Guiqin Yang

Thauera humireducens sp. nov., a humus-reducing bacterium isolated from a microbial fuel cell.

A Gram-negative, rod-shaped, non-spore-forming bacterium, designated SgZ-1(T), was isolated from the anode biofilm of a microbial fuel cell. The strain had the ability to grow under anaerobic condition via the oxidation of various organic compounds coupled to the reduction of anthraquione-2,6-disulfonate (AQDS) to anthrahydroquinone-2,6-disulfonate (AHQDS). Growth occurred in TSB in the presence of 0-5.5 % (w/v) NaCl (optimum 0-1 %), at 10-45 °C (optimum 25-37 °C) and at pH 6.0-10.0 (optimum 8.0-8.5). Based on 16S rRNA gene sequence similarity, strain SgZ-1(T) belonged to the genus Thauera. The highest level of 16S rRNA gene sequences similarity (96.7 %) was found to be with Thauera aminoaromatica S2(T) and Thauera selenatis AX(T), and lower values were obtained when compared with other recognized Thauera species. Chemotaxonomic analysis revealed that strain SgZ-1(T) contained Q-8 as the predominant quinone, and putrescine and 2-hydroxyputrescine as the major polyamines. The major cellular fatty acids (>5 %) were C16 : 1ω6c and/or C16 : 1ω7c (44.6 %), C16 : 0 (18.8 %), and C18 : 1ω6c and/or C18 : 1ω7c (12.7 %). Based on its phenotypic and phylogenetic properties, chemotaxonomic analysis and the results of physiological and biochemical tests, strain SgZ-1(T) ( = KACC 16524(T) = CCTCC M 2011497(T)) was designated the type strain of a novel species of the genus Thauera, for which the name Thauera humireducens sp. nov. was proposed.

Azospirillum humicireducens sp. nov., a nitrogen-fixing bacterium isolated from a microbial fuel cell.

A Gram-negative, facultative anaerobic, motile, spiral, straight-to-slightly curved rod-shaped and nitrogen-fixing strain, designated SgZ-5(T), was isolated from a microbial fuel cell (MFC) and was characterized by means of a polyphasic approach. Growth occurred with 0-1 % (w/v) NaCl (optimum 1 %) and at pH 5.5-8.5 (optimum pH 7.2) and at 25-37 °C (optimum 30 °C) in nutrient broth (NB). The strain had the ability to grow under anaerobic conditions via the oxidation of various organic compounds coupled to the reduction of anthraquione-2,6-disulfonate (AQDS). Chemotaxonomic characteristics (main ubiquinone Q-10, major fatty acid C18 : 1ω7c/C18 : 1ω6c and DNA G+C content 67.7 mol%) were similar to those of members of the genus Azospirillum. According to the results of phylogenetic analyses, strain SgZ-5(T) belonged to the genus Azospirillum within the family Rhodospirillaceae of the class Alphaproteobacteria, and was related most closely to the type strains of Azospirillum lipoferum, Azospirillum thiophilum and Azospirillum oryzae (98.0, 97.6 and 97.1 % 16S rRNA gene sequence similarity, respectively). DNA-DNA pairing studies showed that the unidentified organism displayed reassociation values of 36.7 ± 3.7, 24.1 ± 2.2 and 22.3 ± 2.4 % to the type strains of A. lipoferum, A. thiophilum and A. oryzae, respectively. Similarities between nifH gene sequences of strain SgZ-5(T) and members of the genus Azospirillum ranged from 94.0 to 97.0 %. A combination of phenotypic, chemotaxonomic, phylogenetic and genotypic data clearly indicated that strain SgZ-5(T) represents a novel species, for which the name Azospirillum humicireducens sp. nov. is proposed. The type strain is SgZ-5(T) ( = CCTCC AB 2012021(T) = KACC 16605(T)).

Fontibacter ferrireducens sp. nov., an Fe(III)-reducing bacterium isolated from a microbial fuel cell.

A novel, dissimilatory Fe(III)-reducing bacterium, designated strain SgZ-2(T), which could couple glucose oxidation to iron reduction for energy conservation, was isolated from a microbial fuel cell. The isolate was Gram-staining-negative, catalase-positive, oxidase-negative and facultatively anaerobic. The strain was able to grow on tryptic soy agar at 15-37 °C and in the presence of 0-5 % (w/v) NaCl. The predominant cellular fatty acids (>5 %) were iso-C15 : 0, iso-C17 : 0 3-OH and iso-C17 : 1ω9c; the major respiratory quinone was MK-7; the major polar lipids were phosphatidylethanolamine, an unidentified aminolipid and three other unidentified lipids; and the DNA G+C content was 55.3 mol%. Phylogenetic analyses based on 16S rRNA sequences showed that the novel strain was most closely related to Fontibacter flavus CC-GZM-130(T) (99.9 % sequence similarity), and was a member of the family Cyclobacteriaceae. The levels of DNA-DNA relatedness observed between strain SgZ-2(T) and F. flavus CCM 7650(T) (<41 %) indicated that the two strains represented two distinct species. Based on phylogenetic analyses and phenotypic characteristics, strain SgZ-2(T) represents a novel species of the genus Fontibacter, for which the name Fontibacter ferrireducens sp. nov. is proposed. The type strain is SgZ-2(T) ( = CCTCC M 2011498(T)  = KACC 16525(T)).

Geobacter soli sp. nov., a dissimilatory Fe(III)-reducing bacterium isolated from forest soil.

A novel Fe(III)-reducing bacterium, designated GSS01(T), was isolated from a forest soil sample using a liquid medium containing acetate and ferrihydrite as electron donor and electron acceptor, respectively. Cells of strain GSS01(T) were strictly anaerobic, Gram-stain-negative, motile, non-spore-forming and slightly curved rod-shaped. Growth occurred at 16-40 °C and optimally at 30 °C. The DNA G+C content was 60.9 mol%. The major respiratory quinone was MK-8. The major fatty acids were C(16:0), C(18:0) and C(16:1)ω7c/C(16:1)ω6c. Strain GSS01(T) was able to grow with ferrihydrite, Fe(III) citrate, Mn(IV), sulfur, nitrate or anthraquinone-2,6-disulfonate, but not with fumarate, as sole electron acceptor when acetate was the sole electron donor. The isolate was able to utilize acetate, ethanol, glucose, lactate, butyrate, pyruvate, benzoate, benzaldehyde, m-cresol and phenol but not toluene, p-cresol, propionate, malate or succinate as sole electron donor when ferrihydrite was the sole electron acceptor. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain GSS01(T) was most closely related to Geobacter sulfurreducens PCA(T) (98.3% sequence similarity) and exhibited low similarities (94.9-91.8%) to the type strains of other species of the genus Geobacter. The DNA-DNA relatedness between strain GSS01(T) and G. sulfurreducens PCA(T) was 41.4 ± 1.1%. On the basis of phylogenetic analysis, phenotypic characterization and physiological tests, strain GSS01(T) is believed to represent a novel species of the genus Geobacter, and the name Geobacter soli sp. nov. is proposed. The type strain is GSS01(T) ( =KCTC 4545(T) =MCCC 1K00269(T)).

Paenibacillus guangzhouensis sp. nov., an Fe(III)- and humus-reducing bacterium from a forest soil.

A Gram-reaction-variable, rod-shaped, motile, facultatively aerobic and endospore-forming bacterium, designated strain GSS02(T), was isolated from a forest soil. Strain GSS02(T) was capable of reducing humic substances and Fe(III) oxides. Strain GSS02(T) grew optimally at 35 °C, at pH 78 and in the presence of 1% NaCl. The predominant menaquinone was MK-7. The major cellular fatty acids were anteiso-C(15:0) and iso-C(16:0) and the polar lipid profile contained mainly phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol, with moderate amounts of two unknown aminophospholipids and a minor amount of one unknown lipid. The DNA G+C content was 53.4 mol%. Comparative 16S rRNA gene sequence analysis showed that strain GSS02(T) was related most closely to Paenibacillus terrigena JCM 21741(T) (98.1% similarity). Mean DNA-DNA relatedness between strain GSS02(T) and P. terrigena JCM 21741(T) was 58.8 ± 0.5%. The phylogenetic, chemotaxonomic and phenotypic results clearly demonstrated that strain GSS02(T) belongs to the genus Paenibacillus and represents a novel species, for which the name Paenibacillus guangzhouensis sp. nov. is proposed. The type strain is GSS02(T) ( =KCTC 33171(T) =CCTCC AB 2013236(T)).

Bacillus composti sp. nov. and Bacillus thermophilus sp. nov., two thermophilic, Fe(III)-reducing bacteria isolated from compost.

Two novel thermophilic bacteria, designated SgZ-9(T) and SgZ-10(T), were isolated from compost. Cells of the two strains were catalase-positive, endospore-forming and Gram-staining-positive rods. Strain SgZ-9(T) was oxidase-positive and non-motile, and strain SgZ-10(T) was oxidase-negative and motile. The highest 16S rRNA gene sequence similarity for both strains SgZ-9(T) and SgZ-10(T) was observed with Bacillus fortis (97.5 % and 96.9 %, respectively). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain SgZ-9(T) formed a cluster with B. fortis R-6514(T) and Bacillus fordii R-7190(T), and SgZ-10(T) formed a cluster with Bacillus farraginis R-6540(T). The DNA-DNA pairing studies showed that SgZ-9(T) displayed 41.6 % and 30.7 % relatedness to the type strains of B. fortis and B. fordii, respectively. The 16S rRNA gene sequence similarity between strains SgZ-9(T) and SgZ-10(T) was 97.2 %, and the level of DNA-DNA relatedness between them was 39.2 %. The DNA G+C content of SgZ-9(T) and SgZ-10(T) was 45.3 and 47.9 mol%, respectively. Chemotaxonomic analysis revealed that both strains contained the menaquinone 7 (MK-7) as the predominant respiratory quinone. The major cellular fatty acids (>5 %) were iso-C15 : 0, anteiso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0 and iso-C17 : 0 in SgZ-9(T) and iso-C15 : 0, anteiso-C15 : 0, iso-C17 : 0, anteiso-C17 : 0 and iso-C16 : 0 in SgZ-10(T). Based on the phenotypic characteristics, chemotaxonomic features, DNA-DNA hybridization with the nearest phylogenetic neighbours and phylogenetic analysis based on the 16S rRNA gene sequences, the two strains were determined to be two distinct novel species in the genus Bacillus, and the names proposed are Bacillus composti sp. nov. SgZ-9(T) ( = CCTCC AB2012109(T) = KACC 16872(T)) and Bacillus thermophilus sp. nov. SgZ-10(T) (CCTCC AB2012110(T) = KACC 16873(T)).

Oceanobacillus luteolus sp. nov., isolated from soil.

Two Gram-stain-positive, rod-shaped and endospore-forming bacteria, designated WM-1T and WM-4, were isolated from a paddy soil and a forest soil, respectively, in South China. Comparative 16S rRNA gene sequence analyses showed that both strains were members of the genus Oceanobacillus and most closely related to Oceanobacillus chironomi LMG 23627T with pairwise sequence similarity of 96.0%. The isolates contained menaquinone-7 (MK-7) as the respiratory quinone and anteiso-C15:0, anteiso-C17:0 and iso-C15:0 as the major fatty acids (>10%). Polar lipids consisted of a predominance of diphosphatidylglycerol and moderate to minor amounts of phosphatidylglycerol and phosphatidylinositol. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The DNA G+C content was 38.6-39.2 mol%. The 16S rRNA gene sequence of strain WM-1T displayed 99.7 % similarity to that of strain WM-4, and DNA-DNA hybridization between the two strains showed a relatedness value of 91 %. Based on the results of this polyphasic study, strains WM-1T and WM-4 represent a novel species in the genus Oceanobacillus, for which the name Oceanobacillus luteolus sp. nov. is proposed. The type strain is WM-1T (=KCTC 33119T=CGMCC 1.12406T).

Bacillus thermocopriae sp. nov., isolated from a compost.

A Gram-reaction-positive, facultatively anaerobic, motile, endospore-forming, rod-shaped strain, designated SgZ-7(T), was isolated from a windrow compost pile and was characterized by means of a polyphasic approach. Growth occurred with 0-3 % (w/v) NaCl (optimum 1 %), at pH 6.0-10.0 (optimum pH 7.2) and at 40-60 °C (optimum 50 °C). The main respiratory quinone was MK-7. The predominant polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The major fatty acids were iso-C15 : 0 and anteiso-C15 : 0. The DNA G+C content was 46.6 mol%. The phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain SgZ-7(T) should be assigned to the genus Bacillus and was related most closely to Bacillus drentensis LMG 21831(T) (sequence similarity 97.2 %). The result of the DNA-DNA hybridization experiment revealed a low relatedness (27.2 %) between the isolate and B. drentensis LMG 21831(T). The results of phenotypic, chemotaxonomic and genotypic analyses clearly indicated that strain SgZ-7(T) represents a novel species, for which the name Bacillus thermocopriae sp. nov. is proposed. The type strain is SgZ-7(T) (= CCTCC AB 2012030(T) = KACC 16700(T)).

Compostibacillus humi gen. nov., sp. nov., a member of the family Bacillaceae, isolated from sludge compost

Two novel Gram-staining-positive, rod-shaped, endospore-forming and moderately thermophilic bacteria, designated strains DX-3(T) and GIESS002, were isolated from sludge composts from Guangdong Province, China. Analysis of 16S rRNA gene sequences revealed that the isolates were closely related to each other with extremely high similarity (99.6 %), and were members of the family Bacillaceae. However, these two isolates formed a novel phylogenetic branch within this family. Their closest relatives were the members of the genera Ornithinibacillus, Oceanobacillus and Virgibacillus. Cells of both strains were facultatively anaerobic and catalase- and oxidase-positive. The cell-wall peptidoglycan type was A1γ (meso-diaminopimelic acid direct). The predominant isoprenoid quinone was MK-7. The main polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The major cellular fatty acid was iso-C15 : 0. The DNA G+C content was 43.2-43.7 mol%. The results of a polyphasic taxonomic study indicated that strains DX-3(T) and GIESS002 represent a novel species in a new genus in the family Bacillaceae, order Bacillales, for which the name Compostibacillus humi gen. nov., sp. nov. is proposed. The type strain is DX-3(T) ( = KCTC 33104(T) = CGMCC 1.12360(T)).

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).