Co-reporter:Junlin Wen, Junhua Chen, Li Zhuang, Shungui Zhou
Biosensors and Bioelectronics 2017 Volume 90(Volume 90) pp:
Publication Date(Web):15 April 2017
DOI:10.1016/j.bios.2016.10.092
•Digoxigenin and biotin labeled probes were designed for antibody-like DNA nanostructure.•Strand displacement reaction transduced target signal into antibody-like nanostructures.•The DNA nanostructures were detected via enzyme-linked immunosorbent assay.•SDR-ELISA system offers ultrasensitive, high-throughput and isothermal DNA detection.An ultrasensitive and high-throughput nucleic acid detection system, termed as strand displacement reaction-enzyme linked immunosorbent assay (SDR-ELISA), has been developed on the basis of antibody-like DNA nanostructures. Three digoxigenin or biotin modified hairpin probes are utilized to construct antibody-like DNA nanostructures that feature affinity toward streptavidin and anti-digoxigenin antibody via isothermal target-triggered SDR amplification. These antibody-like nanostructures have been employed to conjugate horseradish-peroxidase-labeled anti-digoxigenin antibody with streptavidin that is immobilized on microliter plate wells for enzyme-linked colorimetric assay. The resulting SDR-ELISA system is ultrasensitive for target DNA with a low detection limit of 5 fM. Moreover, the SDR-ELISA system is capable of discriminating DNA sequences with single base mutations, and do so in a high-throughput manner by detection and quantification of up to 96 or 384 DNA samples in a single shot. This detection system is further applied to detect other DNA targets such as Shewanella oneidensis specific DNA sequence, which indicates the generality of proposed SDR-ELISA system. The integration of SDR amplification and convenient ELISA technique advances an intelligent strategy for ultrasensitive and high-throughput nucleic acid detection, which may be amenable for direct visual detection and quantification using an accompanying quantitative color chart.
Co-reporter:Shuping Qin, Zhijun Zhang, Linpeng Yu, Haijing Yuan, Timothy J. Clough, Nicole Wrage-Mönnig, Jiafa Luo, Shungui Zhou
Soil Biology and Biochemistry 2017 Volume 115(Volume 115) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.soilbio.2017.09.020
•Electric potential enhanced denitrification in a subsoil slurry.•Electric potential increased the abundance of Geobacter and Pseudomonas species.•N2 was the dominant end product of denitrification induced by electric potential.•Applying an electric potential could reduce subsoil nitrate concentrations.Laboratory culture studies have demonstrated that some microbial strains can use electrons generated by electrodes in the denitrification reaction. To test whether the native soil microbiota can use electrode electrons for denitrification, a subsoil slurry was incubated under an electric potential treatment. A potentiostat-poised (−500 mV) electrode served as an electron donor. The electric potential treatment enriches the electroactive denitrifying bacteria and accelerates the nitrate reduction in the subsoil slurry, with N2 as the dominant end product. These results demonstrate that an electrode can serve as an electron donor to enhance the subsoil denitrification. This finding supports the future development of a technique to remove accumulated nitrate in subsoils and reduce nitrate contamination in groundwater.
Co-reporter:Yong Yuan, Xixi Cai, Yueqiang Wang, Shungui Zhou
Chemical Geology 2017 Volume 456(Volume 456) pp:
Publication Date(Web):5 May 2017
DOI:10.1016/j.chemgeo.2017.02.020
Soluble and colloidal humic substances (HSs) involved in microbial extracellular electron transfer (EET) have been extensively investigated. However, little is known regarding EET at HS adlayers that are bound or complexed to the surface of natural solids. Here, we investigated EET process on seven types of HS adlayers by forming electroactive biofilms (EABs) and monitoring the biocurrent generation. The HS immobilized surfaces were carried out by firstly modifying glassy carbon surfaces via electrochemical reduction of aryl diazonium salts to create amino-functionalized surfaces, and then various HSs were covalently bonded to these amino groups via linkage molecules. The results showed that the HS adlayers formed from Leonardite, Elliott Soil and Pahokee Peat humic acids (HAs) facilitated EET by forming more active EABs, whereas the Suwannee River and Aldrich HAs, Suwannee River and Pahokee Peat fulvic acids (FAs) hindered EET. The EET positively correlated with electron accepting capacity and wettability of the HSs, and negatively correlated with the polarity of the HSs, and only weakly correlated with electron donating capacity and zeta potential of the HSs. Microscopic images showed that the thickness and viability of the biofilms varied based on the HS properties. A microbial community structure analysis showed that all of the biofilms were dominated by Proteobacteria and selectively enriched in Firmicutes and Bacteroidetes. Our study indicated that the HS adlayers significantly affected microbial EET, and these results provide a more comprehensive understanding of the HSs involved biogeochemical and biotransformation processes.Download high-res image (172KB)Download full-size image
Co-reporter:Junhua Chen, Junlin Wen, Li Zhuang and Shungui Zhou
Nanoscale 2016 vol. 8(Issue 18) pp:9791-9797
Publication Date(Web):14 Apr 2016
DOI:10.1039/C6NR01381C
An enzyme-free biosensor for the amplified detection of aflatoxin B1 has been constructed based on a catalytic DNA circuit. Three biotinylated hairpin DNA probes (H1, H2, and H3) were designed as the assembly components to construct the sensing system (triplex H1–H2–H3 product). Cascaded signal amplification capability was obtained through toehold-mediated strand displacement reactions to open the hairpins and recycle the trigger DNA. By the use of streptavidin-functionalized gold nanoparticles as the signal indicators, the colorimetric readout can be observed by the naked eye. In the presence of a target, the individual nanoparticles (red) aggregate into a cross-linked network of nanoparticles (blue) via biotin–streptavidin coupling. The colorimetric assay is ultrasensitive, enabling the visual detection of trace levels of aflatoxin B1 (AFB1) as low as 10 pM without instrumentation. The calculated limit of detection (LOD) is 2 pM in terms of 3 times standard deviation over the blank response. The sensor is robust and works even when challenged with complex sample matrices such as rice samples. Our sensing platform is simple and convenient in operation, requiring only the mixing of several solutions at room temperature to achieve visible and intuitive results, and holds great promise for the point-of-use monitoring of AFB1 in environmental and food samples.
Co-reporter:Yong Yuan, Tuan Guo, Xuhui Qiu, Jiahuan Tang, Yunyun Huang, Li Zhuang, Shungui Zhou, Zhaohui Li, Bai-Ou Guan, Xuming Zhang, and Jacques Albert
Analytical Chemistry 2016 Volume 88(Issue 15) pp:7609
Publication Date(Web):May 23, 2016
DOI:10.1021/acs.analchem.6b01314
Spectroelectrochemistry has been found to be an efficient technique for revealing extracellular electron transfer (EET) mechanism of electroactive biofilms (EABs). Herein, we propose a novel electrochemical surface plasmon resonance (EC-SPR) optical fiber sensor for monitoring EABs in situ. The sensor uses a tilted fiber Bragg grating (TFBG) imprinted in a commercial single-mode fiber and coated with nanoscale gold film for high-efficiency SPR excitation. The wavelength shift of the surface plasmon resonance (SPR) over the fiber surface clearly identifies the electrochemical activity of the surface localized (adjacent to the electrode interface) bacterial cells in EABs, which differs from the “bulk” detections of the conventional electrochemical measurements. A close relationship between the variations of redox state of the EABs and the changes of the SPR under potentiostatic conditions has been achieved, pointing to a new way to study the EET mechanism of the EABs. Benefiting from its compact size, high sensitivity, and ease of use, together with remote operation ability, the proposed sensor opens up a multitude of opportunities for monitoring EABs in various hard-to-reach environments.
Co-reporter:Junlin Wen, Junhua Chen, Li Zhuang, Shungui Zhou
Biosensors and Bioelectronics 2016 Volume 79() pp:656-660
Publication Date(Web):15 May 2016
DOI:10.1016/j.bios.2015.12.104
•A diblock hairpin probe was designed, constituting a hairpin block and a polyA block.•PolyA-tailed DNA junctions were fabricated by the introduction of target DNA•Enhanced sensitivity achieved by coupling catalytic hairpin assembly with AuNP assay.•The proposed sensor exhibited high sensitivity and specificity for detecting DNA.The detection of nucleic acid sequences is of great importance in a variety of fields. An ultrasensitive DNA sensing platform is constructed using elaborately designed diblock hairpin probes (DHPs) that are composed of hairpin and poly-adenine blocks. The introduction of an initiator DNA target triggers the catalytic assembly of probes DHP1, DHP2 and DHP3 to fabricate numerous poly-adenine-tailed branched DNA junctions, which significantly amplify the signal of the target-DNA-recognizing event without any enzyme. Coupled to a gold nanoparticle-based colorimetric assay, the amplified recognition signal can be quantitatively detected or visually read with the naked eye. The combination of the high-efficiency target-catalyzed DHP assembly and sensitive gold-based colorimetric assay offers an ultrasensitive detection of DNA with a detection limit of 0.1 pM and a dynamic range from 0.01 to 5 pM. The proposed sensing platform can discriminate even single-base mutations. Moreover, the sensing platform can be expanded to detect pollutant-degrading-bacteria-specific DNA sequences. The proposed sensing system should offer an alternative approach for the detection of nucleic acids in the fields of microbiology, biogeochemistry, and environmental sciences.
Co-reporter:Junhua Chen, Shungui Zhou
Biosensors and Bioelectronics 2016 Volume 77() pp:277-283
Publication Date(Web):15 March 2016
DOI:10.1016/j.bios.2015.09.042
•Three hairpin probes were utilized as the building blocks to fabricate a label-free DNA Y junction sensing platform.•Cascaded signal amplification was realized via a series of toehold-mediated strand displacement reactions.•Exonuclease III was employed as a protecting agent for the first time in biosensor design.•The resulting biosensor exhibited ultrasensitivity towards BPA at low concentration (5 fM).A label-free DNA Y junction sensing platform for the amplified detection of bisphenol A (BPA) has been constructed by the ingenious combination of toehold-mediated strand displacement and exonuclease III (Exo III)-based signal protection strategy. Three hairpin probes were utilized as the building blocks to fabricate the DNA Y junction with cascaded signal amplification via a series of toehold-mediated strand displacement reactions. Exo III was employed as a protecting agent for the first time to keep the Y-shaped molecular architecture intact, thereby greatly enhancing the fluorescence intensity of DNA intercalator SYBR Green I. The resulting biosensor exhibits ultrasensitivity towards BPA at low concentration (5 fM) without any labeling, modification, immobilization, or washing procedure. Our proposed sensing system also displays remarkable specificity to BPA against other possible interference molecules. Moreover, this DNA junction biosensor is robust and can be applied to the reliable monitoring of spiked BPA in environmental water samples with good recovery and accuracy. With the successful demonstration for BPA detection, the label-free DNA Y junction can be readily expanded to monitor other analytes in a simple, cost-effective, and ultrasensitive way by substituting the target-specific aptamer sequence.
Co-reporter:Yong Yuan, Ting Liu, Peng Fu, Jiahuan Tang and Shungui Zhou
Journal of Materials Chemistry A 2015 vol. 3(Issue 16) pp:8475-8482
Publication Date(Web):11 Mar 2015
DOI:10.1039/C5TA00458F
Conversion of sewage sludge (SS) into value-added biochar has garnered increasing attention due to its potential applications as a soil amendment and pollutant adsorbent. In this study, we propose a new application of the SS-derived biochar as an advanced bifunctional electrode material (anode and cathode) in microbial fuel cells (MFCs). To function as an anode, the SS amended with various amounts of coconut shell was pressed into a mold and then converted into SS-derived carbon monoliths (SMs) by heat treatment. Meanwhile, powdered SMs (PSMs) were used as the catalysts for oxygen reduction in the cathodes of the MFCs. The maximum power density of 969 ± 28 mW m−2 was achieved from the MFC with a SM anode and a PSM cathode, which was ca. 2.4 times that of the MFC with a graphite anode and a Pt cathode. The enhanced electrical conductivity of the SMs caused by amending the coconut shell resulted in the enrichment of exoelectrogens and the decrease in electron transfer resistance, which were responsible for the excellent performances of the as-prepared electrodes. This study suggests a promising method to convert SS into bifunctional electrode materials, offering a new opportunity for value-added applications of SS-derived biochar.
Co-reporter:Junhua Chen, Junlin Wen, Guiqin Yang and Shungui Zhou
Chemical Communications 2015 vol. 51(Issue 62) pp:12373-12376
Publication Date(Web):23 Jun 2015
DOI:10.1039/C5CC04347F
A label-free and enzyme-free three-way G-quadruplex junction sensing system for the amplified detection of 17β-estradiol has been constructed by the ingenious coupling of split G-quadruplex DNAzyme with toehold-mediated strand displacement. The biosensor is ultrasensitive, enabling the visual detection of 17β-estradiol concentrations as low as 1 fM without instrumentation.
Co-reporter:Ting Liu, Xixi Cai, Guochun Ding, Liqun Rao, Yong Yuan, Shungui Zhou
Journal of Power Sources 2015 Volume 294() pp:516-521
Publication Date(Web):30 October 2015
DOI:10.1016/j.jpowsour.2015.06.104
•The biocurrents decreased with increasing Ca2+ concentration in BESs.•Calcium ions affected the morphological structure and community structure of EABs.•The results reveal the important role of Ca2+ in the structure and activity of EABs.Calcium (Ca2+) plays an important role in guaranteeing the formation and structure of microbial biofilm. However, little is known regarding its influence on the structure and electron transfer properties of electroactive biofilms (EABs). In this study, advanced investigative techniques such as microscopy and electrochemistry are employed to characterize biofilm structure and electron transfer properties following growth at different Ca2+ concentrations in a bioelectrochemical system (BES). As revealed by electrochemical measurements, a lower current is obtained from the EABs formed in the presence of higher Ca2+ concentrations. The decline of the current is due to the dominance of non-active cells and non-exoelectrogens in the biofilms formed at high Ca2+ concentrations. The results of this study provide a better understanding of the effect of Ca2+ on EABs structure and thus electricity generation in BESs.
Co-reporter:Shungui Zhou, Junlin Wen, Junhua Chen, and Qin Lu
Environmental Science & Technology Letters 2015 Volume 2(Issue 2) pp:26-30
Publication Date(Web):January 20, 2015
DOI:10.1021/ez500405t
Microbial extracellular respiration (MER) involves the transfer of electrons to extracellular substrates and has significant environmental implications. Conventional methods for MER ability determination are reagent- and time-consuming, have a low throughput, or require noncommercial instruments. In this study, a plate-based colorimetric assay is proposed to measure MER ability. This method utilizes the peroxidase activity of the key components (multi-heme c-type cytochromes) of the extracellular electron-transfer network. The bacterial intrinsic peroxidase-catalyzed oxidation of chromogen (e.g., tetramethylbenzidine) resulted in a measurable color change correlated with the MER ability of the tested microorganisms. The results of the proposed colorimetric assay correspond well with those of traditional methods, such as the dissimilatory Fe(III) reduction method (Spearman’s ρ of 0.946; P < 0.01) and the electricity generation method (Spearman’s ρ of 0.893; P < 0.01). The proposed method allows researchers to identify extracellular respiring bacteria within several minutes and to measure their MER ability quantitatively by a plate-based assay.
Co-reporter:Dr. Junhua Chen;Dr. Shungui Zhou;Junlin Wen
Angewandte Chemie International Edition 2015 Volume 54( Issue 2) pp:446-450
Publication Date(Web):
DOI:10.1002/anie.201408334
Abstract
Concatenated logic circuits operating as a biocomputing keypad-lock security system with an automatic reset function have been successfully constructed on the basis of toehold-mediated strand displacement and three-way-DNA-junction architecture. In comparison with previously reported keypad locks, the distinctive advantage of the proposed security system is that it can be reset and cycled spontaneously a large number of times without an external stimulus, thus making practical applications possible. By the use of a split-G-quadruplex DNAzyme as the signal reporter, the output of the keypad lock can be recognized readily by the naked eye. The “lock” is opened only when the inputs are introduced in an exact order. This requirement provides defense against illegal invasion to protect information at the molecular scale.
Co-reporter:Qin Lu;Haoran Yuan;Jibing Li;Yong Zhao
Antonie van Leeuwenhoek 2015 Volume 107( Issue 3) pp:813-819
Publication Date(Web):2015 March
DOI:10.1007/s10482-014-0374-2
A Gram-stain positive, aerobic, motile, endospore-forming and rod-shaped bacterium, designated GSS05T, was isolated from a sludge compost sample and was characterized by means of a polyphasic taxonomic approach. Growth was observed to occur with 0–3 % (w/v) NaCl (optimum 1 %), at pH 5.5–10 (optimum pH 7.5) and at 15–50 °C (optimum 37 °C). According to the results of a phylogenetic analysis, strain GSS05T was found to belong to the genus Ornithinibacillus and to be related most closely to the type strains of Ornithinibacillus halotolerans and Ornithinibacillus contaminans (96.5 and 95.1 % 16S rRNA gene sequence similarity, respectively). The peptidoglycan amino acid type was determined to be A4β. The major respiratory quinone was identified as menaquinone-7 (MK-7). The polar lipid profile of strain GSS05T was found to contain a predominance of diphosphatidylglycerol, moderate amounts of phosphatidylglycerol and minor amounts of two unknown phospholipids and two unknown lipids. The G+C content of genomic DNA was determined to be 42.1 mol%. The dominant cellular fatty acids were identified as iso-C15:0 and anteiso-C15:0. The phenotypic, chemotaxonomic, phylogenetic and genotypic data indicated that strain GSS05T represents a novel species of the genus Ornithinibacillus, for which the name Ornithinibacillus composti sp. nov. is proposed. The type strain is GSS05T (=CCTCC AB 2013261T = KCTC 33192T).
Co-reporter:Xiaowen Cui;Yueqiang Wang;Jing Liu;Ming Chang;Yong Zhao
Archives of Microbiology 2015 Volume 197( Issue 4) pp:513-520
Publication Date(Web):2015 May
DOI:10.1007/s00203-015-1082-7
A Cr(VI)-tolerant, Gram-staining-positive, rod-shaped, endospore-forming and facultative anaerobic bacterium, designated as GSS04T, was isolated from a heavy-metal-contaminated soil. Strain GSS04T was Cr(VI)-tolerant with a minimum inhibitory concentration of 600 mg l−1 and was capable of reducing Cr(VI) under both aerobic and anaerobic conditions. Growth occurred with presence of 0–3 % (w/v) NaCl (optimum 1 %), at pH 5.5–10.0 (optimum pH 7.0) and 15–50 °C (optimum 30–37 °C). The main respiratory quinone was MK-7 and the major fatty acids were anteiso-C15:0 and iso-C15:0. The DNA G+C content was 41.1 mol%. The predominant polar lipid was diphosphatidylglycerol. Based on 16S rRNA gene sequence similarity, the closest phylogenetic relative was Bacillus shackletonii DSM 18868T (97.6 %). The DNA–DNA hybridization between GSS04T and its closest relatives revealed low relatedness (<70 %). The results of phenotypic, chemotaxonomic and genotypic analyses clearly indicated that strain GSS04T represents a novel species of the genus Bacillus, for which the name Bacillus dabaoshanensis sp. nov. is proposed. The type strain is GSS04T (=CCTCC AB 2013260T = KCTC 33191T).
Co-reporter:Zhen Yu;Chu Wu;Gui-Qin Yang;Shun-Gui Zhou
Current Microbiology 2015 Volume 70( Issue 1) pp:135-140
Publication Date(Web):2015 January
DOI:10.1007/s00284-014-0693-6
A Gram positive, thermophilic, and filamentous bacterium, designated strain GIESS004T, 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 GIESS004T contained MK-7 as the predominant menaquinone and iso-C16:0, iso-C15:0 and iso-C17:0 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 GIESS004T was associated with the genus Planifilum and formed a cluster with its closest relative of Planifilum composti P8T (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 P8T. On the basis of the polyphasic taxonomic results, strain GIESS004T (= CCTCC AB2013107T = MCCC 1K00414T) is designated as the type strain of a novel species of the genus Planifilum, for which the name Planifilum caeni sp. nov. is proposed.
Co-reporter:Dr. Junhua Chen;Dr. Shungui Zhou;Junlin Wen
Angewandte Chemie 2015 Volume 127( Issue 2) pp:456-460
Publication Date(Web):
DOI:10.1002/ange.201408334
Abstract
Concatenated logic circuits operating as a biocomputing keypad-lock security system with an automatic reset function have been successfully constructed on the basis of toehold-mediated strand displacement and three-way-DNA-junction architecture. In comparison with previously reported keypad locks, the distinctive advantage of the proposed security system is that it can be reset and cycled spontaneously a large number of times without an external stimulus, thus making practical applications possible. By the use of a split-G-quadruplex DNAzyme as the signal reporter, the output of the keypad lock can be recognized readily by the naked eye. The “lock” is opened only when the inputs are introduced in an exact order. This requirement provides defense against illegal invasion to protect information at the molecular scale.
Co-reporter:Jiahuan Tang, Shanshan Chen, Yong Yuan, Xixi Cai, Shungui Zhou
Biosensors and Bioelectronics 2015 Volume 71() pp:387-395
Publication Date(Web):15 September 2015
DOI:10.1016/j.bios.2015.04.074
•A graphene modified anode is fabricated for targeting high-performance in MFCs.•The graphene layer on graphite is formed in situ with a facile electrolysis approach.•The graphene-based anode achieves 1.72-fold higher power density over graphite plate.•The macroporous graphene layer is also promising for transient charge storage.Graphene can be used to improve the performance of the anode in a microbial fuel cell (MFC) due to its good biocompatibility, high electrical conductivity and large surface area. However, the chemical production and modification of the graphene on the anode are environmentally hazardous because of the use of various harmful chemicals. This study reports a novel method based on the electrochemical exfoliation of a graphite plate (GP) for the in situ formation of graphene layers on the surface of a graphite electrode. When the resultant graphene-layer-based graphite plate electrode (GL/GP) was used as an anode in an MFC, a maximum power density of 0.67±0.034 W/m2 was achieved. This value corresponds to 1.72-, 1.56- and 1.26-times the maximum power densities of the original GP, exfoliated-graphene-modified GP (EG/GP) and chemically-reduced-graphene-modified GP (rGO/GP) anodes, respectively. Electrochemical measurements revealed that the high performance of the GL/GP anode was attributable to its macroporous structure, improved electron transfer and high electrochemical capacitance. The results demonstrated that the proposed method is a facile and environmentally friendly synthesis technique for the fabrication of high-performance graphene-based electrodes for use in microbial energy harvesting.
Co-reporter:Guiqin Yang;Shanshan Chen;Yongfeng Liu
Standards in Genomic Sciences 2015 Volume 10( Issue 1) pp:
Publication Date(Web):2015 December
DOI:10.1186/s40793-015-0117-7
Strain GSS01T (=KCTC 4545=MCCC 1 K00269) is the type strain of the species Geobacter soli. G. soli strain GSS01T is of interest due to its ability to reduce insoluble Fe(III) oxides with a wide range of electron donors. Here we describe some key features of this strain, together with the whole genome sequence and annotation. The genome of size 3,657,100 bp contains 3229 protein-coding and 54 RNA genes, including 2 16S rRNA genes. The genome of strain GSS01Tcontains 76 predicted cytochrome genes, 24 pilus assembly protein genes and several other genes, which were proposed to be related to the reduction of insoluble Fe(III) oxides. The genes associated with the electron donors and acceptors of strain GSS01T were predicted in the genome. Information gained from its sequence will be relevant to the future elucidation of extracellular electron transfer mechanism during the reduction of Fe(III) oxides.
Co-reporter:Junhua Chen, Shungui Zhou, and Junlin Wen
Analytical Chemistry 2014 Volume 86(Issue 6) pp:3108
Publication Date(Web):February 24, 2014
DOI:10.1021/ac404170j
A disposable strip biosensor for the visual detection of Hg2+ in aqueous solution has been constructed on the basis of Hg2+-triggered toehold binding and exonuclease III (Exo III)-assisted signal amplification. Thymine-thymine (T-T) mismatches in the toehold domains can serve as specific recognition elements for Hg2+ binding with the help of T-Hg2+-T base pairs to initiate toehold-mediated strand displacement reaction. Exo III-catalyzed target recycling strategy is introduced to improve the sensitivity. Using gold nanoparticles as a tracer, the output signals can be directly observed by the naked eye. The assay is ultrasensitive, enabling the visual detection of trace amounts of Hg2+ as low as 1 pM without instrumentation. This sensing system also displays remarkable specificity to Hg2+ against other possible competing ions. This sensor is robust and can be applied to the reliable monitoring of spiked Hg2+ in environmental water samples with good recovery and accuracy. With the advantages of cost-effectiveness, simplicity, portability, and convenience, the disposable strip biosensor will be a promising candidate for point-of-use monitoring of Hg2+ in environmental and biological samples.
Co-reporter:Min Wu;Junlin Wen;Ming Chang;Guiqin Yang
Antonie van Leeuwenhoek 2014 Volume 105( Issue 4) pp:781-790
Publication Date(Web):2014 April
DOI:10.1007/s10482-014-0134-3
A Gram-stain negative, motile, rod-shaped bacterium, designated strain WM-2T, was isolated from a forest soil in Sihui City, South China, and characterized by means of a polyphasic approach. Growth occurred with 0–5 % (w/v) NaCl (optimum 0–1 %) and at pH 5.0–10.5 (optimum pH 8.5) and 4–40 °C (optimum 30 °C) in Luria–Bertani medium. Comparative 16S rRNA gene sequence analyses showed that strain WM-2T is a member of the genus Pseudomonas and most closely related to P.guguanensis, P. oleovorans subsp. lubricantis, P. toyotomiensis, P. alcaliphila and P. mendocina with 97.1–96.6 % sequence similarities. In terms of gyrB and rpoB gene sequences, strain WM-2T showed the highest similarity with the type strains of the species P. toyotomiensis and P. alcaliphila. The DNA–DNA relatedness values of strain WM-2T with P.guguanensis and P. oleovorans subsp. lubricantis was 48.7 and 37.2 %, respectively. Chemotaxonomic characteristics (the main ubiquinone Q-9, major fatty acids C18:1ω7c/C18:1ω6c, C16:0 and C16:1ω7c/C16:1ω6c and DNA G+C content 65.2 ± 0.7 mol%) were similar to those of members of the genus Pseudomonas. Polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unknown aminophospholipid, an unknown phospholipid and five unknown lipids. According to the results of polyphasic analyses, strain WM-2T represents a novel species in the genus Pseudomonas, for which the name Pseudomonas sihuiensis sp. nov. is proposed. The type strain is WM-2T (=KCTC 32246T=CGMCC 1.12407T).
Co-reporter:Junlin Wen, Shungui Zhou, Yong Yuan
Biosensors and Bioelectronics 2014 Volume 52() pp:44-49
Publication Date(Web):15 February 2014
DOI:10.1016/j.bios.2013.08.022
•A sensitive immunosensor developed upon Ab/AuNPs/BSA/GO conjugate.•BSA-modified graphene oxide carries lots of gold nanoparticles and antibody.•Signal amplification achieved through efficient GO-carrier and gold-silver staining.•The method exhibited detection limit of 12 cfu/mL and feasibility in real sample.The genus Shewanella is ubiquitous in environment and has been extensively studied for their applications in bioremediation. A novel immunoassay for ultrasensitive detection of Shewanella oneidensis was presented based on graphene oxide (GO) as nanogold carrier with silver enhancement strategy. The enhanced sensitivity was achieved by employing conjugate-featuring gold nanoparticles (AuNPs) and antibodies (Ab) assembled on bovine serum albumin (BSA)-modified GO (Ab/AuNPs/BSA/GO). After a sandwich-type antigen–antibody reaction, Ab/AuNPs/BSA/GO conjugate binding on the target analyte produced an enhanced immune-recognition response by the reduction of silver ion in the present of hydroquinone. The deposited silver metal was dissolved with nitric acid and subsequently quantified by anodic stripping voltammetry. The high AuNPs loading capacity of GO and the obvious signal amplification by gold-catalyzed silver deposition offer an excellent detection method with a wide range of linear relationship between 7.0×101 and 7.0×107 cfu/mL. Furthermore, the immunoassay developed in this work exhibited high sensitivity, acceptable stability and reproducibility. This simple and sensitive assay method has promising application in various fields for rapid detection of bacteria, protein and DNA.
Co-reporter:Jibing Li;Guiqin Yang;Min Wu;Yong Zhao
Antonie van Leeuwenhoek 2014 Volume 106( Issue 2) pp:357-363
Publication Date(Web):2014 August
DOI:10.1007/s10482-014-0208-2
A Gram-stain positive, facultative aerobic bacterium, designated as strain GSS03T, was isolated from a paddy field soil. The cells were observed to be endospore forming, rod-shaped and motile with flagella. The organism was found to grow optimally at 35 °C at pH 7.0 and in the presence of 1 % NaCl. The strain was classified as a novel taxon within the genus Bacillus on the basis of phenotypic and phylogenetic analyses. The closest phylogenetic relatives were identified as Bacilluspsychrosaccharolyticus DSM 6T (97.61 %), Bacillus muralis DSM 16288T (97.55 %), Bacillusasahii JCM 12112T (97.48 %), Bacillussimplex DSM 1321T (97.48 %) and “Bacillus frigoritolerans” DSM 8801T (97.38 %). The menaquinone was identified as MK-7, the major cellular fatty acid was identified as anteiso-C15:0 and the major cellular polar lipids as phosphatidylethanolamine, phosphatidylmonomethylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and three unknown polar lipids. The DNA G+C content was determined to be 40.2 mol%. The DNA–DNA relatedness with the closest relatives was below 48 %. Therefore, on the basis of all the results, strain GSS03T is considered to represent a novel species within the genus Bacillus, for which the name Bacillus huizhouensis sp. nov. is proposed. The type strain is GSS03T (=KCTC 33172T =CCTCC AB 2013237T).
Co-reporter:Chu Wu;Ming Chang;Guiqin Yang;Li Zhuang
Antonie van Leeuwenhoek 2014 Volume 106( Issue 2) pp:235-241
Publication Date(Web):2014 August
DOI:10.1007/s10482-014-0186-4
A novel Gram-stain-positive, motile, hemolytic, endospore-forming and rod-shaped bacterium was isolated and designated as strain GIESS003T. The strain grew optimally at 35 °C, at pH 7.0–7.5, and with 3.0–3.5 % (w/v) NaCl. The 16S rRNA gene sequence analysis indicated that strain GIESS003T was associated with the genus Ornithinibacillus and was most closely related to the type strain of Ornithinibacilluscontaminans (96.5 % similarity). The major cellular fatty acids were iso-C15:0 and anteiso-C15:0. The polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The major respiratory quinone was menaquinone-7. Strain GIESS003T contained a peptidoglycan of type A4βl-Orn-d-Asp. The G+C content of genomic DNA was 40.1 mol%. On the basis of polyphasic evidence from this study, a new species of the genus Ornithinibacillus, Ornithinibacillusheyuanensis sp. nov., is proposed, with strain GIESS003T (=KCTC 33159T=CCTCC 2013106T) as the type strain.
Co-reporter:Jibing Li;Guiqin Yang;Qin Lu;Yong Zhao
Antonie van Leeuwenhoek 2014 Volume 106( Issue 4) pp:789-794
Publication Date(Web):2014 October
DOI:10.1007/s10482-014-0248-7
A Gram-stain positive, rod-shaped, endospore-forming and facultatively anaerobic halotolerant bacterium, designated as C-89T, was isolated from a paddy field soil in Haikou, Hainan Province, People’s Republic of China. Optimal growth was observed at 37 °C and pH 7.0 in the presence of 4 % NaCl (w/v). The predominant menaquinone was identified as MK-7, the major cellular fatty acids were identified as anteiso-C15:0 and iso-C15:0, and the major cellular polar lipids were identified as phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and two unknown phospholipids. The peptidoglycan type was determined to be based on meso-DAP. Based on 16S rRNA gene sequence similarity, the closest phylogenetic relatives were identified as Bacillus vietnamensis JCM 11124T (98.8 % sequence similarity), Bacillus aquimaris JCM 11545T (98.6 %) and Bacillusmarisflavi JCM 11544T (98.5 %). The DNA G+C content of strain C-89T was determined to be 45.4 mol%. The DNA–DNA relatedness values of strain C-89T with its closest relatives were below 18 %. Therefore, on the basis of phylogenetic, chemotaxonomic, and phenotypic results, strain C-89T can be considered to represent a novel species within the genus Bacillus, for which the name Bacillus haikouensis sp. nov., is proposed. The type strain is C-89T (=KCTC 33545T = CCTCC AB 2014076T).
Co-reporter:Jia Tang;Guiqin Yang;Junlin Wen;Zhen Yu
Archives of Microbiology 2014 Volume 196( Issue 9) pp:629-634
Publication Date(Web):2014 September
DOI:10.1007/s00203-014-1001-3
A novel thermophilic, Gram-staining positive bacterium, designated DX-2T, was isolated from the anode biofilm of a microbial fuel cell. Cells of the strain were oxidase positive, catalase positive, facultative anaerobic, motile rods. The isolate grew at 30–60 °C (optimum 50 °C) and pH 5–9 (optimum pH 8–8.5). The pairwise 16S rRNA gene sequence similarities showed that strain DX-2T was most closely related to Bacillus fumarioli LMG 17489T (96.2 %), B. firmus JCM 2512T (96.0 %) and B.foraminis DSM 19613T (95.7 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DX-2T formed a cluster with B. smithii (95.5 %) and B. infernus (94.9 %). The genomic G+C content of DX-2T was 43.7 mol%. The predominant respiratory quinone was MK-7. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and unknown phospholipids. The major cellular fatty acid was iso-C16:0. Based on its phenotypic characteristics, chemotaxonomic features, and results of phylogenetic analysis, the strain was identified to represent a distinct novel species in the genus Bacillus, and the name proposed is B. thermophilum sp. nov. The type strain is DX-2T (=CCTCC AB2012194T = KCTC 33128T).
Co-reporter:Jia Tang;Guiqin Yang;Yueqiang Wang;Chu Wu
Current Microbiology 2014 Volume 68( Issue 5) pp:629-634
Publication Date(Web):2014 May
DOI:10.1007/s00284-014-0518-7
A halophilic, aerobic bacterium, designated GD01T, was isolated from a mangrove forest soil near the South China Sea. Cells of strain GD01T 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 GD01T formed a cluster with O. profundus DSM 18246T (96.4 % 16S rRNA gene sequence similarity), O. caeni KCTC 13061T (95.4 %), and O. oncorhynchi JCM 12661T (94.5 %). The G+C content of strain GD01T 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 GD01T (=CCTCC AB 2012863T = KCTC 33101T).
Co-reporter:Yong Yuan, Shungui Zhou, and Jiahuan Tang
Environmental Science & Technology 2013 Volume 47(Issue 9) pp:4911-4917
Publication Date(Web):March 28, 2013
DOI:10.1021/es400045s
Mass transport within a cathode, including OH– transport and oxygen diffusion, is important for the performance of air-cathode microbial fuel cells (MFCs). However, little is known regarding how mass transport profiles are associated with MFC performance and how they are affected by biofilm that inevitably forms on the cathode surface. In this study, the OH– and oxygen profiles of a cathode biofilm were probed in situ in an MFC using microelectrodes. The pH of the catalyst layer interface increased from 7.0 ± 0.1 to 9.4 ± 0.3 in a buffered MFC with a bare cathode, which demonstrates significant accumulation of OH– in the cathode region. Furthermore, the pH of the interface increased to 10.0 ± 0.3 in the presence of the local biofilm, which indicates that OH– transport was severely blocked. As a result of the significant OH– accumulation, the maximum power density of the MFC decreased from 1.8 ± 0.1 W/m2 to 1.5 ± 0.08 W/m2. In contrast, oxygen crossover, which was significant under low current flow conditions, was limited by the cathode biofilm. As a result of the blocked oxygen crossover, higher MFC coulombic efficiency (CE) was achieved in the presence of the cathode biofilm. These results indicate that enhanced OH– transport and decreased oxygen crossover would be beneficial for high-performance MFC development.
Co-reporter:Yong Yuan, Shungui Zhou, Yi Liu, and Jiahuan Tang
Environmental Science & Technology 2013 Volume 47(Issue 24) pp:14525-14532
Publication Date(Web):November 15, 2013
DOI:10.1021/es404163g
Microbial fuel cells (MFCs) are a promising technology to recover electrical energy from different types of waste. However, the power density of MFCs for practical applications is limited by the anode performance, mainly resulting from low bacterial loading capacity and low extracellular electron transfer (EET) efficiency. In this study, an open three-dimensional (3D) structured electrode was fabricated using a natural loofah sponge as the precursor material. The loofah sponge was directly converted into a continuous 3D macroporous carbon material via a simple carbonization procedure. The loofah sponge carbon (LSC) was decorated with nitrogen-enriched carbon nanoparticles by cocarbonizing polyaniline-hybridized loofah sponges to improve their microscopic structures. The macroscale porous structure of the LSCs greatly increased the bacterial loading capacity. The microscale coating of carbon nanoparticles favored EET due to the enhanced interaction between the bacteria and the anode. By using a single-chamber MFC equipped with the fabricated anode, a power density of 1090 ± 72 mW m–2 was achieved, which is much greater than that obtained by similarly sized traditional 3D anodes. This study introduces a promising method for the fabrication of high-performance anodes from low-cost, sustainable natural materials.
Co-reporter:Yong Yuan, Shungui Zhou, Guiqin Yang and Zhen Yu
RSC Advances 2013 vol. 3(Issue 41) pp:18844-18848
Publication Date(Web):07 Aug 2013
DOI:10.1039/C3RA42850H
Interest in biomaterial-combined memory devices is on the rise due to their redox properties and electron transport capacities in nature. However, many attempts have been made to develop the protein-based memory devices. Here, we developed a novel biomemory device that was comprised of living Shewanella oneidensis MR-1 cells and microbially reduced graphene. Charge storage and release properties of the composite biofilm were investigated with electrochemical methods. The results showed the redox behavior of in vivo c-type cytochromes with electrochemically controllable electric states regarded as “write” and “erase” processes. Furthermore, the graphene modified biofilm had significantly improved charge storage and release properties due to the synergetic effects between graphene and the electrochemically active biofilm. The current signal of the biomemory device was two orders higher than those of protein-based biomemory systems. The findings provide a new opportunity for memory design since the composite biofilm can be inexpensively produced and is self-repairable and replicable, which is advantageous to abiological and protein-based biomemory devices.
Co-reporter:Ran Bi;Qin Lu;Weimin Yu;Yong Yuan
Journal of Soils and Sediments 2013 Volume 13( Issue 9) pp:1553-1560
Publication Date(Web):2013 October
DOI:10.1007/s11368-013-0748-5
Soil dissolved organic matter (DOM) as the labile fraction of soil organic carbon (SOC) is able to facilitate biogeochemical redox reactions effecting soil respiration and carbon sequestration. In this study, we took soil samples from 20 sites differing in land use (forest and agriculture) to investigate the electron transfer capacity of soil DOM and its potential relationship with soil respiration.DOM was extracted from 20 soil samples representing different land uses: forest (nos. 1–12) and agriculture (nos. 13–20) in Guangdong Province, China. Chronoamperometry was employed to quantify the electron transfer capacity (ETC) of the DOM, including electron acceptor capacity (EAC) and electron donor capacity (EDC), by applying fixed positive or negative potentials to a working electrode in a conventional three-electrode cell. The reversibility of electron accepting from or donating to DOM was measured by applying switchable potentials to the working electrode in the electrochemical system with the multiple-step potential technique. Carbon dioxide produced by soil respiration was measured with a gas chromatograph.Forest soil DOM samples showed higher ETC and electron reversible rate (ERR) than agricultural soil DOM samples, which may be indicative of higher humification rate and microbial activity in forest soils. The average soil respiration of forest soil (nos. 1–12) and agricultural soil (nos. 13–10) was 26.34 and 18.58 mg C g−1 SOC, respectively. Both EDC and EAC of soil DOM had close relationship with soil respiration (p < 0.01). The results implied that soil respiration might be accelerated by the electroactive moieties contained in soil DOM, which serve as electron shuttles and facilitate electron transfer reactions in soil respiration and SOC mineralization.DOM of forest soils showed higher ETC and ERR than DOM of agricultural soils. As soil represents one of the largest reservoirs of organic carbon, soil respiration affects C cycle and subsequently CO2 concentration in the atmosphere. As one of the important characteristics of soil DOM related to soil respiration, ETC has a significant impact on greenhouse gas emission and soil carbon sequestration but has not been paid attention to.
Co-reporter:Yong Yuan;Tian Yuan;Li Zhuang;Fangbai Li
Journal of Soils and Sediments 2013 Volume 13( Issue 1) pp:56-63
Publication Date(Web):2013 January
DOI:10.1007/s11368-012-0585-y
Dissolved organic matter (DOM) has been shown to be an efficient electron transfer facilitator in biogeochemical reactions due to its ability to mediate redox reactions. It has been known that various fractions of DOM differed in their chemical and biogeochemical behaviors in environment. However, there has been relatively little work directed at predicting the dependence of redox properties of DOM on its fractions.DOM was extracted from sewage sludge compost. Freeze-dried DOM was grouped into three fractions of different molecular sizes (<3,500, 3,500–14,000, and >14,000 Da) using dialysis bags (Spectra/Por 3 and 4, Spectrum Industries, California, US). Cycle voltammetry was used to investigate the redox behavior of the fractions. Chronoamperometry was employed to study their electron accepting capacities and electron donating capacities by applying fixed positive or negative potential to the working electrode in a conventional three-electrode cell. Fourier-transform infrared and three-dimensional excitation/emission matrix fluorescence spectroscopies were used to determine the functional groups in the fractions. Shewanella putrefaciens 200 (SP200) and Klebsiella pneumoniae L17 (L17) were used for all microbial iron(III) reduction experiments.Electrochemical methods show that the electron transfer capacity (ETC) of DOM depends on its molecular weight, and ETC is in the order of high-molecular weight DOM (H-DOM) > moderate-molecular weight DOM > low-molecular weight DOM. The same trend is discovered in the DOM-stimulated iron(III) oxide bioreduction where DOM fractions act as electron shuttles transferring electrons from the Fe(III)-reducing bacteria to the iron oxide. Both spectroscopic and cyclic voltammogram assays show the highest abundance of redox moieties associated to H-DOM, which is possibly responsible for its strongest electron-shuttling ability.DOM has a wide molecular weight (MW) distribution due to the complexity of its chemical composition and structure. In addition to structural variations, DOM fractions with different MW have different redox properties and electron-shuttling capacities in microbial Fe(III) reduction. The results are of great significance for further studies on DOM geochemical behavior in environment.
Co-reporter:Zhen Yu;Ming Chang;Min Wu;Guiqin Yang
Archives of Microbiology 2013 Volume 195( Issue 12) pp:815-822
Publication Date(Web):2013 December
DOI:10.1007/s00203-013-0930-6
A Gram-staining-negative, rod-shaped and motile with several polar flagellums bacterium, designated WM-3T, was isolated from a rice paddy soil in South China. Growth occurred with 0–3.0 % (w/v) NaCl (optimum 2.0 %), at pH 5.5–9.0 (optimum pH 7.0) and at 25–42 °C (optimum 30–37 °C) in liquid Reasoner’s 2A medium. Analysis of the 16S rRNA gene and gyrB gene sequences revealed that strain WM-3T was most closely related to the type strains of the species Pseudomonas linyingensis and Pseudomonas sagittaria. Its sequence similarities with P. linyingensis CGMCC 1.10701T and P. sagittaria JCM 18195T were 97.4 and 97.3 %, respectively, for 16S rRNA gene, and were 94.1 and 94.2 %, respectively, for gyrB gene. DNA–DNA hybridization between strain WM-3T and these two type strains showed relatedness of 35.6 and 30.9 %, respectively. G+C content of genomic DNA was 69.4 mol%. The whole-cell fatty acids mainly consisted of C16:0 (30.0 %), C16:1ω6c and/or C16:1ω7c (19.3 %) and C18:1ω6c and/or C18:1ω7c (16.3 %). The results of phenotypic, chemotaxonomic and genotypic analyses clearly indicated that strain WM-3T belongs to genus Pseudomonas but represents a novel species, for which the name Pseudomonasoryzae sp. nov. is proposed. The type strain is WM-3T (=KCTC 32247T =CGMCC 1.12417T).
Co-reporter:Yue-Qiang Wang;Yong Yuan;Zhen Yu;Gui-Qin Yang;Shun-Gui Zhou
Current Microbiology 2013 Volume 67( Issue 6) pp:718-724
Publication Date(Web):2013 December
DOI:10.1007/s00284-013-0426-2
A Gram-positive, facultative anaerobic, motile, endospore-forming rod strain, designated DX-4T, 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 with <6 % (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-4T is a member of the genus Bacillus. The results of phenotypic, chemotaxonomic, and genotypic analyses clearly indicated that strain DX-4T represents a novel species, for which the name Bacillusborbori sp. nov. is proposed. The type strain is DX-4T (= CCTCC AB2012196T = KCTC 33103T).
Co-reporter:Guiqin Yang;Ming Chen;Zhi Liu;Yong Yuan
Antonie van Leeuwenhoek 2013 Volume 104( Issue 5) pp:715-724
Publication Date(Web):2013 November
DOI:10.1007/s10482-013-9979-0
An Fe(III) oxide-reducing bacterium designated as SgZ-3T, which could couple glucose oxidation to Fe(III) oxide reduction for energy conservation, was isolated from an electrochemical biofilm. The isolate was Gram-negative, catalase-positive and oxidase-negative, and facultative anaerobic. NaCl was not required for growth, but NaCl concentrations up to 5 % (w/v) were tolerated. Growth occurred in TSB (tryptic soy broth) at 20–40 °C (optimum 30 °C) and at pH 6.0–7.5 (optimum 7.0). Phototrophic growth could not be demonstrated. No vesicular photosynthetic membrane was observed. Bacteriochlorophyll α and carotenoids were absent. Biotin and thiamine were required as growth factors for the isolate. Phylogenetic analysis of the 16S rRNA gene sequence placed strain SgZ-3T within the family Rhodobacteraceae and affiliated with an phototrophic genera Rhodobacter. The G+C content of the genomic DNA was 68.6 mol%. Strain SgZ-3T contained Q-10 as the predominant quinone. The major cellular fatty acids were C18:1ω6c and/or C18:1ω7c (66.9 %) and C16:0 (9.5 %). Based on its phenotypic and phylogenetic properties, chemotaxonomic analysis and the results of physiological and biochemical tests, strain SgZ-3T (=KACC 16603T = CCTCC AB2012026T) was designated as the type strain of a new genus and a novel species of the family Rhodobacteraceae, for which the name Sinorhodobacterferrireducens sp. nov. was proposed.
Co-reporter:Li Zhuang, Yong Yuan, Guiqin Yang, Shungui Zhou
Electrochemistry Communications 2012 Volume 21() pp:69-72
Publication Date(Web):July 2012
DOI:10.1016/j.elecom.2012.05.010
Here we reported a novel one-pot method for biocathode fabrication in microbial fuel cell (MFC), by which the microbially-reduced graphene was implanted into cathodic biofilm, leading to the in situ construction of graphene/biofilm composites with a three-dimensional structure. The maximum power density of the MFC with graphene-biocathode increased by 103% compared with the MFC with carbon cloth-biocathode. Electrochemical analyses showed that the graphene-biocathode had faster electron transfer kinetics and less internal resistance than the carbon cloth-biocathode. As an effective biocathode material, graphene/biofilm composites could enhance the electrocatalytic activity towards oxygen reduction, and facilitate the electron transfer between bacteria and electrode.Highlights► Reported a novel one-pot method for biocathode fabrication in microbial fuel cell. ► Graphene/biofilm composites with a 3-D structure were in situ formed on cathode. ► The maximum power density of the MFC increased by 103% after fabrication. ► Graphene/biofilm has higher electrocatalytic activity towards oxygen reduction. ► This work developed a facile method to assemble a new biocathode MFC.
Co-reporter:Yong Yuan;Qing Chen;Li Zhuang;Pei Hu
Journal of Chemical Technology and Biotechnology 2012 Volume 87( Issue 1) pp:80-86
Publication Date(Web):
DOI:10.1002/jctb.2686
Abstract
BACKGROUND: Electricity can be generated directly from sewage sludge with a microbial fuel cell (MFC), combining degradation of organic matter. This study constructed a novel insert-type air-cathode microbial fuel cell (ITAC-MFC) as an alternative to a sediment-type MFC and a two-chambered MFC for the generation of bioelectricity and the degradation of sewage sludge organic matter. Meanwhile, a pH adjustment was carried out to enhance substrate bioavailability of sludge and to suppress methane production in the MFC.
RESULTS: A maximum power density of 73 ± 5 mW m−2 was obtained at sludge pH 10.0, much higher than those of 33 ± 3 and 4 ± 0.5 mW m−2 obtained at pH 8.0 and 6.0, respectively. It was observed that the soluble chemical oxygen demand (SCOD) of sewage sludge at pH 10.0 was almost three times greater than that at pH 6.0. At the same time, the total chemical oxygen demand (TCOD) removal and coulombic efficiency (CE) at pH 10.0 were also much higher than at the other two conditions.
CONCLUSIONS: The results demonstrated that improved electricity production and organic degradation could be achieved by maintaining the sludge pH at 10.0 in an MFC. ITAC-MFC offers an attractive alternative for the environmentally-friendly removal of organic matter in sewage sludge. Copyright © 2011 Society of Chemical Industry
Co-reporter:Yong Yuan, Shungui Zhou, Nan Xu, Li Zhuang
Colloids and Surfaces B: Biointerfaces 2011 Volume 82(Issue 2) pp:641-646
Publication Date(Web):1 February 2011
DOI:10.1016/j.colsurfb.2010.10.015
This study used a simple and efficient electrochemical technique, cyclic voltammogram (CV), to quantitatively measure the electron transfer capability of anodic biofilms enriched with acetate and glucose in single-chamber microbial fuel cells (MFCs). Two pairs of distinct redox peaks were observed by CV measurements in both biofilms, identical to the CV features of a pure Geobacter strain. The CVs also revealed a higher density of electroactive species in the acetate-enriched biofilm than that in the glucose-enriched biofilm. Based on the scan rate analysis, the apparent electron transfer rate constants (kapp) in the acetate-enriched biofilm and glucose-enriched biofilm were determined to be 0.82 and 0.15 s−1, respectively, which supported the higher power output of the MFC fed with acetate. Meanwhile, the pH dependence of the biofilms was studied by monitoring the changes of the biofilm redox peak currents and potentials. It is concluded that redox reaction of the electrochemical active species in biofilms is pH dependent, and both electrons and protons are involved in the redox reactions.
Co-reporter:Tian Yuan;Yong Yuan;Fangbai Li;Zhi Liu
Journal of Soils and Sediments 2011 Volume 11( Issue 3) pp:467-473
Publication Date(Web):2011 April
DOI:10.1007/s11368-010-0332-1
The evaluation of the electron transfer capacities (ETC) of DOM is important to understand their roles in microbial activity, pollution degradation, and metal mobility. Those currently used methods to quantify ETC, such as Zn and Fe3+ assays, are normally time consuming and usually require experience and skills to achieve reproducible results. The aim of this paper is to develop a rapid and simple approach to accurately and directly quantify the ETC of DOM.DOM was extracted from sewage sludge compost. Cycle voltammetry (CV) was used to investigate the redox behavior of DOM derived from sludge compost. Chronoamperometry (CA) was employed to study the electron-accepting capacities (EAC) and electron-donating capacities (EDC) by applying fixed positive or negative potentials to a working electrode in a conventional three-electrode cell. For comparison, the EAC and EDC of DOM were also determined by chemical methods using Zn as the reductant and Fe3+ as the oxidant. The reversible electron transfer of DOM was studied electrochemically by CA with a multi-potential step technique.The CV of sludge DOM displayed that a couple of quasi-reversible redox peaks with a formal potential of –0.866 V (vs. Ag/AgCl), demonstrating that the DOM was capable of reversibly transferring electrons. The value of EAC was determined by CA to be 361.6 μmole− (g C)−1 at a potential of −0.6 V (vs. Ag/AgCl), and the value of initial EDC was 5.0 μmole− (g C)−1 at a potential of +0.4 V (vs. Ag/AgCl). Both the values of EAC and EDC depended on the applied potentials on the working electrode. The results determined by the proposed method were comparable with those by using chemical methods.A rapid electrochemical approach was employed to investigate the EAC and EDC of DOM extracted from sewage sludge compost. The acquired values of EAC and EDC were comparable with those measured by chemical methods using zinc as the reductant and ferric iron as the oxidant. The determination could be completed in tens of seconds, which was faster and more direct than conventional chemical methods.
Co-reporter:Chen Ma;Yueqiang Wang;Li Zhuang;Deyin Huang
Journal of Soils and Sediments 2011 Volume 11( Issue 6) pp:923-929
Publication Date(Web):2011 September
DOI:10.1007/s11368-011-0368-x
The anaerobic degradation of polycyclic aromatic hydrocarbons (PAHs) has great significance to PAHs’ natural attenuation in contaminated sites. Previous studies mainly focused on anaerobic PAH degradation by mixed cultures with nitrate, sulfate, or Fe(III) oxides as electron acceptors, and the roles of pure cultures in the process was rarely reported. The aim of this paper is to isolate a pure culture that is capable of degrading phenanthrene anaerobically with anthraquinone-2,6-disulphonate (AQDS) as the sole electron acceptor and evaluate its environmental functions.A strain of pure culture was isolated from anodic solution of a microbial fuel cell via enrichment procedure with phenanthrene and AQDS under anaerobic conditions. Using the single colony isolation technique, a distinct colony was obtained and identified by the phenotypic and phylogenetic analysis. Its ability to reduce AQDS and degrade phenanthrene was conducted in serum bottles by standard anaerobic techniques (purged with 80% N2−20% CO2). The concentration of AH2QDS and fructose was quantified by UV-vis spectrophotometer at 450 and 210 nm, respectively. Cells number was determined by direct plate counting on aerobic LB agar medium. The concentration of phenanthrene was determined using HPLC.Strain PAH-1 was identified as Pseudomonas aeruginosa. It could oxidize fructose or glucose to reduce AQDS and can support microbial growth by conserving energy from fructose to AQDS. It has the ability to degrade phenanthrene directly with AQDS as the sole electron acceptor (46.5% removal), and the microbial process may be AQDS dependent. The addition of small organic substances (fructose) could enhance the anaerobic biodegradation of phenanthrene from 46.5% to 56.7%. The anaerobic degradation of phenanthrene fits the pseudo-first-order kinetics, giving the rate constants of 0.0233/day (R2 = 0.934) and 0.0328/day (R2 = 0.933) for non-fructose set and fructose set, respectively.We successfully isolated a facultative anaerobe, P. aeruginosa strain PAH-1. This study was the first paper reporting that a pure culture (strain PAH-1) has the ability to anaerobically degrade phenanthrene with AQDS as the sole electron acceptor. The finding also explores the environmental significance of the Pseudomonas genus.
Co-reporter:Yong Yuan, Shungui Zhou, Li Zhuang
Journal of Power Sources 2010 Volume 195(Issue 11) pp:3490-3493
Publication Date(Web):1 June 2010
DOI:10.1016/j.jpowsour.2009.12.026
A polypyrrole/carbon black (Ppy/C) composite has been employed as an electrocatalyst for the oxygen reduction reaction (ORR) in an air-cathode microbial fuel cell (MFC). The electrocatalytic activity of the Ppy/C is evaluated toward the oxygen reduction using cyclic voltammogram and linear sweep voltammogram methods. In comparison with that at the carbon black electrode, the peak potential of the ORR at the Pp/C electrode shifts by approximate 260 mV towards positive potential, demonstrating the electrocatalytic activity of Ppy toward ORR. Additionally, the results of the MFC experiments show that the Ppy/C is well suitable to fully substitute the traditional cathode materials in MFCs. The maximum power density of 401.8 mW m−2 obtained from the MFC with a Ppy/C cathode is higher than that of 90.9 mW m−2 with a carbon black cathode and 336.6 mW m−2 with a non-pyrolysed FePc cathode. Although the power output with a Ppy/C cathode is lower than that with a commercial Pt cathode, the power per cost of a Ppy/C cathode is 15 times greater than that of a Pt cathode. Thus, the Ppy/C can be a good alternative to Pt in MFCs due to the economic advantage.
Co-reporter:Li Zhuang, Shungui Zhou, Yongtao Li, Tinglin Liu, Deyin Huang
Journal of Power Sources 2010 Volume 195(Issue 5) pp:1379-1382
Publication Date(Web):1 March 2010
DOI:10.1016/j.jpowsour.2009.09.011
This study reports that Fenton's reaction is capable of facilitating cathodic reaction and thus increasing the current output in microbial fuel cells (MFCs). The hydroxyl radicals (OH) produced via Fenton's reaction are demonstrated to be vital to the enhancement of electricity generation in MFCs. In a two-chamber MFC employing expanded polytetrafluoroethylene (e-PTFE) laminated cloth as a separator, the power output is enhanced approximately four times with Fenton's reaction. However, the enhancement lasts only a short time period due to the rapid consumption of Fenton's reagents. To overcome this problem, a Fe@Fe2O3/carbon felt (CF) composite cathode is made, which results in a greater and, more importantly, sustainable power output. In the composite cathode, Fe@Fe2O3 functions as a controllably releasing Fenton iron reagent and CF functions as an air-fed cathode to electro-generate H2O2. This newly developed MFC with a Fenton system can ensure a continuous high power output, and also provides a potential solution to the simultaneous electricity generation and degradation of recalcitrant contaminants.
Co-reporter:De-Yin Huang;Li Zhuang;Wei-Dong Cao;Wei Xu
Journal of Soils and Sediments 2010 Volume 10( Issue 4) pp:722-729
Publication Date(Web):2010 May
DOI:10.1007/s11368-009-0161-2
Land utilization of sewage sludge and sludge compost is a common practice in many countries. Soils amended with sewage sludge and sludge compost display different physicochemical properties, especially in terms of dissolved organic matter (DOM) composition that affects the electron-donating capacity (EDC) of DOM in soils. The aim of this paper was to compare the EDC of DOM derived from sewage sludge and sludge compost for enhancing Fe(III) bioreduction. It is expected that this research could be helpful for further understanding of soil remediation in the future.Sludge and compost DOM were extracted from sewage sludge and sludge compost, respectively. Fractionation, CHNO/S analysis, Fourier-transform infrared and ultraviolet-visible spectroscopy, and cyclic voltammetry were then used to determine the degree of aromaticity and humification in the samples. To determine if their EDC was altered during composting, samples were reduced by the humic-reducing bacterium, Shewanella cinica D14T, after which their EDC values were determined. The initial and potential EDC values of the samples were measured using FeCl3/Fe(citrate) as an electron acceptor. The insoluble Fe(III) oxide reduction by strain D14T was mediated by DOM.Both sludge and compost DOM contained redox-active functional groups that could shuttle electrons to insoluble Fe(III) oxide and accelerate Fe(III) bioreduction. When FeCl3 was used as an oxidizing agent, their potential EDC reached 0.25 and 0.50 meq/(mg C), respectively. In addition, their electron transfer ability could be recycled.The degree of humification of DOM increased during sludge composting, which resulted in the EDC of compost DOM being greater than that of sludge DOM. Furthermore, the rate of Fe(III) bioreduction mediated by DOM could be accelerated under anaerobic conditions, which has important implications for soil biogeochemistry because it may accelerate the rate of some kinds of toxic metals and recalcitrant organic pollutants transformation or degradation.
Co-reporter:LiFang Deng;FangBai Li;DeYin Huang;JinRen Ni
Science Bulletin 2010 Volume 55( Issue 1) pp:99-104
Publication Date(Web):2010 January
DOI:10.1007/s11434-009-0563-y
In microbial fuel cell (MFC), the rate of electron transfer to anode electrode is a key intrinsic limiting factor on the power output of MFCs. Using Klebsiella pneumoniae (K. pneumoniae) strain L17 as biocatalyst, we studied the mechanism of electron shuttle via self-producing mediator in a cubic air-chamber MFC. To eliminate the influence of biofilm mechanism, the anode electrode was coated with microfiltration membrane (0.22 μm). Data showed that the microfiltration membrane coated and uncoated MFCs achieved the maximum voltage outputs of 316.2 and 426.2 mV after 270 and 120 h, respectively. When the medium was replaced in MFCs that had the highest power generation, the power output dropped by 62.1% and 8.8%, and required 120 and 48 h to resume the original level in the coated and uncoated MFCs, respectively. The results suggested an electron-shuttle mechanism rather than biofilm mechanism was responsible for electricity generation in the membrane coated MFC. Cyclic voltammetric measurements demonstrated the presence of an electrochemical active compound produced by K. pneumoniae strain L17, which was identified to be 2,6-di-tert-butyl-p-benzoquinon (2,6-DTBBQ) by GC-MS. 2,6-DTBBQ, as a recyclable electron shuttle, could transfer electrons between K. pneumoniae L17 and the anode electrode.
Co-reporter:Li Zhuang, Shungui Zhou
Electrochemistry Communications 2009 Volume 11(Issue 5) pp:937-940
Publication Date(Web):May 2009
DOI:10.1016/j.elecom.2009.02.027
This study presented a new design of scalable, air-cathode microbial fuel cell (MFC) stack that shared a common fuel feed passage. As two individual cells were electrically connected in series by metal wires and hydraulically joined by conductive substrate flow, the performance degradation phenomenon was observed. The open circuit voltage (OCV) and low current behavior of stacked MFC were lower than should be expected. This energy loss was proposed to be a consequence of parasitic current flow due to the substrate cross-conduction effect and can be likely minimized through controlling the distance between the anode electrodes or/and the cross-sectional area of substrate flow. The unique and simple water distribution system of the tubular MFC stack would contribute to the further scale-up and implementation of MFC technologies, especially for wastewater treatment.
Co-reporter:Li Zhuang, Shungui Zhou, Yueqiang Wang, Chengshuai Liu, Shu Geng
Biosensors and Bioelectronics 2009 Volume 24(Issue 12) pp:3652-3656
Publication Date(Web):15 August 2009
DOI:10.1016/j.bios.2009.05.032
One of the main challenges for scaling up microbial fuel cell (MFC) technologies is developing low-cost cathode architectures that can generate high power output. This study developed a simple method to convert non-conductive material (canvas cloth) into an electrically conductive and catalytically active cloth cathode assembly (CCA) in one step. The membrane-less CCA was simply constructed by coating the cloth with conductive paint (nickel-based or graphite-based) and non-precious metal catalyst (MnO2). Under the fed-batch mode, the tubular air-chamber MFCs equipped with Ni-CCA and graphite-CCA generated the maximum power densities of 86.03 and 24.67 mW m−2 (normalized to the projected cathode surface area), or 9.87 and 2.83 W m−3 (normalized to the reactor liquid volume), respectively. The higher power output of Ni-CCA-MFC was associated with the lower volume resistivity of Ni-CCA (1.35 × 10−2 Ω cm) than that of graphite-CCA (225 × 10−2 Ω cm). At an external resistance of 100 Ω, Ni-CCA-MFC and graphite-CCA-MFC removed approximately 95% COD in brewery wastewater within 13 and 18 d, and achieved coulombic efficiencies of 30.2% and 19.5%, respectively. The accumulated net water loss through the cloth by electro-osmotic drag exhibited a linear correlation (R2 = 0.999) with produced coulombs. With a comparable power production, such CCAs only cost less than 5% of the previously reported membrane cathode assembly. The new cathode configuration here is a mechanically durable, economical system for MFC scalability.
Co-reporter:Lixia Zhang, Chengshuai Liu, Li Zhuang, Weishan Li, Shungui Zhou, Jintao Zhang
Biosensors and Bioelectronics 2009 Volume 24(Issue 9) pp:2825-2829
Publication Date(Web):15 May 2009
DOI:10.1016/j.bios.2009.02.010
In this paper, three manganese dioxide materials, α-MnO2, β-MnO2, γ-MnO2 were tested as alternative cathodic catalysts to platinum (Pt) in air-cathode microbial fuel cells (MFCs). Prepared via hydrothermal method, the manganese dioxides were characterized by X-ray powder diffraction patterns (XRD), the Brunauer–Emmett–Teller (BET) method and their average oxidation states (AOS) were determined by the potential voltammetric titration method. The electro-catalytic activity of MnO2 in neutral pH solution was determined by linear sweep voltammetry (LSV) and the results showed that all manganese dioxides can catalyze oxygen reduction reaction (ORR) in neutral medium with different catalytic activities. β-MnO2 appeared to hold the highest catalytic activity due to its highest BET surface area and AOS. β-MnO2 was further used as cathode catalyst in both cube and tube air-cathode MFCs, in which using Klebsiella pneumoniae (K. pneumoniae) biofilm as biocatalyst and utilizing glucose as a substrate in the anode chamber. It was found that tube MFC produced higher output power, with the maximum volumetric power density of 3773 ± 347 mW/m3, than cube MFC. This study suggests that using β-MnO2 instead of Pt could potentially improve the feasibility of scaling up MFC designs for real applications by lowering production cost.
Co-reporter:XiaoMin Li;YongTao Li;FangBai Li;ChunHua Feng
Science Bulletin 2009 Volume 54( Issue 16) pp:2800-2804
Publication Date(Web):2009 August
DOI:10.1007/s11434-009-0475-x
The interactively interfacial reactions between the iron-reducing bacterium (Shewanella decolorationis, S12) and iron oxide (α-FeOOH) were investigated to determine reductive dechlorination transformation of chlorinated organic compounds (chloroform and pentachlorophenol). The results showed that the interactive system of S12+ α-FeOOH exhibited relatively high dechlorination rate. By comparison, the S12 biotic system alone had no obvious dechlorination, and the α-FeOOH abiotic system showed low dechlorination rate. The enhanced dechlorination of chloroform and pentachlorophenol in the interactive system of S12+α-FeOOH was derived from the promoted generation of adsorbed Fe(II) by S12. A decrease in redox potential of the Fe(III)/Fe(II) couple in the interactive reaction system was determined by cyclic voltammetry. Our results will give new insight into interactively interfacial reaction between iron-reducing bacterium and iron oxides for degradation of chlorinated organic compounds under anaerobic condition.
Co-reporter:Guiqin Yang, Lingyan Huang, Lexing You, Li Zhuang, Shungui Zhou
Electrochemistry Communications (April 2017) Volume 77() pp:
Publication Date(Web):April 2017
DOI:10.1016/j.elecom.2017.03.004
•Geobacter soli biofilms could catalyze both anodic and cathodic reactions in bioelectrochemical systems.•In the cathodic reaction, nitrate can be reduced via a truncated denitrification pathway, with nitrous oxide as end product.•Different electron transfer conduits are used for G. soli to transfer electrons to and from electrodes.Few electroactive bacteria have shown the capacity of exchanging electrons with electrode in both directions, and the mechanisms of such bidirectional electron transfer remain uncertain hitherto. In this study, we demonstrate that Geobacter soli biofilms could directly donate electrons to and accept electrons from graphite electrode. Under anodic conditions, G. soli oxidizes acetate to generate current, and under cathodic conditions, nitrate is reduced by a truncated denitrification pathway with nitrous oxide as end product. Cyclic voltammetry, differential pulse voltammetry and electrochemical in situ FTIR spectra demonstrate that distinct external membrane redox systems exist in the anode and cathode biofilms, which supports the conclusion that G. soli uses different electron transfer conduits for bidirectional electron transfer. These results expand the horizon of bidirectional electron transfer mechanisms, meanwhile this study represents a first report that Geobacter species might utilize electrode as electron donor for incomplete denitrification.
Co-reporter:Chen Ma, Guiqin Yang, Qun Zhang, Li Zhuang, Shungui Zhou
Journal of Biotechnology (10 May 2016) Volume 225() pp:59-60
Publication Date(Web):10 May 2016
DOI:10.1016/j.jbiotec.2016.03.029
•Thauera humireducens SgZ-1 was a novel humus-reducing bacterium, isolated from the anode biofilm of a sediment microbial fuel cell.•Strain SgZ-1 was able to reduce humus, Fe(III) species and nitrate in anerobic conditions.•Strain SgZ-1 has vast potential for application in environmental remediation and wastewater treatment.•The genome sequence of strain SgZ-1 will help to understand the genetics basis of metobolism of electron donors and acceptors for environmental remediation and wastewater treatment.Thauera humireducens SgZ-1T (KACC 16524T = CCTCC M2011497T), isolated from the anode biofilm of a microbial fuel cell, is able to grow under anaerobic conditions via the oxidation of various organic compounds coupled to the reduction of humus, Fe(III) species and nitrate. Addtionally, the strain has the ability to produce exopolysaccharide (EPS). Here, we report the complete genome sequence of T. humiruducens SgZ-1T, which is relevant to metabolism of electron donors and acceptors for environmental remediation and wastewater treatment.
Co-reporter:Yong Yuan, Ting Liu, Peng Fu, Jiahuan Tang and Shungui Zhou
Journal of Materials Chemistry A 2015 - vol. 3(Issue 16) pp:NaN8482-8482
Publication Date(Web):2015/03/11
DOI:10.1039/C5TA00458F
Conversion of sewage sludge (SS) into value-added biochar has garnered increasing attention due to its potential applications as a soil amendment and pollutant adsorbent. In this study, we propose a new application of the SS-derived biochar as an advanced bifunctional electrode material (anode and cathode) in microbial fuel cells (MFCs). To function as an anode, the SS amended with various amounts of coconut shell was pressed into a mold and then converted into SS-derived carbon monoliths (SMs) by heat treatment. Meanwhile, powdered SMs (PSMs) were used as the catalysts for oxygen reduction in the cathodes of the MFCs. The maximum power density of 969 ± 28 mW m−2 was achieved from the MFC with a SM anode and a PSM cathode, which was ca. 2.4 times that of the MFC with a graphite anode and a Pt cathode. The enhanced electrical conductivity of the SMs caused by amending the coconut shell resulted in the enrichment of exoelectrogens and the decrease in electron transfer resistance, which were responsible for the excellent performances of the as-prepared electrodes. This study suggests a promising method to convert SS into bifunctional electrode materials, offering a new opportunity for value-added applications of SS-derived biochar.
Co-reporter:Junhua Chen, Junlin Wen, Guiqin Yang and Shungui Zhou
Chemical Communications 2015 - vol. 51(Issue 62) pp:NaN12376-12376
Publication Date(Web):2015/06/23
DOI:10.1039/C5CC04347F
A label-free and enzyme-free three-way G-quadruplex junction sensing system for the amplified detection of 17β-estradiol has been constructed by the ingenious coupling of split G-quadruplex DNAzyme with toehold-mediated strand displacement. The biosensor is ultrasensitive, enabling the visual detection of 17β-estradiol concentrations as low as 1 fM without instrumentation.
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