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Su H, Yan X, Zhao Q, Liao C, Tian L, Wang Z, Wan Y, Li N, Wang X. Layered Design of a Highly Repeatable Electroactive Biofilm for a Standardized Biochemical Oxygen Demand Sensor. ACS Sens 2023; 8:2383-2390. [PMID: 37249569 DOI: 10.1021/acssensors.3c00583] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Microbial electrochemical sensors are promising to monitor bioavailable organics in real environments, but their application is restricted by the unpredictable performance of the electroactive biofilm (EAB), which is randomly acclimated from environmental microflora. With a long-term stable EAB as a template, we successfully designed EAB (DEAB) by the sequential growth of Geobacter anodireducens and automatched microbes, achieving a reproducible high current than those naturally acclimated from wastewater (NEAB). Pre-inoculation of planktonic aerobes as oxygen bioscavengers was necessary to ensure the colonization of Geobacter in the inner layer, and the abundant Geobacter (50%) in DEAB guaranteed 4 times higher current density with a 15-fold smaller variation among 20 replicates than those of NEAB. The sensor constructed with DEAB exhibited a shorter measuring time and a precise biochemical oxygen demand (BOD) measurement with acetate, real domestic wastewater, and supernatant of anaerobic digestion. Here, we for the first time proposed an applicable strategy to standardize EABs for BOD sensors, which is also crucial to ensure a stable performance of all bioelectrochemical technologies.
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Affiliation(s)
- Huijuan Su
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Xuejun Yan
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Qian Zhao
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Chengmei Liao
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Lili Tian
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Ziyuan Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Yuxuan Wan
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Nan Li
- School of Environmental Science and Engineering, Tianjin University, No. 35 Yaguan Road, Jinnan District, Tianjin 300350, China
| | - Xin Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
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Aguilar-Torrejón JA, Balderas-Hernández P, Roa-Morales G, Barrera-Díaz CE, Rodríguez-Torres I, Torres-Blancas T. Relationship, importance, and development of analytical techniques: COD, BOD, and, TOC in water—An overview through time. SN APPLIED SCIENCES 2023. [DOI: 10.1007/s42452-023-05318-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
AbstractAnalytical techniques to measure organic matter in water, such as Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5), and Total Organic Carbon (TOC) are widely used. Modifications have been proposed to make them faster, more sensitive, and more environmentally friendly. The purpose of producing a review over some time is to show the changes made on the standardized methods of each of these techniques, and to highlight the relationship between them in the process of ascertaining organic matter in water. Modifications to techniques COD and BOD entail several factors that need to be considered, namely: time, miniaturization, sensitivity, use of environmentally friendly reagents. Changes to TOC are focused on detection systems. Despite the advantages obtained by the modified techniques, traditional methods continue to be widely used, in most cases due to the lack of standardization of the new methods.
Graphic Abstract
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Arlyapov VA, Plekhanova YV, Kamanina OA, Nakamura H, Reshetilov AN. Microbial Biosensors for Rapid Determination of Biochemical Oxygen Demand: Approaches, Tendencies and Development Prospects. BIOSENSORS 2022; 12:842. [PMID: 36290979 PMCID: PMC9599453 DOI: 10.3390/bios12100842] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/23/2022] [Accepted: 10/01/2022] [Indexed: 06/16/2023]
Abstract
One of the main indices of the quality of water is the biochemical oxygen demand (BOD). A little over 40 years have passed since the practical application of the first microbial sensor for the determination of BOD, presented by the Japanese professor Isao Karube. This time span has brought new knowledge to and practical developments in the use of a wide range of microbial cells based on BOD biosensors. At present, this field of biotechnology is becoming an independent discipline. The traditional BOD analysis (BOD5) has not changed over many years; it takes no less than 5 days to carry out. Microbial biosensors can be used as an alternative technique for assessing the BOD attract attention because they can reduce hundredfold the time required to measure it. The review examines the experience of the creation and practical application of BOD biosensors accumulated by the international community. Special attention is paid to the use of multiple cell immobilization methods, signal registration techniques, mediators and cell consortia contained in the bioreceptor. We consider the use of nanomaterials in the modification of analytical devices developed for BOD evaluation and discuss the prospects of developing new practically important biosensor models.
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Affiliation(s)
- Vyacheslav A. Arlyapov
- Laboratory of Biologically Active Compounds and Biocomposites, Federal State Budgetary Educational Establishment of Higher Education “Tula State University”, 300012 Tula, Russia
| | - Yulia V. Plekhanova
- Pushchino Center for Biological Research of the Russian Academy of Sciences, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 142290 Pushchino, Russia
| | - Olga A. Kamanina
- Laboratory of Biologically Active Compounds and Biocomposites, Federal State Budgetary Educational Establishment of Higher Education “Tula State University”, 300012 Tula, Russia
| | - Hideaki Nakamura
- Department of Liberal Arts, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo 192-0982, Japan
| | - Anatoly N. Reshetilov
- Pushchino Center for Biological Research of the Russian Academy of Sciences, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 142290 Pushchino, Russia
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Kurbanalieva S, Arlyapov V, Kharkova A, Perchikov R, Kamanina O, Melnikov P, Popova N, Machulin A, Tarasov S, Saverina E, Vereshchagin A, Reshetilov A. Electroactive Biofilms of Activated Sludge Microorganisms on a Nanostructured Surface as the Basis for a Highly Sensitive Biochemical Oxygen Demand Biosensor. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22166049. [PMID: 36015810 PMCID: PMC9414782 DOI: 10.3390/s22166049] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 05/04/2023]
Abstract
The possibility of the developing a biochemical oxygen demand (BOD) biosensor based on electroactive biofilms of activated sludge grown on the surface of a graphite-paste electrode modified with carbon nanotubes was studied. A complex of microscopic methods controlled biofilm formation: optical microscopy with phase contrast, scanning electron microscopy, and laser confocal microscopy. The features of charge transfer in the obtained electroactive biofilms were studied using the methods of cyclic voltammetry and electrochemical impedance spectroscopy. The rate constant of the interaction of microorganisms with the extracellular electron carrier (0.79 ± 0.03 dm3(g s)-1) and the heterogeneous rate constant of electron transfer (0.34 ± 0.02 cm s-1) were determined using the cyclic voltammetry method. These results revealed that the modification of the carbon nanotubes' (CNT) electrode surface makes it possible to create electroactive biofilms. An analysis of the metrological and analytical characteristics of the created biosensors showed that the lower limit of the biosensor based on an electroactive biofilm of activated sludge is 0.41 mgO2/dm3, which makes it possible to analyze almost any water sample. Analysis of 12 surface water samples showed a high correlation (R2 = 0.99) with the results of the standard method for determining biochemical oxygen demand.
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Affiliation(s)
- Saniyat Kurbanalieva
- Laboratory of Biologically Active Compounds and Biocomposites, Tula State University, Lenin Pr. 92, Tula 300012, Russia
| | - Vyacheslav Arlyapov
- Laboratory of Biologically Active Compounds and Biocomposites, Tula State University, Lenin Pr. 92, Tula 300012, Russia
- Correspondence:
| | - Anna Kharkova
- Laboratory of Biologically Active Compounds and Biocomposites, Tula State University, Lenin Pr. 92, Tula 300012, Russia
| | - Roman Perchikov
- Laboratory of Biologically Active Compounds and Biocomposites, Tula State University, Lenin Pr. 92, Tula 300012, Russia
| | - Olga Kamanina
- Laboratory of Biologically Active Compounds and Biocomposites, Tula State University, Lenin Pr. 92, Tula 300012, Russia
| | - Pavel Melnikov
- M. V. Lomonosov Institute of Fine Chemical Technologies, MIREA—Russian Technological University, Prosp. Vernadskogo 86, Moscow 119571, Russia
| | - Nadezhda Popova
- Federal State Budgetary Institution of Science Institute of Physical Chemistry and Electrochemistry of the Russian Academy of Sciences, Leninsky Prosp., 31 k. 4., Moscow 119071, Russia
| | - Andrey Machulin
- Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences—A Separate Subdivision of the FRC Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Prosp. Science 3, Pushchino 142290, Russia
| | - Sergey Tarasov
- Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences—A Separate Subdivision of the FRC Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Prosp. Science 3, Pushchino 142290, Russia
| | - Evgeniya Saverina
- N. D. Zelinsky Institute of Organic Chemistry, Leninsky Pr. 47, Moscow 119991, Russia
| | - Anatoly Vereshchagin
- N. D. Zelinsky Institute of Organic Chemistry, Leninsky Pr. 47, Moscow 119991, Russia
| | - Anatoly Reshetilov
- Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences—A Separate Subdivision of the FRC Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Prosp. Science 3, Pushchino 142290, Russia
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A Mediated BOD Biosensor Based on Immobilized B. Subtilis on Three-Dimensional Porous Graphene-Polypyrrole Composite. SENSORS 2017; 17:s17112594. [PMID: 29125543 PMCID: PMC5713028 DOI: 10.3390/s17112594] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 10/19/2017] [Accepted: 11/07/2017] [Indexed: 12/11/2022]
Abstract
We have developed a novel mediated biochemical oxygen demand (BOD) biosensor based on immobilized Bacillus subtilis (B. subtilis) on three-dimensional (3D) porous graphene-polypyrrole (rGO-PPy) composite. The 3D porous rGO-PPy composite was prepared using hydrothermal method following with electropolymerization. Then the 3D porous rGO-PPy composite was used as a support for immobilizing negatively charged B. subtilis denoted as rGO-PPy-B through coordination and electrostatic interaction. Further, the prepared rGO-PPy-B was used as a microbial biofilm for establishing a mediated BOD biosensor with ferricyanide as an electronic acceptor. The indirect determination of BOD was performed by electrochemical measuring ferrocyanide generated from a reduced ferricyanide mediator using interdigited ultramicroelectrode array (IUDA) as the working electrode. The experimental results suggested a good linear relationship between the amperometric responses and BOD standard concentrations from 4 to 60 mg/L, with a limit detection of 1.8 mg/L (S/N ≥ 3). The electrochemical measurement of real water samples showed a good agreement with the conventional BOD₅ method, and the good anti-interference as well as the long-term stability were well demonstrated, indicating that the proposed mediated BOD biosensor in this study holds a potential practical application of real water monitoring.
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Wang J, Li Y, Bian C, Tong J, Fang Y, Xia S. Ultramicroelectrode array modified with magnetically labeled Bacillus subtilis, palladium nanoparticles and reduced carboxy graphene for amperometric determination of biochemical oxygen demand. Mikrochim Acta 2016. [DOI: 10.1007/s00604-016-2055-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Pujol-Vila F, Vigués N, Guerrero-Navarro A, Jiménez S, Gómez D, Fernández M, Bori J, Vallès B, Riva M, Muñoz-Berbel X, Mas J. Paper-based chromatic toxicity bioassay by analysis of bacterial ferricyanide reduction. Anal Chim Acta 2016; 910:60-7. [DOI: 10.1016/j.aca.2016.01.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/21/2015] [Accepted: 01/03/2016] [Indexed: 11/25/2022]
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Prévoteau A, Geirnaert A, Arends JBA, Lannebère S, Van de Wiele T, Rabaey K. Hydrodynamic chronoamperometry for probing kinetics of anaerobic microbial metabolism--case study of Faecalibacterium prausnitzii. Sci Rep 2015; 5:11484. [PMID: 26127013 PMCID: PMC4486957 DOI: 10.1038/srep11484] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 05/12/2015] [Indexed: 01/26/2023] Open
Abstract
Monitoring in vitro the metabolic activity of microorganisms aids bioprocesses and enables better understanding of microbial metabolism. Redox mediators can be used for this purpose via different electrochemical techniques that are either complex or only provide non-continuous data. Hydrodynamic chronoamperometry using a rotating disc electrode (RDE) can alleviate these issues but was seldom used and is poorly characterized. The kinetics of Faecalibacterium prausnitzii A2-165, a beneficial gut microbe, were determined using a RDE with riboflavin as redox probe. This butyrate producer anaerobically ferments glucose and reduces riboflavin whose continuous monitoring on a RDE provided highly accurate kinetic measurements of its metabolism, even at low cell densities. The metabolic reaction rate increased linearly over a broad range of cell concentrations (9 × 10(4) to 5 × 10(7) cells.mL(-1)). Apparent Michaelis-Menten kinetics was observed with respect to riboflavin (KM = 6 μM; kcat = 5.3 × 10(5) s(-1), at 37 °C) and glucose (KM = 6 μM; kcat = 2.4 × 10(5) s(-1)). The short temporal resolution allows continuous monitoring of fast cellular events such as kinetics inhibition with butyrate. Furthermore, we detected for the first time riboflavin reduction by another potential probiotic, Butyricicoccus pullicaecorum. The ability of the RDE for fast, accurate, simple and continuous measurements makes it an ad hoc tool for assessing bioprocesses at high resolution.
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Affiliation(s)
- Antonin Prévoteau
- Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | - Annelies Geirnaert
- Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | - Jan B A Arends
- Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | - Sylvain Lannebère
- University of Coimbra, Department of Electrical Engineering - Instituto de Telecomunicações, Coimbra 3030-290, Portugal
| | - Tom Van de Wiele
- Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | - Korneel Rabaey
- Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
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Fast and sensitive optical toxicity bioassay based on dual wavelength analysis of bacterial ferricyanide reduction kinetics. Biosens Bioelectron 2015; 67:272-9. [DOI: 10.1016/j.bios.2014.08.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 07/22/2014] [Accepted: 08/07/2014] [Indexed: 10/24/2022]
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11
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Liu L, Bai L, Yu D, Zhai J, Dong S. Biochemical oxygen demand measurement by mediator method in flow system. Talanta 2015; 138:36-39. [PMID: 25863368 DOI: 10.1016/j.talanta.2015.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Revised: 01/28/2015] [Accepted: 02/01/2015] [Indexed: 11/15/2022]
Abstract
Using mediator as electron acceptor for biochemical oxygen demand (BOD) measurement was developed in the last decade (BODMed). However, until now, no BOD(Med) in a flow system has been reported. This work for the first time describes a flow system of BOD(Med) method (BOD(Med)-FS) by using potassium ferricyanide as mediator and carbon fiber felt as substrate material for microbial immobilization. The system can determine the BOD value within 30 min and possesses a wider analytical linear range for measuring glucose-glutamic acid (GGA) standard solution from 2 up to 200 mg L(-1) without the need of dilution. The analytical performance of the BOD(Med)-FS is comparable or better than that of the previously reported BOD(Med) method, especially its superior long-term stability up to 2 months under continuous operation. Moreover, the BOD(Med)-FS has same determination accuracy with the conventional BOD5 method by measuring real samples from a local wastewater treatment plant (WWTP).
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Affiliation(s)
- Ling Liu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Lu Bai
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Dengbin Yu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Junfeng Zhai
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Shaojun Dong
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
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Cheng L, Quek SB, Cord-Ruwisch R. Hexacyanoferrate-adapted biofilm enables the development of a microbial fuel cell biosensor to detect trace levels of assimilable organic carbon (AOC) in oxygenated seawater. Biotechnol Bioeng 2014; 111:2412-20. [PMID: 24942462 DOI: 10.1002/bit.25315] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 06/06/2014] [Accepted: 06/10/2014] [Indexed: 02/04/2023]
Abstract
A marine microbial fuel cell (MFC) type biosensor was developed for the detection of assimilable organic carbon (AOC) in ocean water for the purpose of online water quality monitoring for seawater desalination plants prone to biofouling of reverse osmosis (RO) membranes. The anodophilic biofilm that developed on the graphite tissue anode could detect acetate as the model AOC to concentrations as low as 5 µM (120 µg/L of AOC), which is sufficiently sensitive as an online biofouling risk sensor. Although the sensor was operated at a higher (+200 ± 10 mV) than the usual (-300 mV) anodic potential, the presence of oxygen completely suppressed the electrical signal. In order to overcome this outcompeting effect of oxygen over the anode as electron acceptor by the bacteria, hexacyanoferrate (HCF(III)) was found to enable the development of an adapted biofilm that transferred electrons to HCF(III) rather than oxygen. As the resultant of the reduced HCF(II) could readily transfer electrons to the anode while being re-oxidised to HCF(III), the marine MFC biosensor developed could be demonstrated to work in the presence of oxygen unlike traditional MFC. The possibility of operating the marine MFC in batch or continuous (in-line) mode has been explored by using coulombic or potentiometric interpretation of the signal.
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Affiliation(s)
- Liang Cheng
- School of Engineering and Information Technology, Murdoch University, 90, South Street, Perth, West Australia, 6150, Australia.
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13
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Yip NC, Rawson FJ, Tsang CW, Mendes PM. Real-time electrocatalytic sensing of cellular respiration. Biosens Bioelectron 2014; 57:303-9. [PMID: 24607581 PMCID: PMC3990025 DOI: 10.1016/j.bios.2014.01.059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 01/17/2014] [Accepted: 01/28/2014] [Indexed: 11/09/2022]
Abstract
In the present work we develop a real-time electrochemical mediator assay to enable the assessment of cell numbers and chemical toxicity. This allowed us to monitor metabolism down to a single cell in a low cost easy to use rapid assay which is not possible with current technology. The developed assay was based on the determination of oxygen. This was made possible via the use of electrochemical mediator ferrocene carboxylic acid (FcA). The FcA showed distinctive catalytic properties in interacting with reactive oxygen species generated from oxygen when compared to ferrocene methanol (FcMeOH). A deeper insight into the chemistry controlling this behaviour is provided. The behaviour is then taken advantage of to develop a cellular aerobic respiration assay. We describe the properties of the FcA system to detect, in real-time, the oxygen consumption of Escherichia coli DH5-α (E. coli). We demonstrated that the FcA-based oxygen assay is highly sensitive, and using a population of cells, oxygen consumption rates could be calculated down to a single cell level. More importantly, the results can be accomplished in minutes, considerably outperforming current commercially available biooxygen demand assays. The developed assay is expected to have a significant impact in diverse fields and industries, ranging from environmental toxicology through to pharmaceutical and agrochemical industries.
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Affiliation(s)
- Nga-Chi Yip
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Frankie J Rawson
- Laboratory of Biophysics and Surface Analysis, School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Chi Wai Tsang
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Paula M Mendes
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
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Jordan MA, Welsh DT, Teasdale PR. Ubiquity of activated sludge ferricyanide-mediated BOD methods: a comparison of sludge seeds across wastewater treatment plants. Talanta 2014; 125:293-300. [PMID: 24840446 DOI: 10.1016/j.talanta.2014.03.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 02/26/2014] [Accepted: 03/05/2014] [Indexed: 10/25/2022]
Abstract
Many studies have described alternatives to the BOD5 standard method, with substantial decreases in incubation time observed. However, most of these have not maintained the features that make the BOD5 assay so relevant - a high level of substrate bio-oxidation and use of wastewater treatment plant (WWTP) sludge as the biocatalyst. Two recently described ferricyanide-mediated (FM)-BOD assays, one for trade wastes and one for WWTP influents and treated effluents, satisfy these criteria and were investigated further here for their suitability for use with diverse biocatalysts. Both FM-BOD assays responded proportionately to increasing substrate concentration with sludges from 11 different WWTPs and temporally (months to years) using sludges from a single WWTP, confirming the broad applicability of both assays. Sludges from four WWTPs were selected as biocatalysts for each FM-BOD assay to compare FM-BOD equivalent values with BOD5 (three different sludge seeds) measurements for 12 real wastewater samples (six per assay). Strong and significant relationships were established for both FM-BOD assays. This study has demonstrated that sludge sourced from many WWTPs may be used as the biocatalyst in either FM-BOD assay, as it is in the BOD5 assay. The industry potential of these findings is substantial given the widespread use of the BOD5 assay, the dramatically decreased incubation period (3-6h) and the superior analytical range of both assays compared to the standard BOD5 assay.
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Affiliation(s)
- Mark A Jordan
- Environmental Futures Centre, Griffith University, Gold Coast Campus, Qld 4222, Australia; School of Environment, Griffith University, Gold Coast Campus, Qld 4222, Australia
| | - David T Welsh
- Environmental Futures Centre, Griffith University, Gold Coast Campus, Qld 4222, Australia.
| | - Peter R Teasdale
- Environmental Futures Centre, Griffith University, Gold Coast Campus, Qld 4222, Australia
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Thorne RJ, Hu H, Schneider K, Cameron PJ. Trapping of redox-mediators at the surface of Chlorella vulgaris leads to error in measurements of cell reducing power. Phys Chem Chem Phys 2014; 16:5810-6. [PMID: 24535230 DOI: 10.1039/c3cp54938k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reduction of the redox mediator ferricyanide, [Fe(CN)6](3-), by a range of algal and bacterial species, is frequently measured to probe plasma membrane ferrireductase activity or to quantify the reducing power of algal/bacterial biofilms and suspensions. In this study we have used rotating disk electrochemistry (RDE) to investigate the reduction of ferricyanide by the model organism Chlorella vulgaris. Importantly, we have seen that the diffusion limited current due to the oxidation of ferrocyanide, [Fe(CN)6](4-), at the electrode decreased linearly as C. vulgaris was added to the solution, even though in a pure ferrocyanide solution the algae are not able to reduce the mediator further and are simply spectator 'particles'. We attribute this effect to trapping of ferrocyanide at the cell surface, with up to 14% of the ferrocyanide missing from the solution at the highest cell concentration. The result has important implications for all techniques that use electrochemistry and other concentration dependent assays (e.g. fluorescence and colourimetry) to monitor ferrocyanide concentrations in the presence of both biofilms and cell suspensions. Analyte trapping could lead to a substantial underestimation of the concentration of reduced product.
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Affiliation(s)
- Rebecca J Thorne
- Department of Chemistry, University of Bath, 1 South, BA2 7AY, UK.
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