C22T grew anaerobically at 45–85 °C (optimum 65 °C), at pH 5–9 (optimum pH 6.8) and with 0–20 g NaCl l−1. Strain D2C22T used glucose, galactose, lactose, fructose, ribose, xylose, arabinose, maltose, cellobiose, mannose, melibiose, sucrose, xylan and pyruvate (only in the presence of yeast extract or biotrypticase) as electron donors. The end products from glucose fermentation were acetate, lactate, CO2 and H2. Nitrate, nitrite, thiosulfate, elemental sulfur, sulfate and sulfite were not used as electron acceptors. The predominant cellular fatty acids were iso-C15 : 0 and iso-C17 : 0. The DNA G+C content was 41.6 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain D2C22T was most closely related to Caldicoprobacter oshimai JW/HY-331T, Caldicoprobacter algeriensis TH7C1T and Acetomicrobium faecale DSM 20678T (95.5, 95.5 and 95.3 % 16S rRNA gene sequence similarity, respectively). Based on phenotypic, phylogenetic and chemotaxonomic characteristics, strain D2C22T is proposed to be a representative of a novel species of the genus Caldicoprobacter within the order Clostridiales , for which the name Caldicoprobacter guelmensis sp. nov. is proposed. The type strain is D2C22T ( = DSM 24605T = JCM 17646T).

Desulfotomaculum peckii sp. nov., a moderately thermophilic member of the genus Desulfotomaculum , isolated from an upflow anaerobic filter treating abattoir wastewaters

A novel anaerobic thermophilic sulfate-reducing bacterium designated strain LINDBHT1T was isolated from an anaerobic digester treating abattoir wastewaters in Tunisia. Strain LINDBHT1T 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 LINDBHT1T required salt for growth (1–40 g NaCl l−1), with an optimum of 20–30 g l−1. In the presence of sulfate as terminal electron acceptor, strain LINDBHT1T 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 rRNA gene sequence indicated that strain LINDBHT1T was affiliated to the genus Desulfotomaculum with the type strains of Desulfotomaculum halophilum and Desulfotomaculum alkaliphilum as its closest phylogenetic relatives (about 89 % similarity). This strain represents a novel species of the genus Desulfotomaculum , Desulfotomaculum peckii sp. nov.; the type strain is LINDBHT1T ( = DSM 23769T = JCM 17209T).

Melghirimyces thermohalophilus sp. nov., a thermoactinomycete isolated from an Algerian salt lake

A novel filamentous bacterium, designated Nari11AT, was isolated from soil collected from a salt lake named Chott Melghir, located in north-eastern Algeria. The strain is an aerobic, halophilic, thermotolerant, Gram-stain-positive bacterium, growing at NaCl concentrations between 5 and 20 % (w/v) and at 43–60 °C and pH 5.0–10.0. The major fatty acids were iso-C15 : 0, anteiso-C15 : 0 and iso-C17 : 0. The DNA G+C content was 53.4 mol%. ll-Diaminopimelic acid was the diamino acid of the peptidoglycan. The major menaquinone was MK-7, but MK-6 and MK-8 were also present in trace amounts. The polar lipid profile consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine and three unidentified phospholipids. Results of molecular and phenotypic analyses led to the description of the strain as a novel member to the genus Melghirimyces , family Thermoactinomycetaceae . Strain Nari11AT shows 96.7 % 16S rRNA gene sequence similarity to the type strain of Melghirimyces algeriensis . On the basis of phenotypic, physiological and phylogenetic data, strain Nari11AT ( = DSM 45514T  = CCUG 60050T) represents the type strain of a novel species, for which the name Melghirimyces thermohalophilus sp. nov. is proposed.

Virgibacillus natechei sp. nov., a moderately halophilic bacterium isolated from sediment of a saline lake in southwest of Algeria

A novel, Gram-positive, moderately halophilic bacterium, oxidase- and catalase-positive designated FarD(T) was isolated from sediments of a saline lake located in Taghit, 93 km from Bechar, southwest of Algeria. Cells were rod-shaped, endospore forming, and motile. Growth occurred at 15-40 °C (optimum, 35 °C), pH 6.0-12.0 (optimum, 7.0) and in the presence of 1-20 % NaCl (optimum, 10 %). Strain FarD(T) used glucose, mannitol, melibiose, D-mannose, and 5 ketogluconate. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, and three phospholipids; MK-7 is the predominant menaquinone. The predominant cellular fatty acids were anteiso C15:0, anteiso C17:0, C20:0, and anteiso C19:0. The DNA G+C content was 42.1 mol%. Phylogenetic analysis of the small-subunit ribosomal RNA gene sequence indicated that strain FarD(T) had as its closest relative Virgibacillus salinus (similarity of 96.3 %). Based on phenotypic, phylogenetic, and taxonomic characteristics, strain FarD(T) is proposed as a novel species of the genus Virgibacillus within the order Clostridiales, for which the name V. natechei is proposed. The type strain is FarD(T) (=DSM 25609(T) = CCUG 62224(T)).

Macellibacteroides fermentans gen. nov., sp. nov., a member of the family Porphyromonadaceae isolated from an upflow anaerobic filter treating abattoir wastewaters

A novel obligately anaerobic, non-spore-forming, rod-shaped mesophilic bacterium, which stained Gram-positive but showed the typical cell wall structure of Gram-negative bacteria, was isolated from an upflow anaerobic filter treating abattoir wastewaters in Tunisia. The strain, designated LIND7HT, grew at 20–45 °C (optimum 35–40 °C) and at pH 5.0–8.5 (optimum pH 6.5–7.5). It did not require NaCl for growth, but was able to grow in the presence of up to 2 % NaCl. Sulfate, thiosulfate, elemental sulfur, sulfite, nitrate and nitrite were not used as terminal electron acceptors. Strain LIND7HT used cellobiose, glucose, lactose, mannose, maltose, peptone, rhamnose, raffinose, sucrose and xylose as electron donors. The main fermentation products from glucose metabolism were lactate, acetate, butyrate and isobutyrate. The predominant cellular fatty acids were anteiso-C15 : 0, C15 : 0, C17 : 0 2-OH and a summed feature consisting of C18 : 2ω6,9c and/or anteiso-C18 : 0, and the major menaquinones were MK-9, MK-9(H2) and MK-10. The G+C content of the genomic DNA was 41.4 mol%. Although the closest phylogenetic relatives of strain LIND7HT were Parabacteroides merdae , Parabacteroides goldsteinii and Parabacteroides gordonii , analysis of the hsp60 gene sequence showed that strain LIND7HT was not a member of the genus Parabacteroides . On the basis of phylogenetic inference and phenotypic properties, strain LIND7HT ( = CCUG 60892T = DSM 23697T = JCM 16313T) is proposed as the type strain of a novel species in a new genus within the family Porphyromonadaceae , Macellibacteroides fermentans gen. nov., sp. nov.

Melghirimyces algeriensis gen. nov., sp. nov., a member of the family Thermoactinomycetaceae , isolated from a salt lake

A novel filamentous bacterium, designated NariEXT, was isolated from soil collected from Chott Melghir salt lake, which is located in the south-east of Algeria. The strain was an aerobic, halotolerant, thermotolerant, Gram-positive bacterium that was able to grow in NaCl concentrations up to 21 % (w/v), at 37–60 °C and at pH 5.0–9.5. The major fatty acids were iso- and anteiso-C15 : 0. The DNA G+C content was 47.3 mol%. The major menaquinone was MK-7, but MK-6 and MK-8 were also present. The polar lipid profile consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylmonomethylethanolamine (methyl-PE). Results of molecular and phenotypic analysis led to the description of the strain as a new member of the family Thermoactinomycetaceae . The isolate was distinct from members of recognized genera of this family by morphological, biochemical and chemotaxonomic characteristics. Strain NariEXT showed 16S rRNA gene sequence similarities of 95.38 and 94.28 % with the type strains of Desmospora activa and Kroppenstedtia eburnea , respectively, but differed from both type strains in its sugars, polar lipids and in the presence of methyl-PE. On the basis of physiological and phylogenetic data, strain NariEXT represents a novel species of a new genus of the family Thermoactinomycetaceae for which the name Melghirimyces algeriensis gen. nov., sp. nov. is proposed. The type strain of Melghirimyces algeriensis, the type species of the genus, is NariEXT ( = DSM 45474T = CCUG 59620T).

Characterization of Defluviitalea saccharophila gen. nov., sp. nov., a thermophilic bacterium isolated from an upflow anaerobic filter treating abattoir wastewaters, and proposal of Defluviitaleaceae fam. nov

A novel thermophilic, anaerobic, Gram-stain-positive, terminal-spore-forming bacterium was isolated from an upflow anaerobic filter treating abattoir wastewaters in Tunisia. This strain, designated LIND6LT2T, grew at 40–60 °C (optimum 50–55 °C) and at pH 6.0–8.5 (optimum pH 7.0–7.5). It did not require NaCl for growth, but tolerated it up to 2 %. Sulfate, thiosulfate, elemental sulfur, sulfite, nitrate and nitrite were not used as electron acceptors. Growth of LIND6LT2T was inhibited by sulfite (2 mM). Strain LIND6LT2T used cellobiose, glucose, mannose, maltose, mannitol, sucrose and xylose as electron donors. The main fermentation products from glucose metabolism were acetate, formate, butyrate and isobutyrate. The predominant cellular fatty acids were C16 : 0 (68.4 %) and C14 : 0 (8.3 %). The G+C content of the genomic DNA was 35.2 mol%. On the basis of its phylogenetic and physiological properties, a new genus and species, Defluviitalea saccharophila gen. nov., sp. nov., are proposed to accommodate strain LIND6LT2T, placed in Defluviitaleaceae fam. nov. within the phylum Firmicutes, class Clostridia, order Clostridiales. Strain LIND6LT2T ( = DSM 22681T  = JCM 16312T) is the type strain of Defluviitalea saccharophila, which itself is the type species of Defluviitalea.

Anaerosalibacter bizertensis gen. nov., sp. nov., a halotolerant bacterium isolated from sludge

A strictly anaerobic, halotolerant and thermotolerant strain, designated C5BEL(T), was isolated in north Tunisia from storage tanks holding waste generated by the recycling of discarded motor oils. Cells of strain C5BEL(T) were Gram-stain-positive, motile by laterally inserted flagella, straight, and spore-forming. Their two major fatty acids were iso-C(15 : 0) and iso-C(15 : 0) dimethyl acetal. Growth was observed at temperatures of 25-55 °C (optimum, 40 °C) and at pH 6-9 (optimum, pH 7.5). The salinity range for growth was 0-100 g l(-1) NaCl (optimum, 5 g l(-1)). Yeast extract was required for growth. Strain C5BEL(T) was heterotrophic, able to use glucose, pyruvate, succinate, yeast extract, bio-trypticase and peptone, but unable to grow on Casamino acids. Sulfate, thiosulfate, sulfite, elemental sulfur, fumarate, nitrate and nitrite were not reduced. The DNA G+C content of strain C5BEL(T) was 31.1 mol%. 16S rRNA gene sequence analysis indicated that strain C5BEL(T) was a member of the family Clostridiaceae, class Clostridia, phylum Firmicutes and was most closely related to Sporanaerobacter acetigenes Lup33(T) ( = DSM 13106(T)) (92.4 % similarity). On the basis of 16S rRNA gene sequence comparisons and physiological characteristics, strain C5BEL(T) can be classified as a novel species in a new genus, for which the name Anaerosalibacter bizertensis gen. nov., sp. nov. is proposed. The type strain of the type species is C5BEL(T) ( = DSM 23801(T) = JCM 17239(T)).

Desulfovibrio piezophilus sp. nov., a piezophilic, sulfate-reducing bacterium isolated from wood falls in the Mediterranean Sea

A novel sulfate-reducing bacterium, designated C1TLV30T, was isolated from wood falls at a depth of 1693 m in the Mediterranean Sea. Cells were motile vibrios (2–4×0.5 µm). Strain C1TLV30T grew at temperatures between 15 and 45 °C (optimum 30 °C) and at pH 5.4–8.6 (optimum 7.3). It required NaCl for growth (optimum at 25 g NaCl l−1) and tolerated up to 80 g NaCl l−1. Strain C1TLV30T used as energy sources: lactate, fumarate, formate, malate, pyruvate and ethanol. The end products from lactate oxidation were acetate, H2S and CO2 in the presence of sulfate as terminal electron acceptor. Besides sulfate, thiosulfate and sulfite were also used as terminal electron acceptors, but not elemental sulfur, fumarate, nitrate or nitrite. Strain C1TLV30T possessed desulfoviridin and was piezophilic, growing optimally at 10 MPa (range 0–30 MPa). The membrane lipid composition of this strain was examined to reveal an increase in fatty acid chain lengths at high hydrostatic pressures. The G+C content of the genomic DNA was 49.6 % and the genome size was estimated at 3.5±0.5 Mb. Phylogenetic analysis of the SSU rRNA gene sequence indicated that strain C1TLV30T was affiliated to the genus Desulfovibrio with Desulfovibrio profundus being its closest phylogenetic relative (similarity of 96.4 %). On the basis of SSU rRNA gene sequence comparisons and physiological characteristics, strain C1TLV30T ( = DSM 21447T  = JCM 1548T) is proposed to be assigned to a novel species of the genus Desulfovibrio, Desulfovibrio piezophilus sp. nov.

Caldilinea tarbellica sp. nov., a filamentous, thermophilic, anaerobic bacterium isolated from a deep hot aquifer in the Aquitaine Basin

An anaerobic, thermophilic, filamentous (0.45 × >100 µm) bacterium, designated D1-25-10-4T, was isolated from a deep hot aquifer in France. Cells were non-motile and Gram-negative. Growth was observed at 43–65 °C (optimum 55 °C), at pH 6.8–7.8 (optimum pH 7.0) and with 0–5 g NaCl l−1 (optimum 0 g NaCl l−1). Strain D1-25-10-4T was a chemo-organotroph and fermented ribose, maltose, glucose, galactose, arabinose, fructose, mannose, sucrose, raffinose, xylose, glycerol, fumarate, peptone, starch and xylan. Yeast extract was required for growth. Sulfate, thiosulfate, sulfite, elemental sulfur, nitrate, nitrite and fumarate were not used as terminal electron acceptors. The G+C content of the DNA was 61.9 mol%. The major cellular fatty acids of strain D1-25-10-4T were C17 : 0, C18 : 0, C16 : 0 and iso-C17 : 0. The closest phylogenetic relative of strain D1-25-10-4T was Caldilinea aerophila STL-6-O1T (97.9 % 16S rRNA gene sequence similarity). DNA–DNA relatedness between strain D1-25-10-4T and Caldilinea aerophila DSM 14535T was 8.7±1 %. On the basis of phylogenetic, genotypic and phenotypic characteristics, strain D1-25-10-4T represents a novel species within the genus Caldilinea, class Caldilineae, phylum Chloroflexi, for which the name Caldilinea tarbellica sp. nov. is proposed. The type strain is D1-25-10-4T ( = DSM 22659T  = JCM 16120T).

Sporosalibacterium faouarense gen. nov., sp. nov., a moderately halophilic bacterium isolated from oil-contaminated soil

A novel strictly anaerobic, moderately halophilic and mesophilic bacterium, designated strain SOL3f37T, was isolated from a hydrocarbon-polluted soil surrounding a deep petroleum environment located in south Tunisia. Cells of strain SOL3f37T stained Gram-positive and were motile, straight and spore-forming. Strain SOL3f37T had a typical Gram-positive-type cell-wall structure, unlike the thick, multilayered cell wall of its closest relative Clostridiisalibacter paucivorans. The major fatty acids were iso-C15 : 0 (41 %), iso-C14 : 0 3-OH and/or iso-C15 : 0 dimethyl acetal (21.6 %), iso-C13 : 0 (4.4 %), anteiso-C15 : 0 (3.9 %) and iso-C15 : 1 (2.8 %). Strain SOL3f37T grew between 20 and 48 °C (optimum 40 °C) and at pH 6.2–8.1 (optimum pH 6.9). Strain SOL3f37T required at least 0.5 g NaCl l−1 and grew in the presence of NaCl concentrations up to 150 g l−1 (optimum 40 g l−1). Yeast extract (2 g l−1) was required for degradation of pyruvate, fumarate, fructose, glucose and mannitol. Also, strain SOL3f37T grew heterotrophically on yeast extract, peptone and bio-Trypticase, but was unable to grow on Casamino acids. Sulfate, thiosulfate, sulfite, elemental sulfur, fumarate, nitrate and nitrite were not reduced. The DNA G+C content was 30.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SOL3f37T was a member of the family Clostridiaceae in the order Clostridiales; strain SOL3f37T was related to members of various genera of the family Clostridiaceae. It exhibited highest 16S rRNA gene sequence similarity (93.4 %) with Clostridiisalibacter paucivorans 37HS60T, 91.8 % with Thermohalobacter berrensis CTT3T and 91.7 % with Caloranaerobacter azorensis MV1087T. On the basis of genotypic, phenotypic and phylogenetic data, it is suggested that strain SOL3f37T represents a novel species in a new genus. The name Sporosalibacterium faouarense gen. nov., sp. nov. is proposed, with SOL3f37T (=DSM 21485T =JCM 15487T) as the type strain of Sporosalibacterium faouarense.

Caldicoprobacter algeriensis sp. nov. a new thermophilic anaerobic, xylanolytic bacterium isolated from an Algerian hot spring

A thermophilic anaerobic bacterium (strain TH7C1(T)) was isolated from the hydrothermal hot spring of Guelma in the northeast of Algeria. Strain TH7C1(T) stained Gram-positive, was a non-motile rod appearing singly, in pairs, or as long chains (0.7-1 × 2-6 μm(2)). Spores were never observed. It grew at temperatures between 55 and 75°C (optimum 65°C) and at pH between 6.2 and 8.3 (optimum 6.9). It did not require NaCl for growth, but tolerated it up to 5 g l(-1). Strain TH7C1(T) is an obligatory heterotroph fermenting sugars including glucose, galactose, lactose, raffinose, fructose, ribose, xylose, arabinose, maltose, mannitol, cellobiose, mannose, melibiose, saccharose, but also xylan, and pyruvate. Fermentation of sugars only occurred in the presence of yeast extract (0.1%). The end-products from glucose fermentation were acetate, lactate, ethanol, CO(2), and H(2). Nitrate, nitrite, thiosulfate, elemental sulfur, sulfate, and sulfite were not used as electron acceptors. The G+C content of the genomic DNA was 44.7 mol% (HPLC techniques). Phylogenetic analysis of the small-subunit ribosomal RNA (rRNA) gene sequence indicated that strain TH7C1(T) was affiliated to Firmicutes, order Clostridiales, family Caldicoprobacteraceae, with Caldicoprobacter oshimai (98.5%) being its closest relative. Based on phenotypic, phylogenetic, and genetic characteristics, strain TH7C1(T) is proposed as a novel species of genus Caldicoprobacter, Caldicoprobacter algeriensis, sp. nov. (strain TH7C1(T) = DSM 22661(T) = JCM 16184(T)).

Desulfovibrio legallis sp. nov.: a moderately halophilic, sulfate-reducing bacterium isolated from a wastewater digestor in Tunisia

A new moderately halophilic sulfate-reducing bacterium (strain H₁(T) ) was enriched and isolated from a wastewater digestor in Tunisia. Cells were curved, motile rods (2-3 x 0.5 μm). Strain H₁(T) grew at temperatures between 22 and 43°C (optimum 35°C), and at pH between 5.0 and 9.2 (optimum 7.3-7.5). Strain H₁(T) required salt for growth (1-45 g of NaCl/l), with an optimum at 20-30 g/l. Sulfate, sulfite, thiosulfate, and elemental sulfur were used as terminal electron acceptors but not nitrate and nitrite. Strain H₁(T) utilized lactate, pyruvate, succinate, fumarate, ethanol, and hydrogen (in the presence of acetate and CO₂) as electron donors in the presence of sulfate as electron acceptor. The main end-products from lactate oxidation were acetate with H₂ and CO₂. The G + C content of the genomic DNA was 55%. The predominant fatty acids of strain H₁(T) were C(15:0) iso (38.8%), C(16:0) (19%), and C(14:0) iso 3OH (12.2%), and menaquinone MK-6 was the major respiratory quinone. Phylogenetic analysis of the small-subunit (SSU) ribosomal RNA (rRNA) gene sequence indicated that strain H₁(T) was affiliated to the genus Desulfovibrio. On the basis of SSU rRNA gene sequence comparisons and physiological characteristics, strain H₁(T) is proposed to be assigned to a novel species of sulfate reducers of the genus Desulfovibrio, Desulfovibrio legallis sp. nov. (= DSM 19129(T) = CCUG 54389(T)).

Chryseobacterium solincola sp. nov., isolated from soil

A Gram-staining-negative, yellow-pigmented, strictly aerobic bacterium, designated strain 1YB-R12T, was isolated from a soil sample in western Algeria. The novel isolate was heterotrophic, chemoorganotrophic, halotolerant and psychrotolerant. The temperature and pH optima for growth were 28–30 °C and pH 7.3–8. The bacterium tolerated up to 6 % (w/v) NaCl. Cells were non-motile, non-gliding and non-spore-forming, and were characterized by a variable morphological cycle. Flexirubin-type pigments were not detected. 16S rRNA gene sequence analysis showed that strain 1YB-R12Toccupied a distinct lineage within the genusChryseobacteriumand shared highest sequence similarity withChryseobacterium haifenseLMG 24029T(96.5 %). The DNA G+C content of strain 1YB-R12Twas 40.9 mol%. The predominant cellular fatty acids were anteiso-C15 : 0(41.4 %) and iso-C15 : 0(14.4 %). On the basis of phenotypic properties and phylogenetic distinctiveness, strain 1YB-R12Tis considered to represent a novel species of the genusChryseobacterium, for which the nameChryseobacterium solincolasp. nov. is proposed. The type strain is 1YB-R12T(=DSM 22468T=CCUG 55604T).

First evidence of aerobic biodegradation of BTEX compounds by pure cultures of Marinobacter

Marinobacter vinifirmus was shown to degrade toluene as sole carbon and energy source under aerobiosis and at NaCl concentrations in the range 30-150 g/L. Maximum toluene consumption rate, total CO2, and biomass productions were measured in the presence of 60 g/L of NaCl. Under these conditions, 90% of the carbon from toluene was recovered as CO2 and biomass. Maximum specific toluene consumption rate was about 0.12 mgC toluene mgC biomass(-1) h(-1) at NaCl concentrations between 30 and 60 g/L. It decreased to 0.03 mgC toluene mgC biomass(-1) h(-1) at 150 g/L. Besides toluene, M. vinifirmus degraded benzene, ethylbenzene, and p-xylene. Benzene and toluene were utilized to a lesser extent by another Marinobacter sp., Marinobacter hydrocarbonoclasticus.

Desulfotomaculum hydrothermale sp. nov., a thermophilic sulfate-reducing bacterium isolated from a terrestrial Tunisian hot spring

A novel strictly anaerobic, moderately thermophilic, sulfate-reducing bacterium, designated strain Lam5(T), was isolated from a hot spring in north-east Tunisia and was characterized phenotypically and phylogenetically. The isolate stained Gram-negative but had a Gram-positive-type cell wall. The strain comprised endospore-forming, slightly curved rod-shaped cells with peritrichous flagella. It did not possess desulfoviridin. Strain Lam5(T) grew anaerobically at 40-60 degrees C (optimally at 55 degrees C) and at pH 5.8-8.2 (optimally at pH 7.1); it did not require NaCl but tolerated concentrations up to 1.5 % (w/v). It utilized lactate, pyruvate, formate, ethanol, butanol, glycerol, propanol and H(2) (plus acetate) as electron donors. Lactate was oxidized and pyruvate was fermented to acetate. Sulfate, sulfite, thiosulfate, As(V) and Fe(III) (but not elemental sulfur, fumarate, nitrate or nitrite) were used as electron acceptors. The G+C content of the genomic DNA was 46.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequencing showed that strain Lam5(T) was a member of the genus Desulfotomaculum, with Desulfotomaculum putei as its closest relative (96 % similarity to the type strain). On the basis of genotypic, phenotypic and phylogenetic data, strain Lam5(T) represents a novel species of the genus Desulfotomaculum, for which the name Desulfotomaculum hydrothermale sp. nov. is proposed. The type strain is Lam5(T) (=DSM 18033(T) =JCM 13992(T)).

Biological control of grey mould in strawberry fruits by halophilic bacteria

AIMS

Grey mould caused by Botrytis cinerea is an economically important disease of strawberries in Tunisia and worldwide. The aim of this study was to select effective halophilic bacteria from hypersaline ecosystems and evaluate the abilities of antifungal bacteria to secrete extracellular hydrolytic enzymes, anti-Botrytis metabolites and volatiles.

METHODS AND RESULTS

Grey mould was reduced in strawberry fruits treated with halophilic antagonists and artificially inoculated with B. cinerea. Thirty strains (20.2%) were active against the pathogen and reduced the percentage of fruits infected after 3 days of storage at 20 degrees C, from 50% to 91.66%. The antagonists were characterized by phenotypic tests and 16S rDNA sequencing. They were identified as belonging to one of the species: Virgibacillus marismortui, B. subtilis, B. pumilus, B. licheniformis, Terribacillus halophilus, Halomonas elongata, Planococcus rifietoensis, Staphylococcus equorum and Staphylococcus sp. The effective isolates were tested for antifungal secondary metabolites.

CONCLUSIONS

Moderately halophilic bacteria may be useful in biological control against this pathogen during postharvest storage of strawberries.

SIGNIFICANCE AND IMPACT OF THE STUDY

The use of such bacteria may constitute an important alternative to synthetic fungicides. These moderate halophiles can be exploited in commercial production and application of the effective strains under storage and greenhouse conditions.

Characterization of Halanaerobaculum tunisiense gen. nov., sp. nov., a new halophilic fermentative, strictly anaerobic bacterium isolated from a hypersaline lake in Tunisia

A new halophilic anaerobe was isolated from the hypersaline surface sediments of El-Djerid Chott, Tunisia. The isolate, designated as strain 6SANG, grew at NaCl concentrations ranging from 14 to 30%, with an optimum at 20-22%. Strain 6SANG was a non-spore-forming, non-motile, rod-shaped bacterium, appearing singly, in pairs, or occasionally as long chains (0.7-1 x 4-13 microm) and showed a Gram-negative-like cell wall pattern. It grew optimally at pH values between 7.2 and 7.4, but had a very broad pH range for growth (5.9-8.4). Optimum temperature for growth was 42 degrees C (range 30-50 degrees C). Strain 6SANG required yeast extract for growth on sugars. Glucose, sucrose, galactose, mannose, maltose, cellobiose, pyruvate, and starch were fermented. The end products from glucose fermentation were acetate, butyrate, lactate, H(2), and CO(2). The G + C ratio of the DNA was 34.3 mol%. Strain 6SANG exhibited 16S rRNA gene sequence similarity values of 91-92% with members of the genus Halobacteroides, H. halobius being its closest phylogenetic relative. Based on phenotypic and phylogenetic characteristics, we propose that this bacterium be classified as a novel species of a novel genus, Halanaerobaculum tunisiense gen. nov., sp. nov. The type strain is 6SANG(T) (=DSM 19997(T)=JCM 15060(T)).

Exiguobacterium profundum sp. nov., a moderately thermophilic, lactic acid-producing bacterium isolated from a deep-sea hydrothermal vent

A facultatively anaerobic, halotolerant, moderately thermophilic and non-sporulating bacterium, designated strain 10C(T), was isolated from deep-sea hydrothermal vent samples collected on the 13 degrees N East Pacific Rise at a depth of approximately 2600 m. Cells of strain 10C(T) were Gram-positive, motile rods, and grew optimally at 45 degrees C (range 12-49 degrees C), pH 7.0 (range pH 5.5-9.5) and 0-2 % NaCl (range 0-11 %). (+)-L-Lactate was the main organic acid detected from carbohydrate fermentation with traces of formate, acetate and ethanol. Strain 10C(T) was catalase-positive, oxidase-negative and reduced nitrate to nitrite under anaerobic conditions. The DNA G+C content was 50.4 mol%. Its closest phylogenetic relatives were Exiguobacterium aestuarii TF-16(T) and Exiguobacterium marinum TF-80(T) (16S rRNA gene sequence similarity >99 %). However, strain 10C(T) differed genotypically from these two Exiguobacterium species as indicated by DNA-DNA relatedness data. Therefore, on the basis of phenotypic, genotypic and phylogenetic characteristics, strain 10C(T) is considered to represent a novel species of the genus Exiguobacterium, for which the name Exiguobacterium profundum sp. nov. is proposed. The type strain is 10C(T) (=CCUG 50949(T)=DSM 17289(T)).

Geosporobacter subterraneus gen. nov., sp. nov., a spore-forming bacterium isolated from a deep subsurface aquifer

A novel, strictly anaerobic, chemo-organotrophic bacterium, designated strain VNs68T, was isolated from a well that collected water from a deep aquifer at a depth of 800 m in the Paris Basin, France. Cells were thin, non-motile, Gram-positive rods forming terminal endospores (3.0–5.0×0.5 μm). Strain VNs68T grew at temperatures between 30 and 55 °C (optimum 42 °C) and at pH 5.6–8.4 (optimum pH 7.3). It did not require salt for growth but tolerated up to 40 g NaCl l−1. Strain VNs68T was an obligate heterotroph fermenting carbohydrates such as glucose, xylose, fructose, ribose and cellobiose. Casamino acids and amino acids (arginine, serine, lysine, alanine, aspartate, asparagine, isoleucine, histidine) were also fermented. The main fermentation products from glucose were acetate with H2 and CO2. Sulfate, sulfite, thiosulfate, elemental sulfur, nitrate and nitrite were not used as electron acceptors. The G+C content of the genomic DNA was 42.2 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain VNs68T was affiliated to cluster XI, order Clostridiales, domain Bacteria. On the basis of 16S rRNA gene sequence comparisons and physiological characteristics, strain VNs68T is considered to represent a novel species of a new genus, for which the name Geosporobacter subterraneus gen. nov., sp. nov. is proposed. The type strain of Geosporobacter subterraneus is VNs68T (=DSM 17957T =JCM 14037T).

Tindallia texcoconensis sp. nov., a new haloalkaliphilic bacterium isolated from lake Texcoco, Mexico

A new alkaliphilic and moderately halophilic, strictly anaerobic, fermentative bacterium (strain IMP-300(T)) was isolated from a groundwater sample in the zone of the former soda lake Texcoco in Mexico. Strain IMP-300(T) was Gram-positive, non-sporulated, motile and rod-shaped. It grew within a pH range from 7.5 to 10.5, and an optimum at 9.5. The organism was obligately dependent on the presence of sodium salts. Growth showed an optimum at 35 degrees C with absence of growth above 45 degrees C. It fermented peptone and a few amino acids, preferentially arginine and ornithine, with production of acetate, propionate, and ammonium. Its fatty acid pattern was mainly composed of straight chain saturated, unsaturated, and cyclopropane fatty acids. The G + C content of genomic DNA was 40.0 mol%. Analysis of the 16S rRNA gene sequence indicated that the new isolate belongs to the genus Tindallia, in the low G + C Gram-positive phylum. Phylogenetically, strain IMP-300(T) has Tindallia californiensis, as closest relative with a 97.5% similarity level between their 16S rDNA gene sequences, but the DNA-DNA re-association value between the two DNAs was only 42.2%. On the basis of differences in genotypic, phenotypic, and phylogenetic characteristics, strain IMP-300(T) is proposed as a new species of the genus Tindallia, T. texcoconensis sp. nov. (type strain IMP-300(T ) = DSM 18041(T) = JCM 13990(T)).

Lipolytic activity from Halobacteria: screening and hydrolase production

Strains of Halobacteria from an Algerian culture collection were screened for their lipolytic activity against p-nitrophenyl butyrate (PNPB) and p-nitrophenyl palmitate (PNPP). Most strains were active on both esters and 12% hydrolyzed olive oil. A strain identified as Natronococcus sp. was further studied. It grew optimally at 3.5 M NaCl, pH 8 and 40 degrees C. An increase in temperature shifted the optimum salt concentration range for growth from a wider range of 2-4 M, obtained at 25-30 degrees C, to a narrower range of 3.5-4 M, obtained at 35-40 degrees C. At 45 degrees C the optimum salt concentration was 2 M. These results show a clear correlation between salt and temperature requirement. The optimum conditions for the production of hydrolytic activity during growth were: 3.5 M NaCl and pH 8 for PNPB hydrolytic activity and 4 M NaCl and pH 7.5 for PNPP hydrolytic activity; both at 40 degrees C. The clear supernatant of cells grown at 4 M NaCl showed olive oil hydrolysis activity (in presence of 4 M NaCl) demonstrating the occurrence of a lipase activity in this strain. To our knowledge, this is the first report of a lipase activity at such high salt concentration.

Mahella australiensis gen. nov., sp. nov., a moderately thermophilic anaerobic bacterium isolated from an Australian oil well

A novel Gram-positive, anaerobic and moderately thermophilic bacterium, strain 50-1 BON(T), was isolated from an Australian terrestrial oil reservoir. Cells were spore-forming straight rods, motile by peritrichous flagella. The optimum growth conditions were 50 degrees C, pH 7.5 and 0.1 % NaCl. Strain 50-1 BON(T) fermented arabinose, cellobiose, fructose, galactose, glucose, mannose, sucrose, xylose and yeast extract. Glucose was fermented mainly into lactate, formate, hydrogen and CO(2). The major end product of pyruvate fermentation was acetate together with H(2) and CO(2). Thiosulfate, sulfate, elemental sulfur and nitrate were not used as terminal electron acceptors. The DNA G+C content was 55.5 mol%. The closest phylogenetic relative of strain 50-1 BON(T) was Thermoanaerobacterium thermosulfurigenes (16S rRNA gene sequence similarity of 85.7 %). As strain 50-1 BON(T) was physiologically and phylogenetically different from members of the order 'Thermoanaerobacteriales', it is proposed that strain 50-1 BON(T) (=DSM 15567(T)=CIP 107919(T)) be classified as the type strain of a novel species of a new genus, Mahella australiensis gen. nov., sp. nov.

Desulfatibacillum alkenivorans sp. nov., a novel n-alkene-degrading, sulfate-reducing bacterium, and emended description of the genus Desulfatibacillum

An alkene-degrading, sulfate-reducing bacterium, strain PF2803T, was isolated from oil-polluted sediments (Fos Harbour, France). The cells were found to be Gram-negative, non-sporulating, non-motile and to have a slightly curved rod shape. Optimum growth occurred at 1 % (w/v) NaCl, pH 6.8 and 28-30 degrees C. Strain PF2803T oxidized alkenes (from C8 to C23). The G + C content of the genomic DNA was 57.8 mol% (HPLC). On the basis of 16S rRNA gene sequence analyses, strain PF2803T belongs to the family 'Desulfobacteraceae' in the class 'Deltaproteobacteria', with Desulfatibacillum aliphaticivorans as its closest relative (99.6 % identity). Comparative sequence analyses of the dissimilatory sulfite reductase (dsrAB) gene supported the affiliation of strain PF2803T to the genus Desulfatibacillum. DNA-DNA hybridization with its closest taxon demonstrated 48.4 % similarity. On the basis of the results of physiological and genetic analyses, strain PF2803T is identified as a novel species of the genus Desulfatibacillum, for which the name Desulfatibacillum alkenivorans sp. nov. is proposed. The type strain is PF2803T (= DSM 16219T = ATCC BAA-924T).

Isolation from oil reservoirs of novel thermophilic anaerobes phylogenetically related to Thermoanaerobacter subterraneus: reassignment of T. subterraneus, Thermoanaerobacter yonseiensis, Thermoanaerobacter tengcongensis and Carboxydibrachium pacificum to Caldanaerobacter subterraneus gen. nov., sp. nov., comb. nov. as four novel subspecies

Novel thermophilic, anaerobic, Gram-positive, rod-shaped bacteria, strains SL9 and OCA1, were isolated from oilfields in France and Australia, respectively. Both strains, together with Thermoanaerobacter yonseiensis KB-1(T) (=DSM 13777(T)), Thermoanaerobacter tengcongensis MB4(T) (=DSM 15242(T)) and Carboxydibrachium pacificum JM(T) (=DSM 12653(T)), possessed genomic (DNA-DNA hybridization studies) and phylogenetic similarities with Thermoanaerobacter subterraneus SEBR 7858(T) (=DSM 13054(T)), which was isolated recently from an oilfield reservoir in south-west France. Marked phenotypic differences exist between the three oilfield isolates (T. subterraneus, strain OCA1 and strain SL9): they include temperature range for growth and substrates used. Differences were also observed in the DNA G+C contents of all organisms. Similarly to T. subterraneus, strains SL9 and OCA1, and also T. yonseiensis, T. tengcongensis and Carboxydibrachium pacificum, produced acetate and L-alanine as major end products of glucose metabolism [0.8-1.0 mol L-alanine produced (mol glucose consumed)(-1)] and reduced thiosulfate, but not sulfate, to sulfide. Because of these significant metabolic and phylogenetic differences between the oilfield isolates (T. subterraneus, strain OCA1 and strain SL9), T. yonseiensis, T. tengcongensis and Carboxydibrachium pacificum and other Thermoanaerobacter species, it is proposed to reassign them as a novel genus and species, Caldanaerobacter subterraneus gen. nov., sp. nov., comb. nov., with the creation of four novel subspecies, Caldanaerobacter subterraneus subsp. subterraneus subsp. nov., comb. nov., Caldanaerobacter subterraneus subsp. yonseiensis subsp. nov., comb. nov., Caldanaerobacter subterraneus subsp. tengcongensis subsp. nov., comb. nov. and Caldanaerobacter subterraneus subsp. pacificus subsp. nov., comb. nov.

Petrobacter succinatimandens gen. nov., sp. nov., a moderately thermophilic, nitrate-reducing bacterium isolated from an Australian oil well

A novel Gram-negative, aerobic and moderately thermophilic bacterium, strain 4BONT, was isolated from a non-water-flooded Australian terrestrial oil reservoir. Cells were non-spore-forming straight rods, which were motile by means of a polar flagellum. The optimum growth conditions were 55 °C, pH 6·9 and 0·5 % NaCl. Strain 4BONT was oxidase- and catalase-positive; it grew on fumarate, pyruvate, succinate, formate, ethanol and yeast extract in the presence of oxygen or nitrate as terminal electron acceptor. Nitrate was reduced to nitrous oxide. The DNA G+C content of the strain was 58·6 mol%. The closest phylogenetic relative of strain 4BONT was Hydrogenophilus thermoluteolus (similarity of 91·8 %), of the β-Proteobacteria. As strain 4BONT is physiologically and phylogenetically different from H. thermoluteolus, it is proposed that it be assigned to a novel species of a novel genus, Petrobacter succinatimandens gen. nov., sp. nov. The type strain is 4BONT (=DSM 15512T=CIP 107790T).

Desulfatibacillum aliphaticivorans gen. nov., sp. nov., an n-alkane- and n-alkene-degrading, sulfate-reducing bacterium

A novel marine sulfate-reducing bacterium, strain CV2803T, which is able to oxidize aliphatic hydrocarbons, was isolated from a hydrocarbon-polluted marine sediment (Gulf of Fos, France). The cells were rod-shaped and slightly curved, measuring 0.6x2.2-5.5 microm. Strain CV2803T stained Gram-negative and was non-motile and non-spore-forming. Optimum growth occurred in the presence of 24 g NaCl l(-1), at pH 7.5 and at a temperature between 28 and 35 degrees C. Strain CV2803T oxidized alkanes (from C13 to C18) and alkenes (from C7 to C23). The DNA G+C content was 41.4 mol%. Comparative sequence analyses of the 16S rRNA gene and dissimilatory sulfite reductase (dsrAB) gene and those of other sulfate-reducing bacteria, together with its phenotypic properties, indicated that strain CV2803T was a member of a distinct cluster that contained unnamed species. Therefore, strain CV2803T (=DSM 15576T=ATCC BAA-743T) is proposed as the type strain of a novel species in a new genus, Desulfatibacillum aliphaticivorans gen. nov., sp. nov.

Petrotoga mexicana sp. nov., a novel thermophilic, anaerobic and xylanolytic bacterium isolated from an oil-producing well in the Gulf of Mexico

A novel anaerobic, thermophilic, xylanolytic, motile rod-shaped bacterium with a sheath-like outer structure (toga) was isolated from a Mexican oil well in the Gulf of Mexico. Strain MET12T was a Gram-negative bacterium, reducing elemental sulfur, thiosulfate and sulfite to hydrogen sulfide. Its optimum growth conditions were 55 °C, pH 6·6, 3 % NaCl and 0·15 % MgCl2.6H2O. The DNA G+C content was 36·1 mol%. Phylogenetically, strain MET12T was related to members of genus Petrotoga, with similarities to Petrotoga mobilis, Petrotoga sibirica, Petrotoga miotherma and Petrotoga olearia varying from 97·6 to 98·8 %. However DNA–DNA relatedness values between these species and strain MET12T were lower than 70 %. As strain MET12T (=DSM 14811T=CIP 107371T) was genomically and phenotypically different from existing Petrotoga species, it is proposed as the type strain of a novel species, Petrotoga mexicana sp. nov.

Bosea minatitlanensis sp. nov., a strictly aerobic bacterium isolated from an anaerobic digester

A strictly aerobic, mesophilic bacterium, strain AMX 51(T), was isolated from anaerobic digester sludge. Cells were Gram-negative, motile, non-sporulating, straight to curved rods with one polar flagellum. The isolate had phenotypic traits of the genus Bosea, including cellular fatty acid and substrate utilization profiles. Physiological characteristics and antibiotic susceptibility were determined. Phylogenetic analysis revealed that strain AMX 51(T) was a member of the alpha-Proteobacteria, most closely related to Bosea thiooxidans DSM 9653(T) (similarity of 98.88 %). Methylobacterium organophilum JCM 2833(T), Methylobacterium mesophilicum JCM 2829(T), Afipia clevelandensis DSM 7315(T), Afipia felis DSM 7326(T), Afipia broomeae DSM 7327(T), Blastobacter denitrificans LMG 8443(T) and Bradyrhizobium japonicum DSM 30131(T) showed significant 16S rRNA gene sequence similarities to strain AMX 51(T). The DNA G+C composition of strain AMX 51(T) was 68.5 mol%. DNA-DNA hybridization analysis revealed 44.2 and 15.1 % relatedness between strain AMX 51(T) and the respective type strains of Bosea thiooxidans and A. felis. Overall results suggest that strain AMX 51(T) (=DSM 13099(T)=ATCC 700918(T)=CIP 106457(T)) represents a novel species of the genus Bosea; the name Bosea minatitlanensis sp. nov. is proposed.