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Two anaerobic, Fe(III)-reducing and Gram-stain-negative strains, designated SG12T and SG195T, were isolated from paddy soils in Fujian Province, PR China. Phylogenetic trees based on 16S rRNA genes and conserved core genes from genomes indicated that strains SG12T and SG195T clustered with members of the genus Geothrix. The two strains showed the highest 16S rRNA sequences similarities to the type strains of ‘Geothrix terrae’ SG184T (98.4–99.6 %), ‘Geothrix alkalitolerans’ SG263T (98.4–99.6 %) and Geothrix fermentans DSM 14018T (98.2–98.8 %). The average nucleotide identity and digital DNA–DNA hybridization values between the two strains and the closely related Geothrix species were 85.1–93.5 % and 29.8–52.9 %, respectively, lower than the cut-off level for prokaryotic species delineation. The menaquinone was MK-8 in both strains. The major fatty acids were iso-C15 : 0, anteiso-C15 : 0 and C16 : 0. Additionally, the two strains possessed iron reduction ability and could utilize organics such as benzene and benzoic acid as electron donors to reduce ferric citrate to ferrous iron. Based on the morphological, biochemical, chemotaxonomic and genome data, the two isolated strains represent two novel species of the genus Geothrix , for which the names Geothrix fuzhouensis sp. nov. and Geothrix paludis sp. nov. are proposed. The type strains are SG12T (=GDMCC 1.3407T=JCM 39330T) and SG195T (= GDMCC 1.3308T=JCM 39327T), respectively.

A strictly anaerobic sulfate-reducing strain, designated SG127T, was isolated from paddy soil. SG127T showed the highest 16S rRNA gene sequence similarity to the type strain of Fundidesulfovibrio magnetotacticus (98.2 %). A phylogenetic tree based on 16S rRNA gene sequences indicated that SG127T clustered with members of the genus Fundidesulfovibrio . Growth of SG127T was observed at 20–37 °C (optimum, 30 °C), pH 5.5–9.0 (optimum, 7.0–8.0) and with 0–0.2 % (w/v) NaCl (optimally without NaCl). SG127T contained MK-7 as the only menaquinone and anteiso-C15 : 0, anteiso-C17 : 1ω9c, C18 : 0, iso-C14 : 0, iso-C15 : 0, iso-C16:0, iso-C16 : 1H, iso-C18 : 1H and summed feature nine as the major fatty acids. The genomic DNA G+C content of SG127T was 64.6 %. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between SG127T and the closely related Fundidesulfovibrio magnetotacticus were 78.5% and 23.2 %, respectively, which were lower than the cut-off values (ANI 95–96% and dDDH 70 %) for prokaryotic species delineation. SG127T had desulfoviridin, possessed nitrogen fixation genes (nifHDK) and actively fixed nitrogen according to the acetylene reduction assay. On the basis of these results, strain SG127T represents a novel species of the genus Fundidesulfovibrio , for which the name Fundidesulfovibrio terrae sp. nov. is proposed. The type strain is SG127T (= GDMCC 1.3137T = JCM 35589T).

Three Gram-positive-staining strains FJAT-49754T, FJAT-49682 and FJAT-49731 were isolated from the citrus rhizosphere soil sample. These strains showed the highest 16S rRNA gene sequence similarity with the type strain of Lederbergia panacisoli (97.8–97.9 %). The 16S rRNA gene sequence similarities between strains FJAT-49754T, FJAT-49682, and FJAT-49731 were 99.9 %. The average nucleotide identity (ANI) values between strains FJAT-49754T, FJAT-49682 and FJAT-49731 were above 96 %, while the ANI values with the members of the genus Lederbergia were below 95 %, which were below the cut-off level for prokaryotic species delineation. The above results suggest that strains FJAT-49754T, FJAT-49682 and FJAT-49731 belong to a novel species of the genus Lederbergia . Growth of strain FJAT-49754T was observed at 10–40 °C (optimum at 30 °C, pH 6.0–10.0 (optimum at pH 8.0), and NaCl tolerance up to 7 % (w/v) (optimum at 1 %). MK-7 was the only menaquinone detected in strain FJAT-49754T, and the main polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The major fatty acids of strain FJAT-49754T were anteiso-C15 : 0, iso-C15 : 0, and C16 : 0. The genomic DNA G+C content of strain FJAT-49754T was 38.7 %. Based on the above results, strain FJAT-49754T represents a novel species of the genus Lederbergia , for which the name Lederbergia citrea sp. nov., is proposed. The type strain is FJAT-49754T (=CCTCC AB 2019211T=LMG 31589T).

A Gram-stain-positive, rod-shaped and motile strain, designated FJAT-49705T, was isolated from the citrus rhizosphere soil sample. Strain FJAT-49705T grew at 20–40 °C (optimum, 30 °C) and pH 6.0–11.0 (optimum, pH 7.0) with 0–5 % (w/v) NaCl (optimum, 2 %). Strain FJAT-49705T showed high 16S rRNA gene sequence similarity to ‘Bacillus dafuensis’ FJAT-25496T (99.7 %) and Cytobacillus solani FJAT-18043T (98.0 %). In phylogenetic (based on 16S rRNA gene sequences) and phylogenomic trees (based on 71 bacterial single-copy genes), strain FJAT-49705T clustered with the members of the genus Cytobacillus . MK-7 was the only isoprenoid quinone present. The main polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and an unidentified phospholipid. The major fatty acids were anteiso-C15 : 0 and iso-C15 : 0. The genomic DNA G+C content was 36.9 %. The average nucleotide identity (ANI) values between FJAT-49705T and ‘B. dafuensis’ FJAT-25496T and C. solani FJAT-18043T were below the cut-off level (95–96 %) recommended as the ANI criterion for interspecies identity. Based on the above results, strain FJAT-49705T represents a novel species of the genus Cytobacillus , for which the name Cytobacillus citreus sp. nov. is proposed. The type strain is FJAT-49705T (=CCTCC AB 2019243T= LMG 31580T).

A strictly anaerobic nitrogen-fixing strain, designated SG106

Two Gram-staining-negative strains, designated SG184

Two Gram-stain positive, rod-shaped, endospore-forming, aerobic, thermophilic strains, designated FJAT-2464T and FJAT-52740, were isolated from the sediment collected from Zhangjiang Estuary Mangrove National Nature Reserve in Fujian Province, China. The 16S rRNA gene sequence similarity between strains FJAT-2464T and FJAT-52740 was 100%. The result suggests that strains FJAT-2464T and FJAT-52740 belong to the same genome species, hence only FJAT-2464T was considered for further analysis. Strain FJAT-2464T showed the highest 16S rRNA gene sequence similarities to the type strains of Neobacillus thermocopriae SgZ-7T (99.9%), Neobacillus cucumis AP-6T (97.6%) and Neobacillus drentensis LMG 21831T (97.5%). Growth was observed at 25–65 °C (optimum 60 °C), pH 7.0–8.0 (optimum 8.0) with NaCl tolerance up to 1.0% (w/v) (optimum without NaCl %). The cell-wall peptidoglycan contained meso-diaminopimelic acid and MK-7 was the only respiratory quinone. The major fatty acids were iso-C15:0 and anteiso-C15:0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified aminophospholipid and unidentified lipids. The average nucleotide identity and digital DNA-DNA hybridization values between strain FJAT-2464T and the most closely related strain N. thermocopriae SgZ-7T was below the threshold value for species delineation. Based on the above results, strain FJAT-2464T represents a novel species of the genus Neobacillus, for which the name Neobacillus sedimentimangrovi sp. nov. is proposed. The type strain is FJAT-2464T (= MCCC 1K04406T = KCTC 43264T).

Mangroves are located at the interface of terrestrial and marine environments, and experience fluctuating conditions, creating a need to better explore the relative role of the bacterial community. Bacillus has been reported to be the dominant group in the mangrove ecosystem and plays a key role in maintaining the biodiversity and function of the mangrove ecosystem. However, studies on bacterial and Bacillus community across four seasons in the mangrove ecosystem are scarce. Here, we employed seasonal large-scale sediment samples collected from the mangrove ecosystem in southeastern China and utilized 16S rRNA gene amplicon sequencing to reveal bacterial and Bacillus community structure changes across seasons. Compared with the whole bacterial community, we found that Bacillus community was greatly affected by season (temperature) rather than site. The key factors, NO

Five strictly anaerobic strains, designated RG2

Two strictly anaerobic nitrogen-fixing strains, designated RG17

Biodegradation is the most sustainable treatment method for waste polystyrene (PS). Thermophiles possess highly efficient biotransformation capabilities that could enhance the biodegradation efficiency of organic solid wastes. However, detailed research on the degradation of PS plastics by thermophile is scarce. Here, the degradation performance of a strain of

The spread of antibiotic resistance has become a serious threat to global public health. Recently, several studies have found that non-antibiotic chemicals can promote the generation and spread of bacterial antibiotic resistance. However, the effects of herbicides on the antibiotic resistance of bacteria remain unclear. In this study

Environmental selection of antibiotic resistance genes (ARGs) is considered to be caused by antibiotic or metal residues, frequently used in livestock. In this study we examined three commercial poultry farms to correlate the co-occurrence patterns of antibiotic and metal residues to the presence of ARGs. We quantified 283 ARGs, 12 mobile genetic elements (MGEs), 49 targeted antibiotics, 7 heavy metals and sequenced 16S rRNA genes. The abundance and type of ARG were significantly enriched in manure while soil harbored the most diverse bacterial community. Procrustes analysis displayed significant correlations between ARGs/MGEs and the microbiome. Cadmium (Cd), arsenic (As), zinc (Zn), copper (Cu) and lead (Pb) were responsible for a majority of positive correlations to ARGs when compared to antibiotics. Integrons and transposons co-occurred with ARGs corresponding to 9 classes of antibiotics, especially Class1 integrase intI-1LC. Redundancy analysis (RDA) and Variance partitioning analysis (VPA) showed that antibiotics, metals, MGEs and bacteria explain solely 0.7%, 5.7%, 12.4%, and 21.9% of variances of ARGs in the microbial community, respectively. These results suggested that bacterial composition and horizontal gene transfer were the major factors shaping the composition of ARGs; Metals had a bigger effect on ARG profile than detected antibiotics in this study.

In order to achieve the high value production of methane, this paper investigated the effect and mechanism of hematite on the inhibitation of the formation of hydrogen sulfide during the anaerobic digestion of high-concentration sulfate wastewater. Different dosages of hematite were added to artificially prepared sulfate wastewater to analyze the migration and transformation pathways of sulfur in the reaction system. The results showed that the delay time of the anaerobic digestion process and the hydrogen sulfide concentration in the control reactor were 1.64 times and 180 times those in the reactor with the optimal hematite dosage of 0.5 g·(30 mL)

Biochar is a charred carbonaceous material that has recently been identified to provide many potential environmental and agricultural applications. Biochar amendments are shown to effectively improve the quality of soil and increase soil microbial biomass. However, the interactions between biochar and microorganisms and the mechanisms through which biochar influences soil microbial growth and activities remain unclear. In this study, we investigated the potential for biochar to function as an electron acceptor for microbial extracellular respiration and growth. Anaerobic incubation of Geobacter sulfurreducens revealed that biochar was used as a sole terminal electron acceptor, as evidenced by a 31-fold increase of biomass and gradual increase in reducing equivalents of biochar and the consumption of acetate after 15 d. An electron stoichiometry analysis showed that 58.7% of the electrons released from acetate oxidation could be recovered in biochar, which was comparable to that of humic substances...

Considering that heavy metal pollution problem is widespread in the soil of South China, bioleaching process and bioleaching combined with Fenton-like reaction were used to study the removal performance of Cu, Zn, Cd and Pb in the contaminated soil around the lead-zinc mine in ShaoGuan City, Guangdong Province, China. Sequential chemical extraction was applied to analyze the effects of different treatments on the fracion distributions of Cu, Zn, Cd and Pb. The results showed that 66.5% of copper,55.1% of zinc, 72.8% of cadmium and 35.6% of lead could be removed after 12-day bioleaching process, among which, the inorganic bound-fracion had the best dissolution efficiency. The rest of the heavy metals in solid phase mainly existed in the form of stabilized residual fraction. With an optimal H

With the aim to investigate the main pollution characteristics of exhaust gases emitted from plastic waste recycling granulation plants, mainly volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs) were analyzed in Xingtan Town, the largest distribution center of plastic waste recycling in China. Both inside and outside the plants, the total concentrations of volatile monocyclic aromatic hydrocarbons (MAHs), PAHs and PAEs ranged from 2000 to 3000 μg m−3, 450 to 1200 ng m−3, and 200 to 1200 ng m−3, respectively. Their concentration levels inside the plants were higher than those outside the plants, and PAHs and PAEs were mainly distributed in the gas-phase. Notably, highly toxic benzo[a]pyrene (BaP) could be detected inside the plants, and harmful PAEs could be detected not only inside but also outside the plants, although PAEs are non-volatile. The exhaust gas composition and concentration were related to the plastic feedstock and granulation temperature.

The bacterial isolate Paracoccus sp. strain FLN-7 hydrolyzes amide pesticides such as diflubenzuron, propanil, chlorpropham, and dimethoate through amide bond cleavage. A gene, ampA , encoding a novel arylamidase that catalyzes the amide bond cleavage in the amide pesticides was cloned from the strain. ampA contains a 1,395-bp open reading frame that encodes a 465-amino-acid protein. AmpA was expressed in Escherichia coli BL21 and homogenously purified using Ni-nitrilotriacetic acid affinity chromatography. AmpA is a homodimer with an isoelectric point of 5.4. AmpA displays maximum enzymatic activity at 40°C and a pH of between 7.5 and 8.0, and it is very stable at pHs ranging from 5.5 to 10.0 and at temperatures up to 50°C. AmpA efficiently hydrolyzes a variety of secondary amine compounds such as propanil, 4-acetaminophenol, propham, chlorpropham, dimethoate, and omethoate. The most suitable substrate is propanil, with K m and k cat values of 29.5 μM and 49.2 s −1 , respectively. The benzoylurea insecticides (diflubenzuron and hexaflumuron) are also hydrolyzed but at low efficiencies. No cofactor is needed for the hydrolysis activity. AmpA shares low identities with reported arylamidases (less than 23%), forms a distinct lineage from closely related arylamidases in the phylogenetic tree, and has different biochemical characteristics and catalytic kinetics with related arylamidases. The results in the present study suggest that AmpA is a good candidate for the study of the mechanism for amide pesticide hydrolysis, genetic engineering of amide herbicide-resistant crops, and bioremediation of amide pesticide-contaminated environments.

Pyrolytic conversion of sewage sludge to biochar, oil and gas is an environmentally and economically acceptable way comparable to conventional options for sewage sludge disposal. The aim of this paper is to investigate the influence of pyrolysis temperature on production of biochar fraction for agronomic application, oil and gas fractions for energy utilization. Sewage sludge samples collected from an urban sewage treatment plant were pyrolysed in a bench–scale quartz tubular furnace over the temperature range of 300-700°C.The results indicated that the biochar fraction yield decreased, the yields of liquid (oil and water) fraction and gas fraction increased by evaluating the pyrolysis temperature. Concentration of heavy metals and nutrient elements present in biochar varied with pyrolysis temperature, the heating value of oil from liquid fraction fluctuated between 26938.3 and 30757.9kJ/kg, the heating value of gas fraction increased from 4012kJ/Nm3 to 12077 kJ/Nm3 with the increasing pyrolysis temperature.

The recovery of Bacillus thuringiensis (Bt) based biopesticides from fermented sludge broth via cross-flow microfiltration (CFMF) was evaluated. Three types of microfiltration membranes, WX-model cellulose, cellulose acetate, and polyethersulfone, were tested for their permeate flux and restoration capacity. The cellulose acetate membrane with a pore size of 0.8 μm was selected for further process optimization and modeling of CFMF. Under optimal conditions, the permeate flux could be greater than 20 l/m2/h if the retentate contained was less than 100 g/l. The spore and crystal proteins recoveries were found to be 99 and 95%, respectively. The standard hydraulic resistance-in-series model was used to determine the parameters of CFMF of Bt fermented sludge. The results demonstrated that CFMF was effective for Bt based biopesticide recovery from fermented sludge.

Microbial fuel cells (MFCs) represent a new method for simultaneous wastewater treatment and biological electricity generation. In this study, an air-cathode MFC with membrane electrode assembly was operated over four batch cycles (a total period of 140 d) and results indicated that starch processing wastewater containing 4852 mg/l of chemical oxygen demand could be used as substrate to produce electricity with this MFC. Maximum voltage output and power density of 490.8 mV and 239.4 mW/m2 (a current density of 893.3 mA/m2) were approached in the third cycle, which also had the minimum internal resistance of about 120 Ω and maximum coulombic efficiency of 8.0%. Removal efficiencies of chemical oxygen demand and ammonia-nitrogen increased as a function of time, and maximum amounted to 98.0% and 90.6%, respectively. Scanning electron microscope image revealed that short rod shaped bacillus were the dominant bacteria on the biofilm of the anode, whose electrochemical activity was proved by cyclic voltammetry. These results demonstrate that starch processing wastewater can be used for power generation in MFCs and also can be treated with high removal efficiencies of chemical oxygen demand and ammonia-nitrogen.

Production of Bacillus thuringiensis (Bt) based bioinsecticide was studied by using starch processing wastewater (SPW) as a raw material. Results indicated that the nutrients contained in SPW were sufficient for growth, sporulation and δ-endotoxin production of Bacillus thuringiensis subsp. kurstaki (Btk). The final cell counts and spore counts achieved in SPW medium were 72% and 107% respectively higher than those in the soybean meal based commercial medium. Higher δ-endotoxin yield of 2.67 mg mL−1 and higher entomotoxicity of 1,050 IU μL−1 were also obtained in SPW medium as compared with the commercial medium at the end of fermentation. The morphological observations also revealed that the fermentation cycle of Btk could be shortened in this new medium. This process provides solutions for safe SPW disposal and production of high potency and low cost bioinsecticide.

Sewage sludge is a cost-effective media for the production of Bacillus thuringiensis (Bt) based biopesticides. To enhance the entomotoxicity of the fermentation broth, pretreatments of sewage sludge by alkali and ultrasonic were applied in this study. Effects of alkaline and ultrasonic pretreatments on the soluble COD (SCOD) and total COD (TCOD) were evaluated by altering the alkali addition dose and the ultrasonic specific energy. Suitable pretreatment conditions were optimized with 5 g l−1 sodium hydroxide (NaOH) for alkaline treatment and 1.2 × 105 kJ kg−1 of total solid for ultrasonic treatment. Fermentations of raw and pretreated sludge for biopesticides were carried out in a bench scale fermentor. Results revealed that both pretreatments were effective for Bt growth and metabolism. Higher viable cells (VC) and viable spores (VS) counts, δ-endotoxin yields and entomotoxicity were achieved in the pretreated sludge. The enhancement was attributed to more available nutrients and better oxygen transfer. Moreover, ultrasonic pretreated sludge was superior to alkaline pretreated sludge for δ-endotoxin production and entomotoxicity owing to its higher soluble C/N ratio and finer particles.

Bioleaching of Cr(III) from tannery sludge using the mixture of ingenuous iron-and sulfur-oxidizing bacteria was investigated in batch flasks. Experiments involved the adaptation of indigenous iron- and sulfur-oxidizing bacteria, the pre-acidification the sludge to pH 6.0 and the addition of energy substrates. Results showed the inoculation of mixture of ingenuous iron- and sulfur-oxidizing bacteria and co-addition of Fe2+ and elemental sulfur accelerated acid production and increase of oxidation-reduction potential originating from the bio-oxidation of Fe2+ and elemental sulfur. Dissolved Cr concentration increased concomitant with pH decreased in the sludge and reached its maximum removal of 95.6%. The amelioration of the odor of bioleached sludge could be noted. However, 20.4% of N, 24.5% of P and 14.3% of organic matter were lost in the bioleaching process. The residual Cr content in the leached tannery sludge was acceptable for use in agriculture. This study had shown the feasibility of applying the bioleaching process, developed for sewage sludge, to tannery sludge with high Cr.

Humus and Fe(III) respiration are important extracellular respiration metabolism. Electron transport pathway is the key issue of extracellular respiration. To understand the electron transport properties and the environmental behavior of a novel Fe(III)- reducing bacterium, Fontibacter sp. SgZ-2, capacities of anaerobic humus/Fe(III) reduction and electron transport mechanisms with four electron acceptors were investigated in this study. The results of anaerobic batch experiments indicated that strain SgZ-2 had the ability to reduce humus analog [ 9,10-anthraquinone-2,6-disulfonic acid (AQDS) and 9,10-anthraquinone-2-sulfonic acid (AQS)], humic acids (HA), soluble Fe(III) (Fe-EDTA and Fe-citrate) and Fe(III) oxides [hydrous ferric oxide (HFO)]. Fermentative sugars (glucose and sucrose) were the most effective electron donors in the humus/Fe(III) reduction by strain SgZ-2. Additionally, differences of electron carrier participating in the process of electron transport with different electron acceptors (i. e. , oxygen, AQS, Fe-EDTA and HFO) were investigated using respiratory inhibitors. The results suggested that similar respiratory chain components were involved in the reducing process of oxygen and Fe-EDTA, including dehydrogenase, quinones and cytochromes b-c. In comparison, only dehydrogenase was found to participate in the reduction of AQS and HFO. In conclusion, different electron transport pathways may be employed by strain SgZ-2 between insoluble and soluble electron acceptors or among soluble electron acceptors. Preliminary models of electron transport pathway with four electron acceptors were proposed for strain SgZ-2, and the study of electron transport mechanism was explored to the genus Fontibacter. All the results from this study are expected to help understand the electron transport properties and the environmental behavior of the genus Fontibacter.

This study investigated the effects of iron oxides with different crystallinities, ferrihydrite (SF) and hematite (SH), on the methane emission in paddy soil of South China under different water conditions, alternative drying/wetting cycles (DW) and continuous flooding (CF). The rates of methane emission, methane production potential and concentrations of Fe(II) and Fe(III) were determined. Results showed that compared with CF, the average methane emission rate was greatly inhibited by DW over 61%, and the addition of iron oxides reduced methane emission rates by 53%. Under the circumstance of DW and iron oxides addition, the combined inhibition effect on the average methane emission (65%-94%) and methane production potential (57%-93%) was significantly higher than the single effect caused by DW or iron oxides. Interestingly, DW coupling poorly crystalline ferrihydrite (SF-DW, 94%) posed a more significantly inhibitory effect on the methane emission than coupling crystalline hematite (SH-DW, 65%). Statistical analysis showed that there was a significantly negative correlation between the Fe(III) concentrations and the methane emission rates (R2 = -0.98, P0.01). Experimental results showed that DW facilitated the cyclic regeneration of Fe(III), and the Fe(III)/Fe(II) cycle in poorly crystalline ferrihydrite was more susceptible to DW than hematite. This study suggested that alternative drying/wetting cycles can remarkably enhance the inhibitory effect of iron oxides on methane emission from paddy soil, and the coupled suppression effect of DW and poorly crystalline ferrihydrite is more obvious than the coupled effect of DW and crystalline hematite.

A Gram positive, thermophilic, and filamentous bacterium, designated strain GIESS004(T), was isolated from a sludge compost from Guangzhou, China. Growth occurred at 45-55 °C (optimum 50-53 °C) and pH 6.0-10.0 (optimum pH 7.0-7.5). The organism formed cream-yellow colonies with radial wrinkles. Aerial mycelium was not produced in any of the growth media tested. Single spores were produced along the substrate hyphae. Strain GIESS004(T) contained MK-7 as the predominant menaquinone and iso-C(16:0), iso-C(15:0) and iso-C(17:0) as the major cellular fatty acids. The cell wall contained meso-diaminopimelic acid. The DNA G+C content was 60.7 mol%. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain GIESS004(T) was associated with the genus Planifilum and formed a cluster with its closest relative of Planifilum composti P8(T) (99.5 % similarity). However, the DNA-DNA pairing study showed that the isolate displayed reassociation value of only 57.6 ± 2.3 % with P. composti P8(T). On the basis of the polyphasic taxonomic results, strain GIESS004(T) (= CCTCC AB2013107(T) = MCCC 1K00414(T)) is designated as the type strain of a novel species of the genus Planifilum, for which the name Planifilum caeni sp. nov. is proposed.

A halophilic, aerobic bacterium, designated GD01(T), was isolated from a mangrove forest soil near the South China Sea. Cells of strain GD01(T) were Gram staining positive, oxidase positive, and catalase positive. The strain was rod shaped and motile by means of peritrichous flagella and produced ellipsoidal endospores. The strain was able to grow with NaCl at concentrations of 0.5-12 % (optimum 3-5 %, w/v), at temperatures of 20-50 °C (optimum 30 °C), and at pH 6.0-8.5 (optimum pH 7.0). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain GD01(T) formed a cluster with O. profundus DSM 18246(T) (96.4 % 16S rRNA gene sequence similarity), O. caeni KCTC 13061(T) (95.4 %), and O. oncorhynchi JCM 12661(T) (94.5 %). The G+C content of strain GD01(T) was 38.7 mol%. The major respiratory quinone was MK-7. The major cellular fatty acids (5 %) were anteiso-C15:0, iso-C16:0 (13.7 %), anteiso-C17:0 (12.6 %), iso-C15:0 (9.9 %), iso-C14:0 (9.5 %), and C16:0 (5.0 %). The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, glycolipid, four unknown lipids, and four unknown phospholipids. Based on phenotypic characteristics, chemotaxonomic features, and phylogenetic analysis based on 16S rRNA gene sequences, the strain was identified to represent a distinct novel species in the genus Oceanobacillus, and the name proposed is Oceanobacillus halophilum sp. nov. with type train GD01(T) (=CCTCC AB 2012863(T) = KCTC 33101(T)).

A Gram-positive, facultative anaerobic, motile, endospore-forming rod strain, designated DX-4(T), was isolated from an electrochemically active biofilm. Growth occurred at 30-65 °C (optimum 55 °C), at pH 6.0-8.5 (optimum pH 7.0-7.5) and with6 % (w/v) NaCl. Cells were catalase- and oxidase-positive. The main respiratory quinone was MK-7, the predominant polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol mannoside, and unidentified aminophospholipid, the DNA G+C content was 38.6 mol% and the major fatty acids (5 %) were iso-C15:0 (38.9 %), iso-C17:0 (30.5 %), iso-C16:0 (5.6 %), and anteiso-C17:0 (5.2 %). The phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain DX-4(T) is a member of the genus Bacillus. The results of phenotypic, chemotaxonomic, and genotypic analyses clearly indicated that strain DX-4(T) represents a novel species, for which the name Bacillus borbori sp. nov. is proposed. The type strain is DX-4(T) (= CCTCC AB2012196(T) = KCTC 33103(T)).

With the use of an alkaliphilic bacterium, Corynebacterium humireducens MFC-5, this study investigated the reduction of goethite (α-FeOOH) and degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) mediated by different humic substances (humics) and quinones in alkaline conditions (pH of 9.0). The results indicated that (i) using sucrose as the electron donor, the strain MFC-5 was capable of reducing anthraquinone-2,6-disulfonic acid (AQDS), anthraquinone-2-disulfonic acid (AQS), anthraquinone-2-carboxylic acid (AQC), humic acid (HA) and fulvic acid (FA), and its reducing capability ranked as AQC > AQS > AQDS > FA > HA; (ii) the anaerobic reduction of α-FeOOH and 2,4-D by the strain was insignificant, while the reductions were greatly enhanced by the addition of quinones/humics serving as redox mediators; (iii) the Fe(III) reduction rate was positively related to the content of quinone functional groups and the electron-accepting capacities (EAC) of quinones/humics based on fourier-transform infrared spectroscopy (FT-IR) and electrochemical analyses; however, such a relationship was not found in 2,4-D degradation probably because quinone reduction was not the rate-limiting step of quinone-mediated reduction of 2,4-D. Using the example of α-FeOOH and 2,4-D, this study well demonstrated the important role of humics reduction on the Fe(III)/Fe(II) biogeochemical cycle and chlorinated organic compounds degradation in alkaline reducing environments. Funding Information This study was supported by the National Natural Science Foundation of China (Nos 41101211, 31070460, 41101477), and The Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.

The principle of the detector is based on the effect of microbial toxicity of water sample on the electricity generation in microbial fuel cell (MFC). The performance of the MFC-type biotoxicity detector was evaluated with the synthetic water containing heavy metals of Cd2+ and Cu2+. The experimental results demonstrated that: (1) relative to the conventional methods, the MFC-type detector is easy to operate, and suitable for on-line measurements with high sensitivity; (2) it only requires 4 h to complete measurements, and can get ready for next measurement within 4 h; (3) there is a significant linear correlation between the concentration of toxic metal(s) and inhibition ratios in Coulombic yields of MFC. As the IC20 (concentration causing 20% inhibition) of Cd2+, Cu2+ and mixed metals (Cd2+ and Cu2+) were 0.6, 0.8 and 0.25 mg/L, the regression coefficients were shown to be 0.9960, 0.9744 and 0.9907.

A strain of humic substance- and Fe(III)- reducing bacterium was isolated from the subterranean forest sediment and designated as MFC-3. The strain is facultative anaerobic, Gram-negative, motile and rod (1.0-3.0 microm long, 0.5-1.0 microm wide) and identified as Pantoea agglomerans with the 16S rDNA sequence analyses. Batch experiments were conducted to investigate its humic substance-and Fe(III)-respiring activity. The results showed that MFC-3 was capable of anaerobic respiration on anthraquinone-2,6-disulphonate (AQDS) as the sole terminal electron acceptor with glucose as the electron donor. Within 48 h, MFC-3 could reduce 0.3 mmol x L(-1) AQDS at the expense of 4.5 mmol x L(-1) glucose, and the population of bacteria was increased by 7 times. The strain could use sucrose, glucose, citrate, lactate and formate as electron donors for anaerobic respiration, and the reduction rates of AQDS ranked as sucrose (77%)glucose (66%)citrate (50%)lactate (33%)glycerol (25%)formate (17%). MFC-3 can also effectively reduce four types of Fe(III) oxides. After 25 d, the total Fe(II) concentration in the tests of using ferrihydrite, alpha-FeOOH, gamma-FeOOH or alpha-Fe2 O3 as electron acceptor reached 2.5, 2.1, 2.3 and 0.8 mmol x L(-1), respectively. As a strain of environmental origin, MFC-3 is quite useful for the study of extracellular respiration and bioremediation of chlorinated organic pollutants in Fe(III)/humic substance-rich environments.

The 5-d biochemical oxygen demand (BOD5) test is the most conventional method to determine the concentration of biodegradable organics in wastewater. However, this method is time-consuming and usually requires experience and skill to produce creditable results, which is also not suitable for on-line measurements. This study described a single-chamber mediator-less microbial fuel cell (MFC)-type BOD sensor as an alternative method to BOD5. In such MFC, MnO2 was used as the cathode catalyst instead of Pt and the expensive proton exchange membrane was replaced with the cation exchange membrane. The factors including the external resistance, pH of anolyte, the reaction time and rinse time on BOD sensor were explored, and the results were compared with the values determined by BOD5. The experimental results showed that the optimal conditions are: the external resistance of 12 k omega, pH of 7.0, and the reaction period of 2 h and the rinse time of 2-10 min. The low detection limit is 0.2 mg/L and the precision is 0.33%. This study indicates that MFC-type sensor can be used as a reliable method to determine BOD in wastewater, supported by the good linear correlation between BOD concentration and coulombs generation (regression coefficient, R2 = 0.9992) and the small relative error of 4% between MFC-type sensor and BOD5. Such device provides a low-cost, easy-operated, fast-response, sensitive and reliable method to measure BOD in wastewater, and also is suitable for on-line measurements.

This work studied the ability of Comamonas koreensis CY01 to reduce Fe(III) (hydr)oxides by coupling the oxidation of electron donors and the enhanced biodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) by the presence of Fe(III) (hydr)oxides. The experimental results suggested that strain CY01 can utilize ferrihydrite, goethite, lepidocrocite or hematite as the terminal electron acceptor and citrate, glycerol, glucose or sucrose as the electron donor. Strain CY01 could transform 2,4-D to 4-chlorophenol through reductive side-chain removal and dechlorination. Under the anaerobic conditions, Fe(III) reduction and 2,4-D biodegradation by strain CY01 occurred simultaneously. The presence of Fe(III) (hydr)oxides would significantly enhance 2,4-D biodegradation, probably due to the fact that the reactive mineral-bound Fe(II) species generated from Fe(III) reduction can abiotically reduce 2,4-D. This is the first report of a strain of C. koreensis capable of reducing Fe(III) (hydr)oxides and 2,4-D, which extends the diversity of iron-reducing bacteria associated with dechlorination.

The redox reactive and electron shuttling function of dissolved organic matter (DOM) derived from sewage sludge were studied with Shewanella cinica D14(T) as driving force of electron transfer. The results indicated that sludge DOM initially served as terminal electron acceptor obtaining electrons from the respiratory chain of quinone-reducing bacteria D14(T), then it translated to reduced DOM which can donate electrons to Fe(III) again. The electron donating capacities (EDC) of DOM increased from initial capacity of 2.2-14 micromol x g(-1) to 253-347 micromol x g(-1) after DOM was reduced by D14(T). The cyclic voltammetry measurements and multiple reduction-oxidation cycles experiments of DOM showed that two pairs of redox peaks were clearly observed and the EDC remained at a level of 150-250 micromol x g(-1) after three reduction-oxidation cycles, indicating that DOM can be recyclably used for electron transfer. In the system of hydrous ferric oxide (HFO) reduction by S. cinica D14(T), the reductive dissolution speed was improved with the presence of DOM, since that DOM was capable of acting as an electron shuttle between S. cinica D14(T) and HFO. These results demonstrate the important role of DOM in electron transfer process, and bring out a new perspective about the functions of DOM in the environment.

The rate of oxygen reduction reaction (ORR) at the cathode is a major factor affecting the performance of the microbial fuel cells (MFC). Results showed that when using Fe(III)-EDTA solution as catholyte, the ORR rate was significantly increased and the internal resistance was reduced, consequently leading to an increase in power output. With a concentration of Fe(III )-EDTA at 20.0 mmol/L in the catholyte, the MFC produced the voltage and power density at approximate 200.1 mV and 16.0 mW/m2, respectively, which was increased by 73.2% and 70.1% contrary to the MFC without the presence of Fe(III)-EDTA. The further experiment suggested that Fe(III)-EDTA functioned as electron shuttle to accelerate electron transfer. Fe(III)-EDTA received electron and got reduced to Fe(III)-EDTA, which further provided electrons to oxygen and got reoxidized at the same time. Therefore Fe(III)-EDTA can act as recyclable electron shuttles between cathode electrode and oxygen. The optimum condition in the case of using Fe(III)-EDTA as cathode electron shuttles was tested to be Fe(III)-EDTA concentration at 20.0 mmol/L and pH at 5.0, which allowed MFC produced the maximum power density of 100.9 mW/m2.

Corn steepwater containing 49,732.2 mg/L of chemical oxygen demand (COD) was used as fuel for a membrane electrode assembly microbial fuel cell (MEA-MFC), which could generate electricity and treat the wastewater at the same time. During a batch experiment of 94 days with a fixed 1,000 Omega external resistance, the maximum voltage output of 525.0 mV and power density of 169.6 mW/m2 were obtained after 17 days, corresponding to the current density, internal resistance and open voltage of 440.2 mA/m2, 350 Omega and 619.5 mV, respectively. However, data showed that the coulombic efficiency was only 1.6%, suggesting very limited COD was utilized for electricity generation. At the conclusion of the test, the removals of COD and ammonia-nitrogen were achieved 51.6% and 25.8%, respectively. This study demonstrates that corn steepwater can be used for power generation in MFC with simultaneous accomplishments of wastewater treatment, providing a novel approach for the safe disposal and recycle of corn steepwater.

An amorphous ferric hydroxysulfate named schwertmannite was synthesized by using bacterial oxidation of ferrous iron by resting A. ferrooxidans cells in acid ferrous sulfate solution (pH 2.5). The identification of the bacterially oxidized iron precipitate was carried out by SEM, XRD, FTIR and chemical analysis. Results showed that resting cells of A. ferrooxidans LX5 could completely oxidize ferrous ions to ferric ions in the FeSO4-H2O system after 2 days of incubation. The solution pH decreased from an initial 2.5 to 2.10, and about 15% of the ferrous iron was transformed into the red-brown precipitates. The subsequent characterization of the precipitates showed that the biotic, synthetic ferric hydroxysulfate was schwertmannite. Sorption edge measurement showed that the adsorption behavior of metal cations (e. g., Cu2+, Zn2+ and Cr3+) was pH-dependent. The adsorption increased with an increase in pH, and the maximum was found in a pH range of 6.0-7.0. For solution concentration of 50 mg x L(-1), the maximum adsorption efficiencies of Cu2+, Zn2+ and Cr3+ were 99.3%, 99.4% and 87.6%, respectively.