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Vassilev I, Rinta-Kanto JM, Kokko M. Comparing the performance of fluidized and fixed granular activated carbon beds as cathodes for microbial electrosynthesis of carboxylates from CO 2. BIORESOURCE TECHNOLOGY 2024; 403:130896. [PMID: 38795921 DOI: 10.1016/j.biortech.2024.130896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 05/22/2024] [Accepted: 05/23/2024] [Indexed: 05/28/2024]
Abstract
Microbial electrosynthesis (MES) can use renewable electricity to power microbial conversion of carbon dioxide (CO2) into carboxylates. To ensure high productivities in MES, good mass transfer must be ensured, which could be accomplished with fluidization of granular activated carbon (GAC). In this study, fluidized and fixed GAC bed cathodes were compared. Acetate production rate and current density were 42 % and 47 % lower, respectively, in fluidized than fixed bed reactors. Although similar microbial consortium dominated by Eubacterium and Proteiniphilum was observed, lowest biomass quantity was measured with fixed GAC bed indicating higher specific acetate production rates compared to fluidized GAC bed. Furthermore, charge efficiency was the highest and charge recovery in carboxylates the lowest in fixed GAC beds indicating enhanced hydrogen evolution and need for enhancing CO2 feeding to enable higher production rates of acetate. Overall, fixed GAC beds have higher efficiency for acetate production in MES than fluidized GAC beds.
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Affiliation(s)
- Igor Vassilev
- Faculty of Engineering and Natural Sciences, Tampere University, Finland
| | | | - Marika Kokko
- Faculty of Engineering and Natural Sciences, Tampere University, Finland.
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2
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Manchon C, Muniesa-Merino F, Llorente M, Esteve-Núñez A. Microbial photoelectrosynthesis: Feeding purple phototrophic bacteria electricity to produce bacterial biomass. Microb Biotechnol 2023; 16:569-578. [PMID: 36537073 PMCID: PMC9948228 DOI: 10.1111/1751-7915.14190] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 11/14/2022] [Accepted: 11/21/2022] [Indexed: 02/24/2023] Open
Abstract
Purple phototrophic bacteria are one of the main actors in chemolithotrophic carbon fixation and, therefore, fundamental in the biogeochemical cycle. These microbes are capable of using insoluble electron donors such as ferrous minerals or even carbon-based electrodes. Carbon fixation through extracellular electron uptake places purple phototrophic bacteria in the field of microbial electrosynthesis as key carbon capturing microorganisms. In this work we demonstrate biomass production dominated by purple phototrophic bacteria with a cathode (-0.6 V vs. Ag/AgCl) as electron donor. In addition, we compared the growth and microbial population structure with ferrous iron as the electron donor. We detect interaction between the cathode and the consortium showing a midpoint potential of 0.05 V (vs. Ag/AgCl). Microbial community analyses revealed different microbial communities depending on the electron donor, indicating different metabolic interactions. Electrochemical measurements together with population analyses point to Rhodopseudomonas genus as the key genus in the extracellular electron uptake. Furthermore, the genera Azospira and Azospirillum could play a role in the photoelectrotrophic consortium.
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Affiliation(s)
- Carlos Manchon
- Universidad de Alcalá, Madrid, Spain.,Nanoelectra, Madrid, Spain
| | | | | | - Abraham Esteve-Núñez
- Universidad de Alcalá, Madrid, Spain.,Nanoelectra, Madrid, Spain.,IMDEA Water, Alcalá de Henares, Spain
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Scholz F. Benefits of electrochemistry studies for the majority of students who will not become electrochemists. J Solid State Electrochem 2023. [DOI: 10.1007/s10008-023-05415-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
AbstractIn teaching electrochemistry, it is of primary importance to make students always aware of the relations between electrochemistry and all the non-electrochemical topics, which are taught. The vast majority of students will not specialise in electrochemistry, but they all can very much benefit from the basics and concepts of electrochemistry. This paper is aimed to give suggestions how the teaching of electrochemistry can easily be interrelated to topics of inorganic, organic, analytical, environmental chemistry, biochemistry and biotechnology.
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Korth B, Pous N, Hönig R, Haus P, Corrêa FB, Nunes da Rocha U, Puig S, Harnisch F. Electrochemical and Microbial Dissection of Electrified Biotrickling Filters. Front Microbiol 2022; 13:869474. [PMID: 35711746 PMCID: PMC9197458 DOI: 10.3389/fmicb.2022.869474] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 04/07/2022] [Indexed: 11/13/2022] Open
Abstract
Electrified biotrickling filters represent sustainable microbial electrochemical technology for treating organic carbon-deficient ammonium-contaminated waters. However, information on the microbiome of the conductive granule bed cathode remains inexistent. For uncovering this black box and for identifying key process parameters, minimally invasive sampling units were introduced, allowing for the extraction of granules from different reactor layers during reactor operation. Sampled granules were analyzed using cyclic voltammetry and molecular biological tools. Two main redox sites [-288 ± 18 mV and -206 ± 21 mV vs. standard hydrogen electrode (SHE)] related to bioelectrochemical denitrification were identified, exhibiting high activity in a broad pH range (pH 6-10). A genome-centric analysis revealed a complex nitrogen food web and the presence of typical denitrifiers like Pseudomonas nitroreducens and Paracoccus versutus with none of these species being identified as electroactive microorganism so far. These are the first results to provide insights into microbial structure-function relationships within electrified biotrickling filters and underline the robustness and application potential of bioelectrochemical denitrification for environmental remediation.
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Affiliation(s)
- Benjamin Korth
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - Narcís Pous
- Laboratory of Chemical and Environmental Engineering (LEQUiA), Institute of the Environment, University of Girona, Girona, Spain
| | - Richard Hönig
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - Philip Haus
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - Felipe Borim Corrêa
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - Ulisses Nunes da Rocha
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - Sebastià Puig
- Laboratory of Chemical and Environmental Engineering (LEQUiA), Institute of the Environment, University of Girona, Girona, Spain
| | - Falk Harnisch
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research, Leipzig, Germany
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Dai S, Korth B, Schwab L, Aulenta F, Vogt C, Harnisch F. Deciphering the fate of sulfate in one- and two-chamber bioelectrochemical systems. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2022.139942] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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6
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Hoareau M, Erable B, Chapleur O, Midoux C, Bureau C, Goubet A, Bergel A. Oxygen-reducing bidirectional microbial electrodes designed in real domestic wastewater. BIORESOURCE TECHNOLOGY 2021; 326:124663. [PMID: 33529981 DOI: 10.1016/j.biortech.2021.124663] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 12/31/2020] [Accepted: 12/31/2020] [Indexed: 06/12/2023]
Abstract
Microbial electrodes were designed in domestic wastewaters to catalyse the oxidation of organic matter (anode) and the reduction of oxygen (cathode) alternately. The successive aeration phases (cathode) enhanced the anodic efficiency, resulting in current densities of up to 6.4 Am-2 without the addition of any substrate. Using nitrogen during the anodic phases affected the microbial populations and the electrodes showed a lower ability to subsequently turn to O2 reduction than the microbial anodes formed in open-to-air conditions did. No strong difference was observed between internal and external biofilm, both of which showed a very large variety of taxa in terms of abundance as well as variance. They comprised a mix of aerobic and anaerobic species, many of which have already been identified separately in bioelectrochemical systems. Such a large diversity, which had not been observed in aerobic bidirectional bioelectrodes so far, can explain the efficiency and robustness observed here.
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Affiliation(s)
- Morgane Hoareau
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INP, UPS, Toulouse, France
| | - Benjamin Erable
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INP, UPS, Toulouse, France
| | - Olivier Chapleur
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, 92761 Antony, France
| | - Cédric Midoux
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, 92761 Antony, France
| | - Chrystelle Bureau
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, 92761 Antony, France
| | - Anne Goubet
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, 92761 Antony, France
| | - Alain Bergel
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INP, UPS, Toulouse, France.
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Vassilev I, Averesch NJH, Ledezma P, Kokko M. Anodic electro-fermentation: Empowering anaerobic production processes via anodic respiration. Biotechnol Adv 2021; 48:107728. [PMID: 33705913 DOI: 10.1016/j.biotechadv.2021.107728] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 01/31/2021] [Accepted: 03/03/2021] [Indexed: 11/24/2022]
Abstract
In nature as well as in industrial microbiology, all microorganisms need to achieve redox balance. Their redox state and energy conservation highly depend on the availability of a terminal electron acceptor, for example oxygen in aerobic production processes. Under anaerobic conditions in the absence of an electron acceptor, redox balance is achieved via the production of reduced carbon-compounds (fermentation). An alternative strategy to artificially stabilize microbial redox and energy state is the use of anodic electro-fermentation (AEF). This emerging biotechnology empowers respiration under anaerobic conditions using the anode of a bioelectrochemical system as an undepletable terminal electron acceptor. Electrochemical control of redox metabolism and energy conservation via AEF can steer the carbon metabolism towards a product of interest and avoid the need for continuous and cost-inefficient supply of oxygen as well as the production of mixed reduced by-products, as is the case in aerobic production and fermentation processes, respectively. The great challenge for AEF is to establish efficient extracellular electron transfer (EET) from the microbe to the anode and link it to central carbon metabolism to enhance the synthesis of a target product. This article reviews the advantages and challenges of AEF, EET mechanisms, microbial energy gain, and discusses the rational choice of substrate-product couple as well as the choice of microbial catalyst. Besides, it discusses the potential of the industrial model-organism Bacillus subtilis as a promising candidate for AEF, which has not been yet considered for such an application. This prospective review contributes to a better understanding of how industrial microbiology can benefit from AEF and analyses key-factors required to successfully implement AEF processes. Overall, this work aims to advance the young research field especially by critically revisiting the fundamental aspects of AEF.
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Affiliation(s)
- Igor Vassilev
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland.
| | - Nils J H Averesch
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, United States.
| | - Pablo Ledezma
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD, Australia.
| | - Marika Kokko
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland.
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Quejigo JR, Korth B, Kuchenbuch A, Harnisch F. Redox Potential Heterogeneity in Fixed-Bed Electrodes Leads to Microbial Stratification and Inhomogeneous Performance. CHEMSUSCHEM 2021; 14:1155-1165. [PMID: 33387375 PMCID: PMC7986606 DOI: 10.1002/cssc.202002611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/28/2020] [Indexed: 06/12/2023]
Abstract
Bed electrodes provide high electrode area-to-volume ratios represent a promising configuration for transferring bioelectrochemical systems close to industrial applications. Nevertheless, the intrinsic electrical resistance leads to poor polarization behavior. Therefore, the distribution of Geobacter spp. and their electrochemical performance within exemplary fixed-bed electrodes are investigated. A minimally invasive sampling system allows characterization of granules from different spatial locations of bed electrodes. Cyclic voltammetry of single granules (n=63) demonstrates that the major share of electroactivity (134.3 mA L-1 ) is achieved by approximately 10 % of the bed volume, specifically that being close to the current collector. Nevertheless, analysis of the microbial community reveals that Geobacter spp. dominated all sampled granules. These findings clearly demonstrate the need for engineered bed electrodes to improve electron exchange between microorganisms and granules.
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Affiliation(s)
- Jose Rodrigo Quejigo
- Department of Environmental MicrobiologyHelmholtz Centre for Environmental Research GmbH – UFZPermoser Str. 1504318LeipzigGermany
| | - Benjamin Korth
- Department of Environmental MicrobiologyHelmholtz Centre for Environmental Research GmbH – UFZPermoser Str. 1504318LeipzigGermany
| | - Anne Kuchenbuch
- Department of Environmental MicrobiologyHelmholtz Centre for Environmental Research GmbH – UFZPermoser Str. 1504318LeipzigGermany
| | - Falk Harnisch
- Department of Environmental MicrobiologyHelmholtz Centre for Environmental Research GmbH – UFZPermoser Str. 1504318LeipzigGermany
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