Characterization of Microaerobacter geothermalis gen. nov., sp. nov., a novel microaerophilic, nitrate- and nitrite-reducing thermophilic bacterium isolated from a terrestrial hot spring in Tunisia

Eubacterium album sp. nov., a butyrate-producing bacterium isolated from faeces of a healthy human

An oval to rod-shaped, Gram-stain-positive, strictly anaerobic bacterium, designated LFL-14T, was isolated from the faeces of a healthy Chinese woman. Cells of the strain were non-spore-forming, grew optimally at 37 °C (growth range 30-45 °C) and pH 7.0 (growth range 6.0-9.0) under anaerobic conditions in the liquid modified Gifu anaerobic medium (mGAM). The result of 16S rRNA gene-based analysis indicated that LFL-14T shared an identity of 94.7 0% with Eubacterium ventriosum ATCC 27560T, indicating LFL-14T represented a novel taxon. The results of genome-based analysis revealed that the average nucleotide identity (ANI), the digital DNA-DNA hybridisation (dDDH) and average amino acid identity (AAI) between LFL-14T and its phylogenetically closest neighbour, Eubacterium ventriosum ATCC 27560T, were 77.0 %, 24.6 and 70.9 %, respectively, indicating that LFL-14T represents a novel species of the genus Eubacterium. The genome size of LFL-14T was 2.92 Mbp and the DNA G+C content was 33.14 mol%. We analysed the distribution of the genome of LFL-14T in cohorts of healthy individuals, type 2 diabetes patients (T2D) and patients with non-alcoholic fatty liver disease (NAFLD). We found that its abundance was higher in the T2D cohort, but it had a low average abundance of less than 0.2 % in all three cohorts. The percentages of frequency of occurrence in the T2D, healthy and NAFLD cohorts were 48.87 %, 16.72 % and 13.10 % respectively. The major cellular fatty acids of LFL-14T were C16 : 0 (34.4 %), C17 : 0 2-OH (21.4 %) and C14 : 0 (11.7 %). Additionally, the strain contained diphosphatidylglycerol (DPG) and phosphatidylethanolamine (PE), as well as unidentified phospholipids and unidentified glycolipids. The glucose fermentation products of LFL-14T were acetate and butyrate. In summary, On the basis of its chemotaxonomic, phenotypic, phylogenetic and phylogenomic properties, strain LFL-14T (= CGMCC 1.18005T = KCTC 25580T) is identified as representing a novel species of the genus Eubacterium, for which the name Eubacterium album sp. nov. is proposed.

Hyperthermophile diversity microbes in the Calientes geothermal field, Tacna, Peru

Hyperthermophile microorganisms have been discovered worldwide, and several studies regarding biodiversity and the potential biotechnological applications have been reported. In this work, we describe for the first time the diversity of hyperthermophile communities in the Calientes Geothermal Field (CGF) located 4400 m above sea level in Tacna Region, Perú. Three hot springs were monitored and showed a temperature around 84 to 88 °C, for the microbiome analyzed was taken by sampling of sediment and water (pH 7.3-7.6). The hyperthermophile diversity was determined by PCR, DGGE, and DNA sequencing. The sediments analyzed showed a greater diversity than water samples. Sediments showed a more abundant population of bacteria than archaea, with the presence of at least 9 and 5 phylotypes, respectively. Most interestingly, in some taxa of bacteria (Bacillus) and archaea (Haloarcula and Halalkalicoccus), any of operational taxonomic units (OTUs) have not been observed before in hyperthermophile environments. Our results provide insight in the hyperthermophile diversity and reveal the possibility to develop new biotechnological applications based on the kind of environments.

Thermophilic microorganisms involved in the nitrogen cycle in thermal environments: Advances and prospects

Thermophilic microorganisms mediated significant element cycles and material conversion in the early Earth as well as mediating current thermal environments. Over the past few years, versatile microbial communities that drive the nitrogen cycle have been identified in thermal environments. Understanding the microbial-mediated nitrogen cycling processes in these thermal environments has important implications for the cultivation and application of thermal environment microorganisms as well as for exploring the global nitrogen cycle. This work provides a comprehensive review of different thermophilic nitrogen-cycling microorganisms and processes, which are described in detail according to several categories, including nitrogen fixation, nitrification, denitrification, anaerobic ammonium oxidation, and dissimilatory nitrate reduction to ammonium. In particular, we assess the environmental significance and potential applications of thermophilic nitrogen-cycling microorganisms, and highlight knowledge gaps and future research opportunities.

Bacillales: From Taxonomy to Biotechnological and Industrial Perspectives

For a long time, the genus Bacillus has been known and considered among the most applicable genera in several fields. Recent taxonomical developments resulted in the identification of more species in Bacillus-related genera, particularly in the order Bacillales (earlier heterotypic synonym: Caryophanales), with potential application for biotechnological and industrial purposes such as biofuels, bioactive agents, biopolymers, and enzymes. Therefore, a thorough understanding of the taxonomy, growth requirements and physiology, genomics, and metabolic pathways in the highly diverse bacterial order, Bacillales, will facilitate a more robust designing and sustainable production of strain lines relevant to a circular economy. This paper is focused principally on less-known genera and their potential in the order Bacillales for promising applications in the industry and addresses the taxonomical complexities of this order. Moreover, it emphasizes the biotechnological usage of some engineered strains of the order Bacillales. The elucidation of novel taxa, their metabolic pathways, and growth conditions would make it possible to drive industrial processes toward an upgraded functionality based on the microbial nature.

Draft Genome Sequence of Microaerobacter geothermalis Nad S1T, a Microaerophilic Bacterium Isolated from Tenusia Hot Spring

Microaerobacter geothermalis Nad S1^T is a rare Bacillaceae thermophile that grows optimally at 55°C and circumneutral pH. Although strain Nad S1^T was discovered >10 years ago, its genome is yet to be described. The release of the Nad S1^T genome sequence serves as reference genetic information for subsequent use.

Ecology of Bacillaceae

Members of the family Bacillaceae are among the most robust bacteria on Earth, which is mainly due to their ability to form resistant endospores. This trait is believed to be the key factor determining the ecology of these bacteria. However, they also perform fundamental roles in soil ecology (i.e., the cycling of organic matter) and in plant health and growth stimulation (e.g., via suppression of plant pathogens and phosphate solubilization). In this review, we describe the high functional and genetic diversity that is found within the Bacillaceae (a family of low-G+C% Gram-positive spore-forming bacteria), their roles in ecology and in applied sciences related to agriculture. We then pose questions with respect to their ecological behavior, zooming in on the intricate social behavior that is becoming increasingly well characterized for some members of Bacillaceae. Such social behavior, which includes cell-to-cell signaling via quorum sensing or other mechanisms (e.g., the production of extracellular hydrolytic enzymes, toxins, antibiotics and/or surfactants) is a key determinant of their lifestyle and is also believed to drive diversification processes. It is only with a deeper understanding of cell-to-cell interactions that we will be able to understand the ecological and diversification processes of natural populations within the family Bacillaceae. Ultimately, the resulting improvements in understanding will benefit practical efforts to apply representatives of these bacteria in promoting plant growth as well as biological control of plant pathogens.

Fusibacter fontis sp. nov., a sulfur-reducing, anaerobic bacterium isolated from a mesothermic Tunisian spring

Strain KhalAKB1T, a mesophilic, anaerobic, rod-shaped bacterium, was isolated from water collected from a mesothermic Tunisian spring. Cells were Gram-staining-positive rods, occurring singly or in pairs and motile by one lateral flagellum. Strain KhalAKB1T grew at 15–45 °C (optimum 30 °C), at pH 5.5–8.5 (optimum pH 7.0) and in the presence of 0–35 g NaCl l− 1 (optimum 1 g NaCl l− 1). It fermented yeast extract and a wide range of carbohydrates including cellobiose, d-glucose, d-ribose, sucrose, d-xylose, maltose, d-galactose and starch as electron donors. Acetate, ethanol, CO2 and H2 were end products of glucose metabolism. It reduced elemental sulfur, but not sulfate, thiosulfate or sulfite, into sulfide. The DNA G+C content was 37.6 mol%. The predominant cellular fatty acids were C14 : 0 and C16 : 0. Phylogenetic analysis of the 16S rRNA gene sequence suggested Fusibacter bizertensis as the closest relative of this isolate (identity of 97.2 % to the type strain). Based on phenotypic, phylogenetic and genotypic taxonomic characteristics, strain KhalAKB1T is proposed to be assigned to a novel species within the genus Fusibacter, order Clostridiales, Fusibacter fontis sp. nov. The type strain is KhalAKB1T ( = DSM 28450T = JCM 19912T).

Environmental microbiology as a mosaic of explored ecosystems and issues

Microbes are phylogenetically (Archaea, Bacteria, Eukarya, and viruses) and functionally diverse. They colonize highly varied environments and rapidly respond to and evolve as a response to local and global environmental changes, including those induced by pollutants resulting from human activities. This review exemplifies the Microbial Ecology EC2CO consortium's efforts to explore the biology, ecology, diversity, and roles of microbes in aquatic and continental ecosystems.

Novibacillus thermophilus gen. nov., sp. nov., a Gram-staining-negative and moderately thermophilic member of the family Thermoactinomycetaceae

Two Gram-staining-negative, facultatively anaerobic bacterial strains, SG-1T and SG-2, were isolated from a saline soil sample and a compost sample, respectively. The cells were non-motile rods that occurred singly or in chains, and endospores were not observed under tested growth conditions. Optimum growth occurred at 50 °C, pH 7.5–8.0 and with 5–7 % (w/v) NaCl. The DNA G+C content was 49.5–50.5 mol%. The strains contained MK-7 as the predominant menaquinone and iso-C15 : 0 and anteiso-C15 : 0 as the major fatty acids. The polar lipids consisted mainly of diphosphatidylglycerol and phosphatidylglycerol. The cell-wall peptidoglycan type was A1γ (meso-DAP direct). Phylogenetic analyses revealed that the new isolates belonged to the family Thermoactinomycetaceae, exhibiting low 16S rRNA gene sequence similarity (90.8–91.3 %) to the nearest type strain, Mechercharimyces asporophorigenens YM11-542T, and formed a well-supported lineage that was clearly distinguished from all currently described genera in this family. Based on our polyphasic taxonomic characterization, we propose that strains SG-1T and SG-2 represent a novel genus and species within the family Thermoactinomycetaceae, for which we propose the name Novibacillus thermophilus gen. nov., sp. nov. The type strain of Novibacillus thermophilus is SG-1T ( = KCTC 33118T = CGMCC 1.12771T).

Characterization of Desulfovibrio biadhensis sp. nov., isolated from a thermal spring

A novel anaerobic, mesophilic, slightly halophilic sulfate-reducing bacterium, designated strain Khaled BD4T, was isolated from waters of a Tunisian thermal spring. Cells were vibrio-shaped or sigmoids (5–7×1–1.5 µm) and occurred singly or in pairs. Strain Khaled BD4T was Gram-stain-negative, motile and non-sporulated. It grew at 25–45 °C (optimum 37 °C), at pH 5.5–8.3 (optimum pH 7.0) and with 0.5–8 % NaCl (optimum 3 %). It required vitamins or yeast extract for growth. Sulfate, thiosulfate, sulfite and elemental sulfur served as terminal electron acceptors, but not fumarate, nitrate or nitrite. Strain Khaled BD4T utilized H2 in the presence of 2 mM acetate (carbon source), but also lactate, formate, pyruvate and fumarate in the presence of sulfate. Lactate was incompletely oxidized to acetate. Amongst substrates used, only pyruvate was fermented. Desulfoviridin and c-type cytochrome were present. The G+C content of the DNA was 54.6 mol%. The main fatty acids were anteiso-C15 : 0, iso-C18 : 0, iso-C17 : 0 and iso-C14 : 0. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain Khaled BD4T had Desulfovibrio giganteus DSM 4123T (96.7 % similarity) as its closest phylogenetic relative. On the basis of 16S rRNA gene sequence comparisons together with genetic and physiological characteristics, strain Khaled BD4T is assigned to a novel bacterial species, for which the name Desulfovibrio biadhensis sp. nov. is proposed. The type strain is Khaled BD4T ( = DSM 28904T = JCM 30146T).

Fusibacter bizertensis sp. nov., isolated from a corroded kerosene storage tank

Strain LTF Kr01T, 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, northern Tunisia. Cells were Gram-positive-staining rods, occurred singly or in pairs, and were motile by one lateral flagellum. Strain LTF Kr01T grew at temperatures between 15 and 40 °C (optimum 30 °C), between pH 5.5 and 8.2 (optimum pH 7.2) and at NaCl concentrations between 0 and 50 g l−1 (optimum 5 g l−1). It reduced thiosulfate and elemental sulfur into sulfide, but did not reduce sulfate or sulfite. It utilized a wide range of carbohydrates (cellobiose, d-glucose, d-fructose, d-mannitol, d-ribose, sucrose, d-xylose, maltose, d-galactose, starch and trehalose) and produced acetate, CO2 and H2 as end products from glucose fermentation. The DNA G+C content was 37.4 mol%. The predominant cellular fatty acids were C14 : 0 and C16 : 0. Phylogenetic analysis of the 16S rRNA gene sequence suggested that Fusibacter tunisiensis was the closest relative of strain LTF Kr01T (gene sequence similarity of 94.6 %). Based on phenotypic, phylogenetic and genotypic taxonomic characteristics, strain LTF Kr01T is proposed to represent a novel species of the genus Fusibacter , order Clostridiales , for which the name Fusibacter bizertensis sp. nov. is proposed. The type strain is LTF Kr01T ( = DSM 28034T = JCM 19376T).

Vallitalea pronyensis sp. nov., isolated from a marine alkaline hydrothermal chimney

A novel thermotolerant, anaerobic, Gram-stain-positive, spore-forming bacterium was isolated from a hydrothermal chimney in Prony Bay, New Caledonia. This strain, designated FatNI3T, grew at 15–55 °C (optimum 30 °C) and at pH 5.8–8.9 (optimum 7.7). It was slightly halophilic, requiring at least 0.5 % NaCl for growth (optimum 2.5–3.0 %), and was able to grow at up to 6 % NaCl. 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 biotrypticase. The main fermentation products from glucose metabolism were acetate, ethanol, H2 and CO2. The predominant cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0. The main polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, and unknown 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 the type strain of a novel species of the genus Vallitalea , for which the name Vallitalea pronyensis sp. nov. is proposed.

Tepidibacillus fermentans gen. nov., sp. nov.: a moderately thermophilic anaerobic and microaerophilic bacterium from an underground gas storage

A novel moderately thermophilic bacterium, strain STGH(T), was isolated from Severo-Stavropolskoye underground gas storage (Russia). Cells of strain STGH(T) were spore-forming motile straight rods 0.3 μm in diameter and 2.0-4.0 μm in length having a Gram-positive cell wall structure. The temperature range for growth was 36-65 °C, with an optimum at 50-52 °C. The pH range for growth was 5.5-8.0, with an optimum at pH 7.0-7.5. Growth of strain STGH(T) was observed at NaCl concentrations ranging from 0 to 4.0 % (w/v) with an optimum at 1.0 % (w/v). Strain STGH(T) grew anaerobically by reduction of nitrate, thiosulfate, S(0) and AQDS using a number of complex proteinaceous compounds, organic acids and carbohydrates as electron donors. Nitrate was reduced to nitrite; thiosulfate and sulfur were reduced to sulfide. It also was able to ferment pyruvate, glucose, fructose, and maltose. The strain STGH(T) did not grow under aerobic conditions during incubation with atmospheric concentration of oxygen but was able to microaerobic growth (up to 10 % of oxygen in gas phase). The G+C content of DNA of strain STGH(T) was 34.8 mol%. 16S rRNA gene sequence analysis revealed that the isolated organism belongs to the class Bacilli. We propose to assign strain STGH(T) to a new species of a novel genus Tepidibacillus fermentans gen. nov., sp.nov. The type strain is STGH(T) (=DSM 23802(T), =VKM B-2671(T)).

Isolation and characterization of Desulfocurvus thunnarius sp. nov., a sulfate-reducing bacterium isolated from an anaerobic sequencing batch reactor treating cooking wastewater

A novel anaerobic, chemo-organotrophic, sulfate-reducing bacterium, designated strain Olac 40(T), was isolated from a Tunisian wastewater digestor. Cells were curved, motile rods or vibrios (5.0-7.0×0.5 µm). Strain Olac 40(T) grew at temperatures between 15 and 50 °C (optimum 40 °C), and between pH 5.0 and 9.0 (optimum pH 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 40(T) 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 or nitrite. The genomic DNA G+C content of strain Olac 40(T) was 70 mol%. The 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 40(T) was affiliated with the family Desulfovibrionaceae within the class Deltaproteobacteria. On the basis of 16S rRNA gene sequence comparisons and physiological characteristics, strain Olac 40(T) is proposed to be assigned to a novel species of the genus Desulfocurvus, for which the name Desulfocurvus thunnarius is proposed. The type strain is Olac 40(T) ( = DSM 26129(T) = JCM 18546(T)).

Fonticella tunisiensis gen. nov., sp. nov., isolated from a hot spring

A strictly anaerobic, moderately thermophilic, halotolerant rod, designated BELH25T, was isolated from a water sample of a Tunisian hot spring. Cells were non-motile, 2–6 µm long and 0.4–0.6 µm wide, appearing singly or in pairs. The isolate grew at 45–70 °C (optimum 55 °C), at pH 6.2–8.0 (optimum pH 7.0) and with 0–4 % NaCl (optimum 0–2.0 %). Sulfate, thiosulfate, elemental sulfur, sulfite, nitrate and nitrite were not used as terminal electron acceptors. Strain BELH25T used cellobiose, fructose, galactose, glucose, maltose, mannose, sucrose, starch and yeast extract as electron donors. The main fermentation products from glucose metabolism were formate, acetate, ethanol and CO2. The predominant cellular fatty acids were iso-C15 : 0, iso-C17 : 0 and anteiso-C15 : 0. The DNA G+C content was 37.2 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain BELH25T was most closely related to Caloramator viterbiensis JW/MS-VS5T and Fervidicella metallireducens AeBT (92.2 and 92.1 % sequence similarity, respectively), and the isolate was positioned approximately equidistantly between these genera. Based on phenotypic, phylogenetic and chemotaxonomic characteristics, strain BELH25T is proposed to be a member of a novel species of a novel genus within the order Clostridiales , family Clostridiaceae , for which the name Fonticella tunisiensis gen. nov., sp. nov. is proposed. The type strain of the type species is BELH25T ( = DSM 24455T = JCM 17559T).

Defluviitoga tunisiensis gen. nov., sp. nov., a thermophilic bacterium isolated from a mesothermic and anaerobic whey digester

Strain SulfLac1T, a thermophilic, anaerobic and slightly halophilic, rod-shaped bacterium with a sheath-like outer structure (toga), was isolated from a whey digester in Tunisia. The strain’s non-motile cells measured 3–30×1 µm and appeared singly, in pairs or as long chains. The novel strain reduced thiosulfate and elemental sulfur, but not sulfate or sulfite, into sulfide. It grew at 37–65 °C (optimum 55 °C), at pH 6.5–7.9 (optimum pH 6.9) and with 0.2–3 % (w/v) NaCl (optimum 0.5 %). The G+C content of the strain’s genomic DNA was 33.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SulfLac1T was most closely related to Petrotoga mobilis (91.4 % sequence similarity). Based on phenotypic, phylogenetic and chemotaxonomic evidence, strain SulfLac1T represents a novel species of a new genus within the order Thermotogales , for which the name Defluviitoga tunisiensis gen. nov., sp. nov. is proposed. The type strain of the type species is SulfLac1T ( = DSM 23805T  = JCM 17210T).

Fusibacter tunisiensis sp. nov., isolated from an anaerobic reactor used to treat olive-mill wastewater

Strain BELH1(T), a novel mesophilic, anaerobic, halotolerant, rod-shaped bacterium, was isolated from a Tunisian wastewater digester. The cells of the strain are motile, measure 0.5×2-5 µm, and occur singly or in pairs. The strain reduced thiosulfate and elemental sulfur (but not sulfate or sulfite) into sulfide. It grew at 15-40 °C (optimum 30 °C), pH 5.8-8.4 (optimum 7) and with 0-10 % (w/v) NaCl (optimum 3.0 %). The genomic DNA G+C content of strain BELH1(T) was 38.2 mol% and the strain's predominant cellular fatty acids were C(14:0), a summed feature that contained iso-C(17:1) and/or anteiso-C(17:1) B, and C(16:0). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the novel strain was most closely related to Fusibacter paucivorans (94.8 % sequence similarity). Based on phenotypic, phylogenetic and taxonomic characteristics, strain BELH1(T) represents a novel species of the genus Fusibacter, for which the name Fusibacter tunisiensis sp. nov. is proposed. The type strain is BELH1(T) ( = DSM 24436(T) = JCM 17481(T)).

List of new names and new combinations previously effectively, but not validly, published

The purpose of this announcement is to effect the valid publication of the following effectively published new names and new combinations under the procedure described in the Bacteriological Code (1990 Revision). Authors and other individuals wishing to have new names and/or combinations included in future lists should send three copies of the pertinent reprint or photocopies thereof, or an electronic copy of the published paper, to the IJSEM Editorial Office for confirmation that all of the other requirements for valid publication have been met. It is also a requirement of IJSEM and the ICSP that authors of new species, new subspecies and new combinations provide evidence that types are deposited in two recognized culture collections in two different countries. It should be noted that the date of valid publication of these new names and combinations is the date of publication of this list, not the date of the original publication of the names and combinations. The authors of the new names and combinations are as given below, and these authors' names will be included in the author index of the present issue. Inclusion of a name on these lists validates the publication of the name and thereby makes it available in bacteriological nomenclature. The inclusion of a name on this list is not to be construed as taxonomic acceptance of the taxon to which the name is applied. Indeed, some of these names may, in time, be shown to be synonyms, or the organisms may be transferred to another genus, thus necessitating the creation of a new combination.