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Rodríguez-Torres LM, Huerta-Miranda GA, Martínez-García AL, Mazón-Montijo DA, Hernández-Eligio A, Miranda-Hernández M, Juárez K. Influence of support materials on the electroactive behavior, structure and gene expression of wild type and GSU1771-deficient mutant of Geobacter sulfurreducens biofilms. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-33612-3. [PMID: 38758442 DOI: 10.1007/s11356-024-33612-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 05/05/2024] [Indexed: 05/18/2024]
Abstract
Geobacter sulfurreducens DL1 is a metal-reducing dissimilatory bacterium frequently used to produce electricity in bioelectrochemical systems (BES). The biofilm formed on electrodes is one of the most important factors for efficient electron transfer; this is possible due to the production of type IV pili and c-type cytochromes that allow it to carry out extracellular electron transfer (EET) to final acceptors. In this study, we analyzed the biofilm formed on different support materials (glass, hematite (Fe2O3) on glass, fluorine-doped tin oxide (FTO) semiconductor glass, Fe2O3 on FTO, graphite, and stainless steel) by G. sulfurreducens DL1 (WT) and GSU1771-deficient strain mutant (Δgsu1771). GSU1771 is a transcriptional regulator that controls the expression of several genes involved in electron transfer. Different approaches and experimental tests were carried out with the biofilms grown on the different support materials including structure analysis by confocal laser scanning microscopy (CLSM), characterization of electrochemical activity, and quantification of relative gene expression by RT-qPCR. The gene expression of selected genes involved in EET was analyzed, observing an overexpression of pgcA, omcS, omcM, and omcF from Δgsu1771 biofilms compared to those from WT, also the overexpression of the epsH gene, which is involved in exopolysaccharide synthesis. Although we observed that for the Δgsu1771 mutant strain, the associated redox processes are similar to the WT strain, and more current is produced, we think that this could be associated with a higher relative expression of certain genes involved in EET and in the production of exopolysaccharides despite the chemical environment where the biofilm develops. This study supports that G. sulfurreducens is capable of adapting to the electrochemical environment where it grows.
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Affiliation(s)
- Luis Miguel Rodríguez-Torres
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001. Col. Chamilpa, 62210, Cuernavaca, Morelos, México
| | - Guillermo Antonio Huerta-Miranda
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001. Col. Chamilpa, 62210, Cuernavaca, Morelos, México
| | - Ana Luisa Martínez-García
- Centro de Investigación en Materiales Avanzados S. C., Subsede Monterrey, Grupo de Investigación DORA-Lab, 66628, Apodaca, N. L, México
- Centro de Investigación e Innovación Tecnológica (CIIT), Grupo de Investigación DORA-Lab, Tecnológico Nacional de México Campus Nuevo León (TECNL), 66629, Apodaca, N. L, México
| | - Dalia Alejandra Mazón-Montijo
- Centro de Investigación en Materiales Avanzados S. C., Subsede Monterrey, Grupo de Investigación DORA-Lab, 66628, Apodaca, N. L, México
- Centro de Investigación e Innovación Tecnológica (CIIT), Grupo de Investigación DORA-Lab, Tecnológico Nacional de México Campus Nuevo León (TECNL), 66629, Apodaca, N. L, México
- Investigadores Por México, CONAHCYT, Ciudad de México, México
| | - Alberto Hernández-Eligio
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001. Col. Chamilpa, 62210, Cuernavaca, Morelos, México
- Investigadores Por México, CONAHCYT, Ciudad de México, México
| | - Margarita Miranda-Hernández
- Instituto de Energías Renovables, Universidad Nacional Autónoma de México, Priv. Xochicalco, 62580, Temixco, Morelos, México
| | - Katy Juárez
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001. Col. Chamilpa, 62210, Cuernavaca, Morelos, México.
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Dzofou Ngoumelah D, Heggeset TMB, Haugen T, Sulheim S, Wentzel A, Harnisch F, Kretzschmar J. Effect of model methanogens on the electrochemical activity, stability, and microbial community structure of Geobacter spp. dominated biofilm anodes. NPJ Biofilms Microbiomes 2024; 10:17. [PMID: 38443373 PMCID: PMC10915144 DOI: 10.1038/s41522-024-00490-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 02/20/2024] [Indexed: 03/07/2024] Open
Abstract
Combining anaerobic digestion (AD) and microbial electrochemical technologies (MET) in AD-MET holds great potential. Methanogens have been identified as one cause of decreased electrochemical activity and deterioration of Geobacter spp. biofilm anodes. A better understanding of the different interactions between methanogenic genera/species and Geobacter spp. biofilms is needed to shed light on the observed reduction in electrochemical activity and stability of Geobacter spp. dominated biofilms as well as observed changes in microbial communities of AD-MET. Here, we have analyzed electrochemical parameters and changes in the microbial community of Geobacter spp. biofilm anodes when exposed to three representative methanogens with different metabolic pathways, i.e., Methanosarcina barkeri, Methanobacterium formicicum, and Methanothrix soehngenii. M. barkeri negatively affected the performance and stability of Geobacter spp. biofilm anodes only in the initial batches. In contrast, M. formicicum did not affect the stability of Geobacter spp. biofilm anodes but caused a decrease in maximum current density of ~37%. M. soehngenii induced a coloration change of Geobacter spp. biofilm anodes and a decrease in the total transferred charge by ~40%. Characterization of biofilm samples after each experiment by 16S rRNA metabarcoding, whole metagenome nanopore sequencing, and shotgun sequencing showed a higher relative abundance of Geobacter spp. after exposure to M. barkeri as opposed to M. formicicum or M. soehngenii, despite the massive biofilm dispersal observed during initial exposure to M. barkeri.
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Affiliation(s)
- Daniel Dzofou Ngoumelah
- DBFZ Deutsches Biomasseforschungszentrum gemeinnützige GmbH (German Biomass Research Centre), Department of Biochemical Conversion, 04347, Leipzig, Germany
| | | | - Tone Haugen
- SINTEF Industry, Department of Biotechnology and Nanomedicine, 7034, Trondheim, Norway
| | - Snorre Sulheim
- SINTEF Industry, Department of Biotechnology and Nanomedicine, 7034, Trondheim, Norway
| | - Alexander Wentzel
- SINTEF Industry, Department of Biotechnology and Nanomedicine, 7034, Trondheim, Norway
| | - Falk Harnisch
- Helmholtz Centre for Environmental Research - UFZ, Department of Microbial Biotechnology, 04318, Leipzig, Germany
| | - Jörg Kretzschmar
- DBFZ Deutsches Biomasseforschungszentrum gemeinnützige GmbH (German Biomass Research Centre), Department of Biochemical Conversion, 04347, Leipzig, Germany.
- Zittau/Görlitz University of Applied Sciences, Faculty of Natural and Environmental Sciences, 02763, Zittau, Germany.
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Pereira J, Neves P, Nemanic V, Pereira MA, Sleutels T, Hamelers B, Heijne AT. Starvation combined with constant anode potential triggers intracellular electron storage in electro-active biofilms. WATER RESEARCH 2023; 242:120278. [PMID: 37413745 DOI: 10.1016/j.watres.2023.120278] [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: 04/05/2023] [Revised: 06/13/2023] [Accepted: 06/26/2023] [Indexed: 07/08/2023]
Abstract
The accumulation of electrons in the form of Extracellular Polymeric Substances (EPS) and poly-hydroxyalkanoates (PHA) has been studied in anaerobic processes by adjusting the access of microorganisms to the electron donor and final electron acceptor. In Bio-electrochemical systems (BESs), intermittent anode potential regimes have also recently been used to study electron storage in anodic electro-active biofilms (EABfs), but the effect of electron donor feeding mode on electron storage has not been explored. Therefore, in this study, the accumulation of electrons in the form of EPS and PHA was studied as a function of the operating conditions. EABfs were grown under both constant and intermittent anode potential regimes and fed with acetate (electron donor) continuously or in batch. Confocal Laser Scanning Microscopy (CLSM) and Fourier-Transform Infrared Spectroscopy (FTIR) were used to assess electron storage. The range of Coulombic efficiencies, from 25 to 82%, and the biomass yields, between 10 and 20%, indicate that storage could have been an alternative electron consuming process. From image processing, a 0.92 pixel ratio of poly-hydroxybutyrate (PHB) and amount of cells was found in the batch fed EABf grown under a constant anode potential. This storage was linked to the presence of living Geobacter and shows that energy gain and carbon source starvation were the triggers for intracellular electron storage. The highest EPS content (extracellular storage) was observed in the continuously fed EABf under an intermittent anode potential, showing that constant access to electron donor and intermittent access to the electron acceptor leads to the formation of EPS from the excess energy gained. Tailoring operating conditions can thus steer the microbial community and result in a trained EABf to perform a desired biological conversion, which can be beneficial for a more efficient and optimized BES.
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Affiliation(s)
- João Pereira
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, the Netherlands; Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700 AA, Wageningen, the Netherlands
| | - Patrícia Neves
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, the Netherlands; Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Vivian Nemanic
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, the Netherlands
| | - Maria Alcina Pereira
- Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; LABBELS -Associate Laboratory, Braga/Guimarães, Portugal
| | - Tom Sleutels
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, the Netherlands; Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, the Netherlands
| | - Bert Hamelers
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, the Netherlands; Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700 AA, Wageningen, the Netherlands
| | - Annemiek Ter Heijne
- Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700 AA, Wageningen, the Netherlands.
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Korth B, Pereira J, Sleutels T, Harnisch F, Heijne AT. Comparing theoretical and practical biomass yields calls for revisiting thermodynamic growth models for electroactive microorganisms. WATER RESEARCH 2023; 242:120279. [PMID: 37451189 DOI: 10.1016/j.watres.2023.120279] [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: 11/10/2022] [Revised: 06/12/2023] [Accepted: 06/26/2023] [Indexed: 07/18/2023]
Abstract
Research on electroactive microorganisms (EAM) often focuses either on their physiology and the underlying mechanisms of extracellular electron transfer or on their application in microbial electrochemical technologies (MET). Thermodynamic understanding of energy conversions related to growth and activity of EAM has received only a little attention. In this study, we aimed to prove the hypothesized restricted energy harvest of EAM by determining biomass yields by monitoring growth of acetate-fed biofilms presumably enriched in Geobacter, using optical coherence tomography, at three anode potentials and four acetate concentrations. Experiments were concurrently simulated using a refined thermodynamic model for EAM. Neither clear correlations were observed between biomass yield and anode potential nor acetate concentration, albeit the statistical significances are limited, mainly due to the observed experimental variances. The experimental biomass yield based on acetate consumption (YX/ac = 37 ± 9 mgCODbiomass gCODac-1) was higher than estimated by modeling, indicating limitations of existing growth models to predict yields of EAM. In contrast, the modeled biomass yield based on catabolic energy harvest was higher than the biomass yield from experimental data (YX/cat = 25.9 ± 6.8 mgCODbiomass kJ-1), supporting restricted energy harvest of EAM and indicating a role of not considered energy sinks. This calls for an adjusted growth model for EAM, including, e.g., the microbial electrochemical Peltier heat to improve the understanding and modeling of their energy metabolism. Furthermore, the reported biomass yields are important parameters to design strategies for influencing the interactions between EAM and other microorganisms and allowing more realistic feasibility assessments of MET.
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Affiliation(s)
- Benjamin Korth
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research GmbH - UFZ, Permoserstr. 15, Leipzig 04318, Germany.
| | - João Pereira
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9 8911, MA, Leeuwarden, The Netherlands; Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17 6700 AA, Wageningen, The Netherlands
| | - Tom Sleutels
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9 8911, MA, Leeuwarden, The Netherlands; Faculty of Science and Engineering, University of Groningen, Nijenborgh 4 9747 AG, Groningen, The Netherlands
| | - Falk Harnisch
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research GmbH - UFZ, Permoserstr. 15, Leipzig 04318, Germany
| | - Annemiek Ter Heijne
- Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17 6700 AA, Wageningen, The Netherlands
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5
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Chu N, Jiang Y, Liang Q, Liu P, Wang D, Chen X, Li D, Liang P, Zeng RJ, Zhang Y. Electricity-Driven Microbial Metabolism of Carbon and Nitrogen: A Waste-to-Resource Solution. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:4379-4395. [PMID: 36877891 DOI: 10.1021/acs.est.2c07588] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Electricity-driven microbial metabolism relies on the extracellular electron transfer (EET) process between microbes and electrodes and provides promise for resource recovery from wastewater and industrial discharges. Over the past decades, tremendous efforts have been dedicated to designing electrocatalysts and microbes, as well as hybrid systems to push this approach toward industrial adoption. This paper summarizes these advances in order to facilitate a better understanding of electricity-driven microbial metabolism as a sustainable waste-to-resource solution. Quantitative comparisons of microbial electrosynthesis and abiotic electrosynthesis are made, and the strategy of electrocatalyst-assisted microbial electrosynthesis is critically discussed. Nitrogen recovery processes including microbial electrochemical N2 fixation, electrocatalytic N2 reduction, dissimilatory nitrate reduction to ammonium (DNRA), and abiotic electrochemical nitrate reduction to ammonia (Abio-NRA) are systematically reviewed. Furthermore, the synchronous metabolism of carbon and nitrogen using hybrid inorganic-biological systems is discussed, including advanced physicochemical, microbial, and electrochemical characterizations involved in this field. Finally, perspectives for future trends are presented. The paper provides valuable insights on the potential contribution of electricity-driven microbial valorization of waste carbon and nitrogen toward a green and sustainable society.
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Affiliation(s)
- Na Chu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yong Jiang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Qinjun Liang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Panpan Liu
- School of Ecology and Environment, Zhengzhou University, Zhengzhou 450001, China
| | - Donglin Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xueming Chen
- Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China
| | - Daping Li
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
| | - Peng Liang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Raymond Jianxiong Zeng
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yifeng Zhang
- Department of Environmental Engineering, Technical University of Denmark, DK-2800 Lyngby, Denmark
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Winkelhorst M, Cabau-Peinado O, Straathof AJ, Jourdin L. Biomass-specific rates as key performance indicators: A nitrogen balancing method for biofilm-based electrochemical conversion. Front Bioeng Biotechnol 2023; 11:1096086. [PMID: 36741763 PMCID: PMC9892193 DOI: 10.3389/fbioe.2023.1096086] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/04/2023] [Indexed: 01/20/2023] Open
Abstract
Microbial electrochemical technologies (METs) employ microorganisms utilizing solid-state electrodes as either electron sink or electron source, such as in microbial electrosynthesis (MES). METs reaction rate is traditionally normalized to the electrode dimensions or to the electrolyte volume, but should also be normalized to biomass amount present in the system at any given time. In biofilm-based systems, a major challenge is to determine the biomass amount in a non-destructive manner, especially in systems operated in continuous mode and using 3D electrodes. We developed a simple method using a nitrogen balance and optical density to determine the amount of microorganisms in biofilm and in suspension at any given time. For four MES reactors converting CO2 to carboxylates, >99% of the biomass was present as biofilm after 69 days of reactor operation. After a lag phase, the biomass-specific growth rate had increased to 0.12-0.16 days-1. After 100 days of operation, growth became insignificant. Biomass-specific production rates of carboxylates varied between 0.08-0.37 molC molX -1d-1. Using biomass-specific rates, one can more effectively assess the performance of MES, identify its limitations, and compare it to other fermentation technologies.
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Maximum thickness of non-buffer limited electro-active biofilms decreases at higher anode potentials. Biofilm 2022; 4:100092. [DOI: 10.1016/j.bioflm.2022.100092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/13/2022] [Accepted: 11/06/2022] [Indexed: 11/13/2022] Open
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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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Pereira J, de Nooy S, Sleutels T, Ter Heijne A. Opportunities for visual techniques to determine characteristics and limitations of electro-active biofilms. Biotechnol Adv 2022; 60:108011. [PMID: 35753624 DOI: 10.1016/j.biotechadv.2022.108011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/10/2022] [Accepted: 06/18/2022] [Indexed: 11/02/2022]
Abstract
Optimization of bio-electrochemical systems (BESs) relies on a better understanding of electro-active biofilms (EABfs). These microbial communities are studied with a range of techniques, including electrochemical, visual and chemical techniques. Even though each of these techniques provides very valuable and wide-ranging information about EABfs, such as performance, morphology and biofilm composition, they are often destructive. Therefore, the information obtained from EABfs development and characterization studies are limited to a single characterization of EABfs and often limited to one time point that determines the end of the experiment. Despite being scarcer and not as commonly reported as destructive techniques, non-destructive visual techniques can be used to supplement EABfs characterization by adding in-situ information of EABfs functioning and its development throughout time. This opens the door to EABfs monitoring studies that can complement the information obtained with destructive techniques. In this review, we provide an overview of visual techniques and discuss the opportunities for combination with the established electrochemical techniques to study EABfs. By providing an overview of suitable visual techniques and discussing practical examples of combination of visual with electrochemical methods, this review aims at serving as a source of inspiration for future studies in the field of BESs.
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Affiliation(s)
- João Pereira
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, the Netherlands; Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands
| | - Sam de Nooy
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, the Netherlands; Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands
| | - Tom Sleutels
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, the Netherlands; Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG, Groningen, the Netherlands
| | - Annemiek Ter Heijne
- Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands.
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Häuser L, Erben J, Pillot G, Kerzenmacher S, Dreher W, Küstermann E. In vivo characterization of electroactive biofilms inside porous electrodes with MR Imaging. RSC Adv 2022; 12:17784-17793. [PMID: 35765339 PMCID: PMC9199086 DOI: 10.1039/d2ra01162j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 05/30/2022] [Indexed: 12/03/2022] Open
Abstract
Identifying the limiting processes of electroactive biofilms is key to improve the performance of bioelectrochemical systems (BES). For modelling and developing BES, spatial information of transport phenomena and biofilm distribution are required and can be determined by Magnetic Resonance Imaging (MRI) in vivo, in situ and in operando even inside opaque porous electrodes. A custom bioelectrochemical cell was designed that allows MRI measurements with a spatial resolution of 50 μm inside a 500 μm thick porous carbon electrode. The MRI data showed that only a fraction of the electrode pore space is colonized by the Shewanella oneidensis MR-1 biofilm. The maximum biofilm density was observed inside the porous electrode close to the electrode-medium interface. Inside the biofilm, mass transport by diffusion is lowered down to 45% compared to the bulk growth medium. The presented data and the methods can be used for detailed models of bioelectrochemical systems and for the design of improved electrode structures. The use of magnetic resonance imaging can contribute to a better understanding of limiting processes occurring in electroactive biofilms especially inside opaque porous electrodes.![]()
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Affiliation(s)
- Luca Häuser
- Center for Environmental Research and Sustainable Technology (UFT), University of Bremen 28359 Bremen Germany
| | | | - Guillaume Pillot
- Center for Environmental Research and Sustainable Technology (UFT), University of Bremen 28359 Bremen Germany
| | - Sven Kerzenmacher
- Center for Environmental Research and Sustainable Technology (UFT), University of Bremen 28359 Bremen Germany
| | - Wolfgang Dreher
- In-vivo-MR Group, Faculty 02 (Biology/Chemistry), University of Bremen 28359 Bremen Germany
| | - Ekkehard Küstermann
- In-vivo-MR Group, Faculty 02 (Biology/Chemistry), University of Bremen 28359 Bremen Germany
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Pereira J, Mediayati Y, van Veelen HPJ, Temmink H, Sleutels T, Hamelers B, Heijne AT. The effect of intermittent anode potential regimes on the morphology and extracellular matrix composition of electro-active bacteria. Biofilm 2022; 4:100064. [PMID: 34984335 PMCID: PMC8693015 DOI: 10.1016/j.bioflm.2021.100064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/01/2021] [Accepted: 12/08/2021] [Indexed: 11/25/2022] Open
Abstract
Electro-active bacteria (EAB) can form biofilms on an anode (so-called bioanodes), and use the electrode as electron acceptor for oxidation of organics in wastewater. So far, bioanodes have mainly been investigated under a continuous anode potential, but intermittent anode potential has resulted in higher currents and different biofilm morphologies. However, little is known about how intermittent potential influences the electron balance in the anode compartment. In this study, we investigated electron balances of bioanodes at intermittent anode potential regimes. We used a transparent non-capacitive electrode that also allowed for in-situ quantification of the EAB using optical coherence tomography (OCT). We observed comparable current densities between continuous and intermittent bioanodes, and stored charge was similar for all the applied intermittent times (5 mC). Electron balances were further investigated by quantifying Extracellular Polymeric Substances (EPS), by analyzing the elemental composition of biomass, and by quantifying biofilm and planktonic cells. For all tested conditions, a charge balance of the anode compartment showed that more electrons were diverted to planktonic cells than biofilm. Besides, 27–43% of the total charge was detected as soluble EPS in intermittent bioanodes, whereas only 15% was found as soluble EPS in continuous bioanodes. The amount of proteins in the EPS of biofilms was higher for intermittent operated bioanodes (0.21 mg COD proteins mg COD biofilm−1) than for continuous operated bioanodes (0.05 mg COD proteins mg COD biofilm−1). OCT revealed patchy morphologies for biofilms under intermittent anode potential. Overall, this study helped understanding that the use of a non-capacitive electrode and intermittent anode potential deviated electrons to other processes other than electric current at the electrode by identifying electron sinks in the anolyte and quantifying the accumulation of electrons in the form of EPS. Continuous acetate feeding and intermittent anode potential lead to EPS production in electro-active bacteria. A charge balance was made including soluble EPS and planktonic cells. Patchy biofilm morphologies and more planktonic cells were observed when intermittent anode potential was applied. Biofilms grown under intermittent anode potential had more EPS and more proteins.
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Affiliation(s)
- João Pereira
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands.,Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700, AA, Wageningen, the Netherlands
| | - Yuniki Mediayati
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands.,Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700, AA, Wageningen, the Netherlands
| | - H Pieter J van Veelen
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands
| | - Hardy Temmink
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands.,Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700, AA, Wageningen, the Netherlands
| | - Tom Sleutels
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands
| | - Bert Hamelers
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands.,Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700, AA, Wageningen, the Netherlands
| | - Annemiek Ter Heijne
- Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700, AA, Wageningen, the Netherlands
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12
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Scarabotti F, Rago L, Bühler K, Harnisch F. The electrode potential determines the yield coefficients of early-stage Geobacter sulfurreducens biofilm anodes. Bioelectrochemistry 2021; 140:107752. [PMID: 33618189 DOI: 10.1016/j.bioelechem.2021.107752] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/29/2021] [Accepted: 01/30/2021] [Indexed: 01/05/2023]
Abstract
Geobacter sulfurreducens is the model for electroactive microorganisms (EAM). EAM can use solid state terminal electron acceptors (TEA) including anodes via extracellular electron transfer (EET). Yield coefficients relate the produced cell number or biomass to the oxidized substrate or the reduced TEA. These data are not yet sufficiently available for EAM growing at anodes. Thus, this study provides information about kinetics as well as yield coefficients of early-stage G. sulfurreducens biofilms using anodes as TEA at the potentials of -200 mV, 0 mV and +200 mV (vs. Ag/AgCl sat. KCl). The selected microorganism was therefore cultivated in single and double chamber batch reactors on graphite or AuPd anodes. Interestingly, whereas the lag time and maximum current density within 12 days of growth differed, the anode potential does not influence the coulombic efficiency and the formal potential of the EET, which remains constant for all the experiments at ~ -300 to -350 mV. We demonstrated for the first time that the anode potential has a strong influence on single cell yield coefficients which ranged from 2.69 × 1012 cells mole--1 at -200 mV and 1.48 × 1012 cells mole--1 at 0 mV to 2.58 × 1011 cells mole--1 at +200 mV in single chamber reactors and from 1.15 × 1012 cells mole--1 at -200 mV to 8.98× 1011 cells mole--1 at 0 mV in double chamber reactors. This data can be useful for optimization and scaling-up of primary microbial electrochemical technologies.
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Affiliation(s)
- Francesco Scarabotti
- Department of Environmental Microbiology, Helmholtz-Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Laura Rago
- Department of Environmental Microbiology, Helmholtz-Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Katja Bühler
- Department Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Falk Harnisch
- Department of Environmental Microbiology, Helmholtz-Centre for Environmental Research - UFZ, Leipzig, Germany.
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13
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Pinck S, Ostormujof LM, Teychené S, Erable B. Microfluidic Microbial Bioelectrochemical Systems: An Integrated Investigation Platform for a More Fundamental Understanding of Electroactive Bacterial Biofilms. Microorganisms 2020; 8:E1841. [PMID: 33238493 PMCID: PMC7700166 DOI: 10.3390/microorganisms8111841] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 12/31/2022] Open
Abstract
It is the ambition of many researchers to finally be able to close in on the fundamental, coupled phenomena that occur during the formation and expression of electrocatalytic activity in electroactive biofilms. It is because of this desire to understand that bioelectrochemical systems (BESs) have been miniaturized into microBES by taking advantage of the worldwide development of microfluidics. Microfluidics tools applied to bioelectrochemistry permit even more fundamental studies of interactions and coupled phenomena occurring at the microscale, thanks, in particular, to the concomitant combination of electroanalysis, spectroscopic analytical techniques and real-time microscopy that is now possible. The analytical microsystem is therefore much better suited to the monitoring, not only of electroactive biofilm formation but also of the expression and disentangling of extracellular electron transfer (EET) catalytic mechanisms. This article reviews the details of the configurations of microfluidic BESs designed for selected objectives and their microfabrication techniques. Because the aim is to manipulate microvolumes and due to the high modularity of the experimental systems, the interfacial conditions between electrodes and electrolytes are perfectly controlled in terms of physicochemistry (pH, nutrients, chemical effectors, etc.) and hydrodynamics (shear, material transport, etc.). Most of the theoretical advances have been obtained thanks to work carried out using models of electroactive bacteria monocultures, mainly to simplify biological investigation systems. However, a huge virgin field of investigation still remains to be explored by taking advantage of the capacities of microfluidic BESs regarding the complexity and interactions of mixed electroactive biofilms.
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Affiliation(s)
| | | | | | - Benjamin Erable
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, 31432 Toulouse, France; (S.P.); (L.M.O.); (S.T.)
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14
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Guo Y, Rosa LF, Müller S, Harnisch F. Monitoring stratification of anode biofilms in bioelectrochemical laminar flow reactors using flow cytometry. ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY 2020; 4:100062. [PMID: 36157706 PMCID: PMC9488081 DOI: 10.1016/j.ese.2020.100062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/25/2020] [Accepted: 09/26/2020] [Indexed: 06/16/2023]
Abstract
A laminar flow bioelectrochemical systems (BES) was designed and benchmarked using microbial anodes dominated with Geobacter spp. The reactor architecture was based on modeled flow fields, the resulting structure was 3D printed and used for BES manufacturing. Stratification of the substrate availability within the reactor channels led to heterogeneous biomass distribution, with the maximum biomass found mainly in the initial/middle channels. The anode performance was assessed for different hydraulic retention times while coulombic efficiencies of up to 100% (including also hydrogen recycling from the cathode) and current densities of up to 75 μA cm-2 at an anode surface to volume ratio of 1770 cm2 L-1 after 35 days were achieved. This low current density can be clearly attributed to the heterogeneous distributions of biomass and the stratification of the microbial community structure. Further, it was shown that time and space resolved analysis of the reactor microbiomes per channel is feasible using flow cytometry.
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15
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Hou R, Luo C, Zhou S, Wang Y, Yuan Y, Zhou S. Anode potential-dependent protection of electroactive biofilms against metal ion shock via regulating extracellular polymeric substances. WATER RESEARCH 2020; 178:115845. [PMID: 32353609 DOI: 10.1016/j.watres.2020.115845] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 04/01/2020] [Accepted: 04/15/2020] [Indexed: 06/11/2023]
Abstract
Extracellular polymeric substances (EPS) have been considered as a barrier for toxic species penetration into the cells, but their function in protecting electroactive biofilms (EABs) had been rarely revealed. In this study, the anode potential was used to regulate the EPS quantity and components in mixed-culture EABs, where their resistance to Ag+ shock was assessed. The results showed that the EAB grown at 0 V showed the highest anti-shock capability by the Ag+ exposure compared to those grown at -0.2, 0.2, and 0.4 V. The EAB produced at 0 V had both of the highest amounts of loosely bound EPS (LB-EPS; 61.9 mg-EPS/g-VSS) and tightly bound EPS (TB-EPS; 74.8 mg-EPS/g-VSS) than those grown under other potentials, where proteins and humic acid were the predominated components. The abundance of genes associated with EPS biosynthesis were also confirmed to be related with the applied anode potentials, based on the metagenomic analysis. Considering proteins and humic acid in LB-EPS showed positive linearity with the current recovery and viability of the EABs, these two main components might play important roles in reducing the Ag+ toxicity. Synchronous fourier transform infrared (FTIR) spectroscopy integrated two-dimensional correlation spectroscopy (2D-COS) analyses further confirmed that the oxygen and nitrogen moieties (i.e. amide, carbonyl CO, phenolic, and C-O-C) in proteins and humic acid of the LB-EPS were response for the binding with the Ag+ to prevent the penetration into the cells. The underlying molecular mechanisms of EPS in protecting EABs from the Ag+ shock explored in this study can provide implications for developing new methods to construct highly stable EABs.
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Affiliation(s)
- Rui Hou
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China
| | - Cheng Luo
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China
| | - Shaofeng Zhou
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China
| | - Yi Wang
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China
| | - Yong Yuan
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China.
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, School of Resources and Environment, Fujian Agriculture and Forestry, Fuzhou, 350000, China
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16
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Koch C, Kuchenbuch A, Marosvölgyi M, Weisshart K, Harnisch F. Label‐Free Four‐Dimensional Visualization of Anaerobically Growing Electroactive Biofilms. Cytometry A 2020; 97:737-741. [DOI: 10.1002/cyto.a.24169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 05/29/2020] [Accepted: 06/02/2020] [Indexed: 01/27/2023]
Affiliation(s)
- Christin Koch
- Department of Environmental MicrobiologyHelmholtz Center for Environmental Research GmbH – UFZ Permoserstraße 15, Leipzig 04318 Germany
| | - Anne Kuchenbuch
- Department of Environmental MicrobiologyHelmholtz Center for Environmental Research GmbH – UFZ Permoserstraße 15, Leipzig 04318 Germany
| | | | - Klaus Weisshart
- Carl Zeiss Microscopy GmbH Carl‐Zeiss‐Promenade 10, Jena 07745 Germany
| | - Falk Harnisch
- Department of Environmental MicrobiologyHelmholtz Center for Environmental Research GmbH – UFZ Permoserstraße 15, Leipzig 04318 Germany
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17
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Korth B, Kretzschmar J, Bartz M, Kuchenbuch A, Harnisch F. Determining incremental coulombic efficiency and physiological parameters of early stage Geobacter spp. enrichment biofilms. PLoS One 2020; 15:e0234077. [PMID: 32559199 PMCID: PMC7304624 DOI: 10.1371/journal.pone.0234077] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 05/18/2020] [Indexed: 01/06/2023] Open
Abstract
Geobacter spp. enrichment biofilms were cultivated in batch using one-chamber and two-chamber bioelectrochemical reactors. Time-resolved substrate quantification was performed to derive physiological parameters as well as incremental coulombic efficiency (i.e., coulombic efficiency during one batch cycle, here every 6h) during early stage biofilm development. The results of one-chamber reactors revealed an intermediate acetate increase putatively due to the presence of acetogens. Total coulombic efficiencies of two-chamber reactors were considerable lower (19.6±8.3% and 49.3±13.2% for 1st and 2nd batch cycle, respectively) compared to usually reported values of mature Geobacter spp. enrichment biofilms presumably reflecting energetic requirements for biomass production (i.e., cells and extracellular polymeric substances) during early stages of biofilm development. The incremental coulombic efficiency exhibits considerable changes during batch cycles indicating shifts between phases of maximizing metabolic rates and maximizing biomass yield. Analysis based on Michaelis-Menten kinetics yielded maximum substrate uptake rates (vmax,Ac, vmax,I) and half-saturation concentration coefficients (KM,Ac,KM,I) based on acetate uptake or current production, respectively. The latter is usually reported in literature but neglects energy demands for biofilm growth and maintenance as well as acetate and electron storage. From 1st to 2nd batch cycle, vmax,Ac and KM,Ac, decreased from 0.0042-0.0051 mmol Ac- h-1 cm-2 to 0.0031-0.0037 mmol Ac- h-1 cm-2 and 1.02-2.61 mM Ac- to 0.28-0.42 mM Ac-, respectively. Furthermore, differences between KM,Ac/KM,I and vmax,Ac/vmax,I were observed providing insights into the physiology of Geobacter spp. enrichment biofilms. Notably, KM,I considerably scattered while vmax,Ac/vmax,I and KM,Ac remained rather stable indicating that acetate transport within biofilm only marginally affects reaction rates. The observed data variation mandates the requirement of a more detailed analysis with an improved experimental system, e.g., using flow conditions and a comparison with Geobacter spp. pure cultures.
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Affiliation(s)
- Benjamin Korth
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research—UFZ, Leipzig, Saxony, Germany
| | - Jörg Kretzschmar
- Biochemical Conversion Department, DBFZ Deutsches Biomasseforschungszentrum gemeinnützige GmbH, Leipzig, Saxony, Germany
| | - Manuel Bartz
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research—UFZ, Leipzig, Saxony, Germany
| | - Anne Kuchenbuch
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research—UFZ, Leipzig, Saxony, Germany
| | - Falk Harnisch
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research—UFZ, Leipzig, Saxony, Germany
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18
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Georg S, de Eguren Cordoba I, Sleutels T, Kuntke P, Heijne AT, Buisman CJN. Competition of electrogens with methanogens for hydrogen in bioanodes. WATER RESEARCH 2020; 170:115292. [PMID: 31778968 DOI: 10.1016/j.watres.2019.115292] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 11/05/2019] [Accepted: 11/06/2019] [Indexed: 06/10/2023]
Abstract
Bioelectrochemical systems (BES) can provide an energy efficient way to recover nutrients from wastewaters. However, the electron donors available in wastewater are often not sufficient to recover the total amount of nutrients. This work investigates hydrogen (H2) as an additional substrate for bioanodes. This hydrogen can be produced in the fermentation of complex organic waste or could be recycled from the cathode. Understanding how to influence the competition of electroactive microorganisms (EAM) with methanogens for H2 gas from different sources is key to successful application of H2 as additional electron donor in bioelectrochemical nutrient recovery. Ethanol (EtOH) was used as model compound for complex wastewaters since it is fermented into both acetate and H2. EtOH was efficiently converted into electricity (e-) by a syntrophic biofilm. Total recovered charge from 1 mM EtOH was 20% higher than for the same amount of acetate. This means that H2 from EtOH fermentation was converted by EAM into electricity. Low EtOH concentrations (1 mM) led to higher conversion efficiencies into electricity than higher concentrations (5 and 10 mM). Thermodynamic calculations show this correlates with a higher energy gain for electrogens compared to methanogens at low H2 concentrations. Cumulatively adding 1 mM EtOH without medium exchange (14 times in 14 days) resulted in stable conversion of H2 to e- (67%-77% e-) rather than methane. With H2 gas as electron donor, 68 ± 2% H2 was converted into e- with no carbon source added, and still 53 ± 5% to e- when 50 mM bicarbonate was provided. These results show that under the provided conditions, electrogens can outcompete methanogens for H2 as additional electron donor in MECs for nutrient recovery.
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Affiliation(s)
- S Georg
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands; Department of Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700 AA, Wageningen, the Netherlands.
| | - I de Eguren Cordoba
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands
| | - T Sleutels
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands
| | - P Kuntke
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands
| | - A Ter Heijne
- Department of Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700 AA, Wageningen, the Netherlands.
| | - C J N Buisman
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911MA, Leeuwarden, the Netherlands; Department of Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700 AA, Wageningen, the Netherlands
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19
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Caizán-Juanarena L, Krug JR, Vergeldt FJ, Kleijn JM, Velders AH, Van As H, Ter Heijne A. 3D biofilm visualization and quantification on granular bioanodes with magnetic resonance imaging. WATER RESEARCH 2019; 167:115059. [PMID: 31562986 DOI: 10.1016/j.watres.2019.115059] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 06/10/2023]
Abstract
The use of microbial fuel cells (MFCs) for wastewater treatment fits in a circular economy context, as they can produce electricity by the removal of organic matter in the wastewater. Activated carbon (AC) granules are an attractive electrode material for bioanodes in MFCs, as they are cheap and provide electroactive bacteria with a large surface area for attachment. The characterization of biofilm growth on AC granules, however, is challenging due to their high roughness and three-dimensional structure. In this research, we show that 3D magnetic resonance imaging (MRI) can be used to visualize biofilm distribution and determine its volume on irregular-shaped single AC granules in a non-destructive way, while being combined with electrochemical and biomass analyses. Ten AC granules with electroactive biofilm (i.e. granular bioanodes) were collected at different growth stages (3 to 21 days after microbial inoculation) from a multi-anode MFC and T1-weighted 3D-MRI experiments were performed for three-dimensional biofilm visualization. With time, a more homogeneous biofilm distribution and an increased biofilm thickness could be observed in the 3D-MRI images. Biofilm volumes varied from 0.4 μL (day 4) to 2 μL (day 21) and were linearly correlated (R2 = 0.9) to the total produced electric charge and total nitrogen content of the granular bioanodes, with values of 66.4 C μL-1 and 17 μg N μL-1, respectively. In future, in situ MRI measurements could be used to monitor biofilm growth and distribution on AC granules.
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Affiliation(s)
- Leire Caizán-Juanarena
- Environmental Technology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
| | - Julia R Krug
- Laboratory of BioNanoTechnology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands; Laboratory of Biophysics, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands; MAGNEtic resonance research FacilitY, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Frank J Vergeldt
- Laboratory of Biophysics, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands; MAGNEtic resonance research FacilitY, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - J Mieke Kleijn
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Aldrik H Velders
- Laboratory of BioNanoTechnology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands; MAGNEtic resonance research FacilitY, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Henk Van As
- Laboratory of Biophysics, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands; MAGNEtic resonance research FacilitY, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
| | - Annemiek Ter Heijne
- Environmental Technology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands.
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20
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Korth B, Harnisch F. Spotlight on the Energy Harvest of Electroactive Microorganisms: The Impact of the Applied Anode Potential. Front Microbiol 2019; 10:1352. [PMID: 31293531 PMCID: PMC6606774 DOI: 10.3389/fmicb.2019.01352] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 05/31/2019] [Indexed: 11/13/2022] Open
Abstract
Electroactive microorganisms (EAM) harvest energy by reducing insoluble terminal electron acceptors (TEA) including electrodes via extracellular electron transfer (EET). Therefore, compared to microorganisms respiring soluble TEA, an adapted approach is required for thermodynamic analyses. In EAM, the thermodynamic frame (i.e., maximum available energy) is restricted as only a share of the energy difference between electron donor and TEA is exploited via the electron-transport chain to generate proton-motive force being subsequently utilized for ATP synthesis. However, according to a common misconception, the anode potential is suggested to co-determine the thermodynamic frame of EAM. By comparing the model organism Geobacter spp. and microorganisms respiring soluble TEA, we reason that a considerable part of the electron-transport chain of EAM performing direct EET does not contribute to the build-up of proton-motive force and thus, the anode potential does not co-determine the thermodynamic frame. Furthermore, using a modeling platform demonstrates that the influence of anode potential on energy harvest is solely a kinetic effect. When facing low anode potentials, NADH is accumulating due to a slow direct EET rate leading to a restricted exploitation of the thermodynamic frame. For anode potentials ≥ 0.2 V (vs. SHE), EET kinetics, NAD+/NADH ratio as well as exploitation of the thermodynamic frame are maximized, and a further potential increase does not result in higher energy harvest. Considering the limited influence of the anode potential on energy harvest of EAM is a prerequisite to improve thermodynamic analyses, microbial resource mining, and to transfer microbial electrochemical technologies (MET) into practice.
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Affiliation(s)
- Benjamin Korth
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Falk Harnisch
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
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21
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Rosenthal AF, Griffin JS, Wagner M, Packman AI, Balogun O, Wells GF. Morphological analysis of pore size and connectivity in a thick mixed-culture biofilm. Biotechnol Bioeng 2018; 115:2268-2279. [PMID: 29777596 DOI: 10.1002/bit.26729] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 05/07/2018] [Accepted: 05/16/2018] [Indexed: 11/07/2022]
Abstract
Morphological parameters are commonly used to predict transport and metabolic kinetics in biofilms. Yet, quantification of biofilm morphology remains challenging because of imaging technology limitations and lack of robust analytical approaches. We present a novel set of imaging and image analysis techniques to estimate internal porosity, pore size distributions, and pore network connectivity to a depth of 1 mm at a resolution of 10 µm in a biofilm exhibiting both heterotrophic and nitrifying activities. Optical coherence tomography (OCT) scans revealed an extensive pore network with diameters as large as 110 µm directly connected to the biofilm surface and surrounding fluid. Thin-section fluorescence in situ hybridization microscopy revealed that ammonia-oxidizing bacteria (AOB) distributed through the entire thickness of the biofilm. AOB were particularly concentrated in the biofilm around internal pores. Areal porosity values estimated from OCT scans were consistently lower than those estimated from multiphoton laser scanning microscopy, though the two imaging modalities showed a statistically significant correlation (r = 0.49, p < 0.0001). Estimates of areal porosity were moderately sensitive to gray-level threshold selection, though several automated thresholding algorithms yielded similar values to those obtained by manually thresholding performed by a panel of environmental engineering researchers (±25% relative error). These findings advance our ability to quantitatively describe the geometry of biofilm internal pore networks at length scales relevant to engineered biofilm reactors and suggest that internal pore structures provide crucial habitat for nitrifier growth.
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Affiliation(s)
- Alex F Rosenthal
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois
| | - James S Griffin
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois
| | - Michael Wagner
- Department of Water Chemistry and Water Technology, Engler-Bunte-Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Aaron I Packman
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois
| | - Oluwaseyi Balogun
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois
| | - George F Wells
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois
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