Qin Lu

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)).

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)).

Ornithinibacillus halotolerans sp. nov., isolated from a saline soil.

A Gram-staining-positive, aerobic, motile, endospore-forming, rod-shaped bacterium, designated GD04T, was isolated from a saline soil sample taken in southern China and was characterized by means of a polyphasic approach. Growth occurred with 0.5-12% (w/v) NaCl (optimum 1-2%) and at pH 7.0-9.5 (optimum pH 8.0) and 10-45 °C (optimum 30 °C). According to the results of a phylogenetic analysis, strain GD04T belonged to the genus Ornithinibacillus, and was related most closely to type strains of the species Ornithinibacillus bavariensis and Ornithinibacillus contaminans (96.5 and 96.5% 16S rRNA gene sequence similarities, respectively). The peptidoglycan amino acid type was A4β, containing L-ornithine and d-aspartic acid. The major respiratory quinone was menaquinone-7 (MK-7). The polar lipid profile of strain GD04T contained predominantly diphosphatidylglycerol with moderate amounts of phosphatidylglycerol, phosphatidylinositol, an unknown phospholipid and an unknown lipid, and a minor amount of another unknown lipid. The G+C content of genomic DNA was 39.3 mol%. The dominant cellular fatty acids were iso-C16:0, iso-C15:0 and anteiso-C15:0. The phenotypic, chemotaxonomic, phylogenetic and genotypic data indicated that strain GD04T represents a novel species of the genus Ornithinibacillus, for which the name Ornithinibacillus halotolerans sp. nov. is proposed. The type strain is GD04T (=KCTC 33116T=CGMCC 1.12408T).

The effects of three commonly used extraction methods on the redox properties of extracellular polymeric substances from activated sludge.

Recently, the redox properties of extracellular polymeric substances (EPS) have attracted the attention of scientists due to their associated environmental significance, such as organic pollutant (e.g. nitroaromatics and substituted nitrobenzenes) degradation and heavy metal (e.g. Cr(VI) and U(VI)) detoxification. Although the separation of EPS from bacterial cells is more often the first step in studies on EPS, and studies have demonstrated that extraction procedures can influence the sorption properties of EPS, few attempts have been made to investigate how separation methods affect the redox properties of the obtained EPS. In this study, three common extraction approaches, that is, centrifugation, formaldehyde+NaOH and ethylene diamine tetra-acetic acid (EDTA), were employed to extract EPS from activated sludge, and the obtained EPS were evaluated for their redox properties using electrochemical means, including cyclic voltammetry and chronoamperometry. In addition, spectroscopic techniques were utilized to explore the structural characteristics and composition of EPS. The results indicated that EPS extracted by EDTA clearly displayed reversible oxidation–reduction peaks in cyclic voltammograms and significantly higher electron-accepting capacity compared with EPS extracted using the other two approaches. Fourier transform infrared spectra and three-dimensional excitation–emission matrix spectra suggested that the EPS extracted with EDTA presented better redox properties because of the effective and efficient extraction of the humic substances, which are important components of the EPS of activated sludge. Therefore, extraction method has an impact on the composition and redox properties of EPS and should be chosen according to research purpose and EPS source.

Ureibacillus defluvii sp. nov., isolated from a thermophilic microbial fuel cell.

A thermophilic bacterium, designated DX-1T, was isolated from the anode biofilm of a microbial fuel cell (MFC). Cells of strain DX-1T were oxidase-positive, catalase-positive and Gram-staining-negative. The strain was found to be rod-shaped and non-motile and to produce subterminal spores. The strain was able to grow with NaCl at concentrations ranging from 0 to 6 %, at temperatures of 25-60 °C (optimum 55 °C) and pH 6.0-8.0 (optimum pH 7.0). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain DX-1T formed a cluster with Ureibacillus thermosphaericus DSM 10633T (96.9% 16S rRNA sequence similarity), Ureibacillus composti DSM 17951T (95.8%), Ureibacillus thermophilus DSM 17952T (95.7%) and Ureibacillus terrenus DSM 12654T (95.3%). The G+C content of the genomic DNA was 40.4 mol%. The major quinone was MK-7, the peptidoglycan type was L-Lys←D-Asp, and the major cellular fatty acids (>5%) were iso-C16:0 and iso-C14:0. The polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol and phospholipids of unknown composition. Based on phenotypic characteristics, chemotaxonomic features and results of phylogenetic analyses, the strain was determined to represent a distinct novel species of the genus Ureibacillus, and the name proposed for the novel species is Ureibacillus defluvii sp. nov., with type strain DX-1T (=CGMCC 1.12358T=KCTC 33127T).