This work was supported by the BOF grant for SG from Ghent University. AL is supported by the Rutgers University NSF Fuels-IGERT. SA is supported by the European Union Framework Programme 7 project &#8220;ProEthanol 2G.&#8221; SA and KR are supported by Ghent University Multidisciplinary Research Partnership (MRP)&#8212;Biotechnology for a sustainable economy (01 MRA 510W). JD is supported by an IOF Advanced grant (F2012/IOF-Advanced/094). KR is supported by by the ERC Starter Grant &#8220;Electrotalk&#8221;. The authors thank Tim Lacoere for designing the TOC art figure, Robin Declerck for building the strip and absorption columns and Kun Guo for providing the inoculum source.

<ol>
	<li>Verstraete, W., Van de Caveye, P., Diamantis, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maximum+use+of+resources+present+in+domestic+&#34;used+water&#34;.">Maximum use of resources present in domestic &#34;used water&#34;.</a> Bioresource Technology. 100 (23), 5537-5545 (2009).</li><li>Lei, X., Sugiura, N., Feng, C., Maekawa, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pretreatment+of+anaerobic+digestion+effluent+with+ammonia+stripping+and+biogas+purification.">Pretreatment of anaerobic digestion effluent with ammonia stripping and biogas purification.</a> Journal of Hazardous Materials. 145 (3), 391-397 (2007).</li><li>Siegrist, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nitrogen+removal+from+digester+supernatant-comparison+of+chemical+and+biological+methods.">Nitrogen removal from digester supernatant-comparison of chemical and biological methods.</a> Water Science and Technology. 34 (1), 399-406 (1996).</li><li>Desloover, J., Abate Woldeyohannis, A., Verstraete, W., Boon, N., Rabaey, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrochemical+Resource+Recovery+from+Digestate+to+Prevent+Ammonia+Toxicity+during+Anaerobic+Digestion.">Electrochemical Resource Recovery from Digestate to Prevent Ammonia Toxicity during Anaerobic Digestion.</a> Environmental Science &amp; Technology. 46 (21), 12209-12216 (2012).</li><li>Kim, J. R., Zuo, Y., Regan, J. M., Logan, B. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+ammonia+loss+mechanisms+in+microbial+fuel+cells+treating+animal+wastewater.">Analysis of ammonia loss mechanisms in microbial fuel cells treating animal wastewater.</a> Biotechnology and Bioengineering. 99 (5), 1120-1127 (2008).</li><li>Emerson, K., Russo, R. C., Lund, R. E., Thurston, R. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aqueous+ammonia+equilibrium+calculations:+effect+of+pH+and+temperature.">Aqueous ammonia equilibrium calculations: effect of pH and temperature.</a> Journal of the Fisheries Board of Canada. 32 (12), 2379-2383 (1975).</li><li>Kuntke, P., Sleutels, T. H. J. A., Saakes, M., Buisman, C. J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogen+production+and+ammonium+recovery+from+urine+by+a+Microbial+Electrolysis+Cell.">Hydrogen production and ammonium recovery from urine by a Microbial Electrolysis Cell.</a> International Journal of Hydrogen Energy. 39 (10), 4771-4778 (2014).</li><li>Guo, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surfactant+treatment+of+carbon+felt+enhances+anodic+microbial+electrocatalysis+in+bioelectrochemical+systems.">Surfactant treatment of carbon felt enhances anodic microbial electrocatalysis in bioelectrochemical systems.</a> Electrochemistry Communications. 39, 1-4 (2014).</li><li>Guo, K., Chen, X., Freguia, S., Donose, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spontaneous+modification+of+carbon+surface+with+neutral+red+from+its+diazonium+salts+for+bioelectrochemical+systems.">Spontaneous modification of carbon surface with neutral red from its diazonium salts for bioelectrochemical systems.</a> Biosensors and Bioelectronics. 47, 184-189 (2013).</li><li>Rice, E. W., Greenberg, A. E., Clesceri, L. S., Eaton, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Standard Methods For The Examination Of Water And Wastewater. , (1992).</li><li>Andersen, S. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrolytic+Membrane+Extraction+Enables+Production+of+Fine+Chemicals+from+Biorefinery+Sidestreams.">Electrolytic Membrane Extraction Enables Production of Fine Chemicals from Biorefinery Sidestreams.</a> Environmental Science &amp; Technology. 48 (12), 7135-7142 (2014).</li><li>Harnisch, F., Rabaey, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Diversity+of+Techniques+to+Study+Electrochemically+Active+Biofilms+Highlights+the+Need+for+Standardization.">The Diversity of Techniques to Study Electrochemically Active Biofilms Highlights the Need for Standardization.</a> Chemsuschem. 5 (6), 1027-1038 (2012).</li><li>Clauwaert, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimizing+losses+in+bio-electrochemical+systems:+the+road+to+applications.">Minimizing losses in bio-electrochemical systems: the road to applications.</a> Applied Microbiology and Biotechnology. 79 (6), 901-913 (2008).</li><li>Atkins, P., De Paula, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Elements of Physical Chemistry. , (2012).</li><li>Aelterman, P., Freguia, S., Keller, J., Verstraete, W., Rabaey, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+anode+potential+regulates+bacterial+activity+in+microbial+fuel+cells.">The anode potential regulates bacterial activity in microbial fuel cells.</a> Applied Microbiology and Biotechnology. 78 (3), 409-418 (2008).</li><li>Kuntke, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ammonium+recovery+and+energy+production+from+urine+by+a+microbial+fuel+cell.">Ammonium recovery and energy production from urine by a microbial fuel cell.</a> Water Research. 46 (8), 2627-2636 (2012).</li><li>Liu, H., Cheng, S., Logan, B. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Power+Generation+in+Fed-Batch+Microbial+Fuel+Cells+as+a+Function+of+Ionic+Strength.">Power Generation in Fed-Batch Microbial Fuel Cells as a Function of Ionic Strength.</a> Temperature, and Reactor Configuration. Environmental Science &amp; Technology. 39 (14), 5488-5493 (2005).</li><li>Gimkiewicz, C., Harnisch, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Waste+Water+Derived+Electroactive+Microbial+Biofilms:+Growth,+Maintenance,+and+Basic+Characterization.">Waste Water Derived Electroactive Microbial Biofilms: Growth, Maintenance, and Basic Characterization.</a> JoVE. (82), e50800 (2013).</li><li>Ping, Q., Cohen, B., Dosoretz, C., He, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+investigation+of+fouling+of+cation+and+anion+exchange+membranes+in+microbial+desalination+cells.">Long-term investigation of fouling of cation and anion exchange membranes in microbial desalination cells.</a> Desalination. 325, 48-55 (2013).</li><li>Guerin, T., Mondido, M., McClenn, B., Peasley, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+resazurin+for+estimating+abundance+of+contaminant-degrading+micro-organisms.">Application of resazurin for estimating abundance of contaminant-degrading micro-organisms.</a> Letters in Applied Microbiology. 32 (5), 340-345 (2001).</li></ol>

The authors have nothing to disclose.

Este manuscrito fornece as ferramentas necessárias para criar uma bioelectrochemical e uma célula eletroquímica para a recuperação de amónio. Os cálculos apresentados na seção de resultados fornecem os parâmetros para a avaliação do desempenho do sistema. Os sistemas biológicos e eletroquímicas são semelhantes na configuração e função. A principal diferença entre os dois sistemas, é a escolha de uma corrente fixa para a célula electroquímica contra uma potencial ânodo fixo para a configuração b...

Recuperação de produtos valiosos de águas residuais ganha importância como valiosos recursos se tornam escassos e tratamento sem recuperação representa apenas um custo. Wastewater contém energia e nutrientes que podem ser recuperados, e recuperação de nutrientes pode ajudar a fechar o ciclo de produção 1. A recuperação de energia através de digestão anaeróbia é um processo bem estabelecido, enquanto a recuperação de nutrientes é menos comum. Recuperação de nutrientes dos fluxos de resíduos líquidos como a urina e estrume de animais tem sido amplamente investigada, por exemplo, através da produção de struvite e remoção direta de amônia 2,3. No entanto, a necessidade de adição de produtos químicos é uma desvantagem destes processos 4. Aqui apresentamos uma técnica para a recuperação de nutrientes catiônicos de fluxos de resíduos, incluindo potássio e amônio. A forma catiónica desses nutrientes permite a recuperação usando uma membrana selectiva de iões de um sistema electroquímico. Neste caso, o electrochemical sistema consiste de uma câmara de ânodo (onde tem lugar a oxidação), uma câmara de cátodo (em que a redução tem lugar) e uma membrana selectiva de iões para separar os compartimentos. A tensão é aplicada através da célula para produzir um fluxo de corrente do ânodo para o cátodo. Esta tensão pode ser gerado por uma fonte externa de energia para conduzir a oxidação da água e as reacções de redução. Em alternativa, a oxidação anódica, por exemplo, de produtos orgânicos, pode ser catalisada por bactérias electroactivos, que requerem menos energia. Para fechar o circuito e manter o equilíbrio de carga, uma espécie carregada deve migrar entre os eletrodos para cada elétron gerado. Transporte de amônio da câmara de anodo para o catodo câmara através de uma membrana de troca de cátions (CEM) podem, assim, compensar o fluxo de elétrons 4,5. A técnica apresentada aqui não só remove amónio de fluxos de resíduos, mas também permite a sua recuperação. Amoníaco Azoto total (TAN) existe em equilíbrio de ambos amónium (NH 4 +) e amoníaco (NH3), e é dependente do pH e da temperatura 6. NH 4 + é abundantemente disponíveis, devido à alta concentração TAN e próximo pH neutro na câmara do ânodo e a espécie com carga positiva pode, por conseguinte, ser conduzido pela corrente através do CEM para a câmara de cátodo. A corrente acciona a redução da água no cátodo, que leva à produção de iões hidróxido e gás hidrogénio. O equilíbrio TAN desloca-se para cerca de 100% de NH 3, devido ao elevado pH na câmara do cátodo (&gt; 10,0). NH 3 é um gás que pode ser facilmente transferida através de circulação de ar a partir da unidade de separação para a coluna de absorção onde é preso e concentrou-se em uma solução de ácido. Esta tecnologia tem o potencial para reduzir a toxicidade de amónio durante a digestão anaeróbica de fluxos rico-N como estrume, aumentando assim a recuperação de energia a partir destas correntes de resíduos, enquanto simultaneamentenutrientes que recuperam 4. Extração eletroquímica e bioelectrochemical de amônio também pode ser aplicado como técnica de recuperação de nutrientes sobre fluxos de resíduos com alto teor de TAN, como urina, evitando assim os custos para a remoção de nutrientes em uma ETAR 7. O protocolo aqui apresentado pode servir como uma base para muitas experiências electroquímicas e bioelectrochemical diferentes, como usamos um reactor modular. Diferentes tipos de eléctrodos, as membranas e espessuras de quadros podem ser combinados, tal como explicado no protocolo abaixo. O objectivo principal do protocolo é o de proporcionar um meio para a comparação de recuperação electroquímica de amónio e de amónio recuperação electroquímica bio-se utilizando uma célula de electrólise. Os sistemas são avaliadas em termos de eficiência de extracção, de entrada de alimentação e reprodutibilidade.

<table><tbody><tr><td>Carbon Felt 3.18 mm Thick</td><td>Alfa Aesar</td><td>ALFA43199</td><td>Used as bioanode, 110&amp;nbsp;mm x 110&amp;nbsp;mm</td></tr><tr><td>Ti electrode coated with Ir MMO&amp;nbsp;</td><td>Magneto Special Anodes (The Netherlands)</td><td></td><td>Used as stable anode for electrochemical tests</td></tr><tr><td>Stainless steel mesh</td><td>Solana (Belgium)</td><td>RVS 554/64: material AISI 316L, mesh width: 564 micron, wire thickness: 140 micron, mesh number: 36,6</td><td>Used as cathode, 110&amp;nbsp;mm x 110&amp;nbsp;mm</td></tr><tr><td>Stainless steel plate</td><td>Solana (Belgium)</td><td>inox 304 sheet, thickness: 0.5 mm</td><td>Used as current collector for the bioanode</td></tr><tr><td>Ag/AgCl Reference Electrode</td><td>Bio-Logic (France)</td><td>A-012167 RE-1B</td><td></td></tr><tr><td>Potentiostat (VSP Multipotentiostat)&amp;nbsp;</td><td>Bio-Logic (France)</td><td></td><td></td></tr><tr><td>EC Lab</td><td>Bio-Logic (France)</td><td></td><td>software for performing electrochemistry measurements</td></tr><tr><td>Cation Exchange Membrane</td><td>Membranes International (USA)</td><td>Ultrex CMI-7000</td><td>Pretreated according to the manufacturers&#039; instructions</td></tr><tr><td>Turbulence Promotor mesh</td><td>ElectroCell Europe A/S (Tarm, Denmark)</td><td>EPC20432-PP-2</td><td>spacer material, 110 mm x 110 mm</td></tr><tr><td>Connectors</td><td>Serto</td><td>1,281,161,120</td><td>Other sizes possible, dependant on tubing type and size of holes in frames</td></tr><tr><td>Strip and absorption column</td><td></td><td></td><td>In house design</td></tr><tr><td>Tubing</td><td>Masterflex</td><td>HV-06404-16</td><td></td></tr><tr><td>Gas bag</td><td>Keika Ventures</td><td></td><td>Kynar gas bag with Roberts valve</td></tr><tr><td>Rashig Rings</td><td>Glasatelier Saillart (Belgium)</td><td>Raschig rings 4 x 4 mm</td><td>Put inside the strip and absorption column to improve the air/liquid contact. Available with many suppliers</td></tr><tr><td>Rubber sheet</td><td></td><td></td><td>Cut to fit on the perspex frames</td></tr><tr><td>Perspex reactor frames</td><td>Vlaeminck, Beernem</td><td></td><td>In-house design, see tab &quot;reactor frames&quot; in this file</td></tr></tbody></table>

electrochemically and bioelectrochemically induced ammonium recovery

Streams such as urine and manure can contain high levels of ammonium, which could be recovered for reuse in agriculture or chemistry. The extraction of ammonium from an ammonium-rich stream is demonstrated using an electrochemical and a bioelectrochemical system. Both systems are controlled by a potentiostat to either fix the current (for the electrochemical cell) or fix the potential of the working electrode (for the bioelectrochemical cell). In the bioelectrochemical cell, electroactive bacteria catalyze the anodic reaction, whereas in the electrochemical cell the potentiostat applies a higher voltage to produce a current. The current and consequent restoration of the charge balance across the cell allow the transport of cations, such as ammonium, across a cation exchange membrane from the anolyte to the catholyte. The high pH of the catholyte leads to formation of ammonia, which can be stripped from the medium and captured in an acid solution, thus enabling the recovery of a valuable nutrient. The flux of ammonium across the membrane is characterized at different anolyte ammonium concentrations and currents for both the abiotic and biotic reactor systems. Both systems are compared based on current and removal efficiencies for ammonium, as well as the energy input required to drive ammonium transfer across the cation exchange membrane. Finally, a comparative analysis considering key aspects such as reliability, electrode cost, and rate is made.
This video article and protocol provide the necessary information to conduct electrochemical and bioelectrochemical ammonia recovery experiments. The reactor setup for the two cases is explained, as well as the reactor operation. We elaborate on data analysis for both reactor types and on the advantages and disadvantages of bioelectrochemical and electrochemical systems.

Cronoamperometria resulta do bioreactor Os resultados cronoamperometria, calculado de acordo com a Equação 1, mostra um gráfico típico para um reactor contínuo (Figura 4). No início da experiência, o ânodo e cátodo foram operados em modo de recirculação. Isto permite um biofilme para desenvolver e o início da produção corrente. Após 5 dias de operação, a densidade de corrente atinge um máximo, seguido de uma diminuição na produção corre...

Watch this Scientific Journal Video about Electrochemically and Bioelectrochemically Induced Ammonium Recovery at JoVE.com

Electrochemically and Bioelectrochemically Induced Ammonium Recovery

We demonstrate the extraction of ammonium from an ammonium-rich stream using an electrochemical and a bioelectrochemical system. The reactor setup, operation and data analysis are discussed.

Recuperação de Amónio Eletroquimicamente e Bioelectrochemically Induzida

Streams such as urine and manure can contain high levels of ammonium, which could be recovered for reuse in agriculture or chemistry. The extraction of ...

electrochemically-and-bioelectrochemically-induced-ammonium-recovery

Research

Education

JoVE Journal

JoVE Core

Chemistry

Chemical Equilibrium

SCIENTISTS IN ACTION

12.6K visualizações.  Ghent University. We demonstrate the extraction of ammonium from an ammonium-rich stream using an electrochemical and a bioelectrochemical system. The reactor setup, operation and data analysis are discussed. 

Vídeo: Electrochemically and Bioelectrochemically Induced Ammonium Recovery

Waste Water Derived Electroactive Microbial Biofilms: Growth, Maintenance, and Basic Characterization

The growth of anodic electroactive microbial biofilms from waste water inocula in a fed-batch reactor is demonstrated using a three-electrode setup controlled by a potentiostat. Thereby the use of potentiostats allows an exact adjustment of the electrode potential and ensures reproducible microbial culturing conditions. During growth the current production is monitored using chronoamperometry (CA). Based on these data the maximum current density (jmax) and the coulombic efficiency (CE) are discussed as measures for characterization of the bioelectrocatalytic performance. Cyclic voltammetry (CV), a nondestructive, i.e. noninvasive, method, is used to study the extracellular electron transfer (EET) of electroactive bacteria. CV measurements are performed on anodic biofilm electrodes in the presence of the microbial substrate, i.e. turnover conditions, and in the absence of the substrate, i.e. nonturnover conditions, using different scan rates. Subsequently, data analysis is exemplified and fundamental thermodynamic parameters of the microbial EET are derived and explained: peak potential (Ep), peak current density (jp), formal potential (Ef) and peak separation (&#916;Ep). Additionally the limits of the method and the state-of the art data analysis are addressed. Thereby this video-article shall provide a guide for the basic experimental steps and the fundamental data analysis.

Chronoamperometric growth of anodic electroactive microbial biofilms in a fed-batch reactor using a three-electrode setup, controlled by a potentiostat, is demonstrated. The extracellular electron transfer is characterized using cyclic voltammetry in the presence of the electron donor and in the absence of the electron donor. Fundamental data analysis is demonstrated.

The growth of anodic electroactive microbial biofilms from waste water inocula in a fed-batch reactor is demonstrated using a three-electrode setup ...

Ambiente

Electrochemical Detection of Deuterium Kinetic Isotope Effect on Extracellular Electron Transport in Shewanella oneidensis MR-1

Direct electrochemical detection of c-type cytochrome complexes embedded in the bacterial outer membrane (outer membrane c-type cytochrome complexes; OM c-Cyts) has recently emerged as a novel whole-cell analytical method to characterize the bacterial electron transport from the respiratory chain to the cell exterior, referred to as the extracellular electron transport (EET). While the pathway and kinetics of the electron flow during the EET reaction have been investigated, a whole-cell electrochemical method to examine the impact of cation transport associated with EET has not yet been established. In the present study, an example of a biochemical technique to examine the deuterium kinetic isotope effect (KIE) on EET through OM c-Cyts using a model microbe, Shewanella oneidensis MR-1, is described. The KIE on the EET process can be obtained if the EET through OM c-Cyts acts as the rate-limiting step in the microbial current production. To that end, before the addition of D2O, the supernatant solution was replaced with fresh media containing a sufficient amount of the electron donor to support the rate of upstream metabolic reactions, and to remove the planktonic cells from a uniform monolayer biofilm on the working electrode. Alternative methods to confirm the rate-limiting step in microbial current production as EET through OM c-Cyts are also described. Our technique of a whole-cell electrochemical assay for investigating proton transport kinetics can be applied to other electroactive microbial strains.

Electrochemical Detection of Deuterium Kinetic Isotope Effect on Extracellular Electron Transport in Shewanella oneidensis MR-1

Here we present a protocol of whole-cell electrochemical experiments to study the contribution of proton transport to the rate of extracellular electron transport via the outer-membrane cytochromes complex in Shewanella oneidensis MR-1.

Eletroquímico deteção de deutério cinética efeito isotópico no transporte de elétrons extracelular em Shewanella oneidensis MR-1

Direct electrochemical detection of c-type cytochrome complexes embedded in the bacterial outer membrane (outer membrane c-type cytochrome complexes; OM ...

Bioquímica

Ammonia Fiber Expansion (AFEX) Pretreatment of Lignocellulosic Biomass

Lignocellulosic materials are plant-derived feedstocks, such as crop residues (e.g., corn stover, rice straw, and sugar cane bagasse) and purpose-grown energy crops (e.g., miscanthus, and switchgrass) that are available in large quantities to produce biofuels, biochemicals, and animal feed. Plant polysaccharides (i.e., cellulose, hemicellulose, and pectin) embedded within cell walls are highly recalcitrant towards conversion into useful products. Ammonia fiber expansion (AFEX) is a thermochemical pretreatment that increases accessibility of polysaccharides to enzymes for hydrolysis into fermentable sugars. These released sugars can be converted into fuels and chemicals in a biorefinery. Here, we describe a laboratory-scale batch AFEX process to produce pretreated biomass on the gram-scale without any ammonia recycling. The laboratory-scale process can be used to identify optimal pretreatment conditions (e.g., ammonia loading, water loading, biomass loading, temperature, pressure, residence time, etc.) and generates sufficient quantities of pretreated samples for detailed physicochemical characterization and enzymatic/microbial analysis. The yield of fermentable sugars from enzymatic hydrolysis of corn stover pretreated using the laboratory-scale AFEX process is comparable to pilot-scale AFEX process under similar pretreatment conditions. This paper is intended to provide a detailed standard operating procedure for the safe and consistent operation of laboratory-scale reactors for performing AFEX pretreatment of lignocellulosic biomass.

Ammonia Fiber Expansion AFEX Pretreatment of Lignocellulosic Biomass

Ammonia fiber expansion (AFEX) is a thermochemical pretreatment technology that can convert lignocellulosic biomass (e.g., corn stover, rice straw, and sugarcane bagasse) into a highly digestible feedstock for both biofuels and animal feed applications. Here, we describe a laboratory-scale method for conducting AFEX pretreatment on lignocellulosic biomass.

Pré-tratamento de biomassa lignocelulósica da fibra de amônia (AFEX)

Lignocellulosic materials are plant-derived feedstocks, such as crop residues (e.g., corn stover, rice straw, and sugar cane bagasse) and purpose-grown ...

Self-standing Electrochemical Set-up to Enrich Anode-respiring Bacteria On-site

Anaerobic respiration coupled with electron transport to insoluble minerals (referred to as extracellular electron transport [EET]) is thought to be critical for microbial energy production and persistence in many subsurface environments, especially those lacking soluble terminal electron acceptors. While EET-capable microbes have been successfully isolated from various environments, the diversity of bacteria capable of EET is still poorly understood, especially in difficult-to-sample, low energy or extreme environments, such as many subsurface ecosystems. Here, we describe an on-site electrochemical system to enrich EET-capable bacteria using an anode as a respiratory terminal electron acceptor. This anode is connected&#160;to a cathode capable of&#160;catalyzing abiotic oxygen reduction. Comparing this approach with electrocultivation methods that use a potentiostat for poising the electrode potential, the two-electrode system does not require an external power source. We present an example of our on-site enrichment utilized in an alkaline pond at the Cedars, a terrestrial serpentinization site in Northern California. Prior attempts to cultivate mineral reducing bacteria were unsuccessful, which is likely due to the low-biomass nature of this site and/or the low relative abundance of metal reducing microbes. Prior to implementing our two-electrode enrichment, we measured the vertical profile of dissolved oxygen concentration. This allowed us to place the carbon felt anode and platinum-electroplated carbon felt cathode at depths that would support anaerobic and aerobic processes, respectively. Following on-site incubation, we further enriched the anodic electrode in the laboratory and confirmed&#160;a distinct microbial community compared to the surface-attached or biofilm communities normally observed at the Cedars. This enrichment subsequently led to the isolation of the first electrogenic microbe from the Cedars. This method of on-site microbial enrichment has the potential to greatly enhance the isolation of EET-capable bacteria from low biomass or difficult to sample habitats.

On-site microbial enrichment or in situ cultivation techniques can facilitate the isolation of difficult-to-culture microbial taxa, especially from low-biomass or geochemically extreme environments. Here, we describe an electrochemical set-up without using an external power source to enrich microbial strains that are capable of extracellular electron transport (EET).

Self-standing eletroquímica set-up para enriquecer o ânodo-proliferação de bactérias no local

Anaerobic respiration coupled with electron transport to insoluble minerals (referred to as extracellular electron transport [EET]) is thought to be ...

Characterizing Electron Transport through Living Biofilms

Here we demonstrate the method of electrochemical gating used to characterize electrical conductivity of electrode-grown microbial biofilms under physiologically relevant conditions.1 These measurements are performed on living biofilms in aqueous medium using source and drain electrodes patterned on a glass surface in a specialized configuration referred to as an interdigitated electrode (IDA) array. A biofilm is grown that extends across the gap connecting the source and drain. Potentials are applied to the electrodes (ES and ED) generating a source-drain current (ISD) through the biofilm between the electrodes. The dependency of electrical conductivity on gate potential (the average of the source and drain potentials, EG = [ED + ES]/2) is determined by systematically changing the gate potential and measuring the resulting source-drain current. The dependency of conductivity on gate potential provides mechanistic information about the extracellular electron transport process underlying the electrical conductivity of the specific biofilm under investigation. The electrochemical gating measurement method described here is based directly on that used by M. S. Wrighton2,3 and colleagues and R. W. Murray4,5,6 and colleagues in the 1980&#39;s to investigate thin film conductive polymers.

A protocol for measuring electrical conductivity of living microbial biofilms under physiologically relevant conditions is presented.

Caracterizando o transporte de elétrons através de biofilmes vivos

Here we demonstrate the method of electrochemical gating used to characterize electrical conductivity of electrode-grown microbial biofilms under ...

Química

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O

The importance of understanding the fate of nitrate (NO3&#8722;), which is the dominant N species transferred from terrestrial to aquatic ecosystems, has been increasing because global nitrogen loads have dramatically increased following industrialization. Dissimilatory nitrate reduction to ammonium (DNRA) and denitrification are both microbial processes that use NO3&#8722; for respiration. Compared to denitrification, quantitative determinations of the DNRA activity have been carried out only to a limited extent. This has led to an insufficient understanding of the importance of DNRA in NO3&#8722; transformations and the regulating factors of this process. The objective of this paper is to provide a detailed procedure for the measurement of the potential DNRA rate in environmental samples. In brief, the potential DNRA rate can be calculated from the 15N-labeled ammonium (15NH4+) accumulation rate in 15NO3&#8722; added incubation. The determination of the 14NH4+ and 15NH4+ concentrations described in this paper is comprised of the following steps. First, the NH4+ in the sample is extracted and trapped on an acidified glass filter as ammonium salt. Second, the trapped ammonium is eluted and oxidized to NO3&#8722; via persulfate oxidation. Third, the NO3&#8722; is converted to N2O via an N2O reductase deficient denitrifier. Finally, the converted N2O is analyzed using a previously developed quadrupole gas chromatography&#8211;mass spectrometry system. We applied this method to salt marsh sediments and calculated their potential DNRA rates, demonstrating that the proposed procedures allow a simple and more rapid determination compared to previously described methods.

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O

A series of methods to determine the potential DNRA rate based on 14NH4+/15NH4+ analyses is provided in detail. NH4+ is converted into N2O via several steps and analyzed using quadrupole gas chromatography&#8211;mass spectrometry.

Medição das Taxas Potenciais de Redução de Nitrato Dissimlatório para Amônio Com base em 14NH4+/15NH4+ Análises via Conversão Sequencial para N2O

The importance of understanding the fate of nitrate (NO3&#8722;), which is the dominant N species transferred from terrestrial to aquatic ecosystems, has ...

Asymmetric Thermoelectrochemical Cell for Harvesting Low-grade Heat under Isothermal Operation

Low-grade heat is abundantly available in the environment as waste heat. The efficient conversion of low-grade heat into electricity is very difficult. We developed an asymmetric thermoelectrochemical cell (aTEC) for heat-to-electricity conversion under isothermal operation in the charging and discharging processes without exploiting the thermal gradient or the thermal cycle. The aTEC is composed of a graphene oxide (GO) cathode, a polyaniline (PANI) anode, and 1M KCl as the electrolyte. The cell generates a voltage due to the pseudocapacitive reaction of GO when heating from room temperature (RT) to a high temperature (TH, ~40-90 &#176;C), and then current is successively produced by oxidizing PANI when an external electrical load is connected. The aTEC demonstrates a remarkable temperature coefficient of 4.1 mV/K and a high heat-to-electricity conversion efficiency of 3.32%, working at a TH = 70 &#176;C with a Carnot efficiency of 25.3%, unveiling a new promising thermoelectrochemical technology for low-grade heat recovery.

Low-grade heat is abundant, but its efficient recovery is still a great challenge. We report an asymmetric thermoelectrochemical cell using graphene oxide as a cathode and polyaniline as an anode with KCl as the electrolyte. This cell works under isothermal heating, exhibiting a high heat-to-electricity conversion efficiency in low-temperature regions.

Célula Termoeletroquímica assimétrica para colheita de calor de baixo grau operação isothermal

Low-grade heat is abundantly available in the environment as waste heat. The efficient conversion of low-grade heat into electricity is very difficult. We ...

Ion-Exchange Membranes for the Fabrication of Reverse Electrodialysis Device

Reverse electrodialysis (RED) is an effective way to generate power by mixing two different salt concentrations in water using cation-exchange membranes (CEM) and anion-exchange membranes (AEM). The RED stack is composed of an alternating arrangement of the cation-exchange membrane and anion-exchange membrane. The RED device acts as a potential candidate for fulfilling the universal demand for future energy crises. Here, in this article, we demonstrate a procedure to fabricate a reverse electrodialysis device using laboratory-scale CEM and AEM for power production. The active area of the ion-exchange membrane is 49 cm2. In this article, we provide a step-by-step procedure for synthesizing the membrane, followed by the stack&#39;s assembly and power measurement. The measurement conditions and net power output calculation have also been explained. Furthermore, we describe the fundamental parameters that are taken into consideration for obtaining a reliable outcome. We also provide a theoretical parameter that affects the overall cell performance relating to the membrane and the feed solution. In short, this experiment describes how to assemble and measure RED cells on the same platform. It also contains the working principle and calculation used for estimating the net power output of the RED stack using CEM and AEM membranes.

We demonstrate the fabrication of a reverse electrodialysis device using a cation-exchange membrane (CEM) and anion-exchange membrane (AEM) for power generation.

Membranas de troca de íons para a fabricação do dispositivo de eletrodiálise reversa

Reverse electrodialysis (RED) is an effective way to generate power by mixing two different salt concentrations in water using cation-exchange membranes ...

Engenharia

Ammonia Synthesis at Low Pressure

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in areas requiring ammonia for synthetic fertilizer. Such wind energy is often called &#34;stranded,&#34; because it is only available far from population centers where it can be directly used.
In the proposed low pressure process, nitrogen is made from air using pressure swing absorption, and hydrogen is produced by electrolysis of water. While these gases can react at approximately 400 &#176;C in the presence of a promoted conventional catalyst, the conversion is often limited by the reverse reaction, which makes this reaction only feasible at high pressures. This limitation can be removed by absorption on an ammine-like calcium or magnesium chloride. Such alkaline metal halides can effectively remove ammonia, thus suppressing the equilibrium constraints of the reaction. In the proposed absorption-enhanced ammonia synthesis process, the rate of reaction may then be controlled not by the chemical kinetics nor the absorption rates, but by the rate of the recycle of unreacted gases. The results compare favorably with ammonia made from a conventional small scale Haber-Bosch process.

Ammonia can be synthesized at low pressure by using a conventional catalyst and an ammonia selective absorbent.

Síntese de amônia a baixa pressão

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in ...

Bioengenharia

<meta charset="utf8"></head><body>Análise cronoamperométrica de EET em Lactiplantibacillus plantarum com DHNA

Characterizing Mediated Extracellular Electron Transfer in Lactic Acid Bacteria with a Three-Electrode, Two-Chamber Bioelectrochemical System

Many bacteria perform extracellular electron transfer (EET), whereby electrons are transferred from the cell to an extracellular terminal electron acceptor. This electron acceptor can be an electrode and electrons can be delivered indirectly via a redox-active mediator molecule. Here, we present a protocol to study mediated EET in Lactiplantibacillus plantarum, a probiotic lactic acid bacterium widely used in the food industry, using a bioelectrochemical system. We detail how to assemble a three-electrode, two-chambered bioelectrochemical system and provide guidance on characterizing EET in the presence of a soluble mediator using chronoamperometry and cyclic voltammetry techniques. We use representative data from 1,4-dihydroxy-2-naphthoic acid (DHNA)-mediated EET experiments with L. plantarum to demonstrate data analysis and interpretation. The techniques described in this protocol can open new opportunities for electro-fermentation and bioelectrocatalysis. Recent applications of this electrochemical technique with L. plantarum demonstrated an acceleration of metabolic flux towards producing fermentation end-products, which are critical flavor components in food fermentation. As such, this system has the potential to be further developed to alter flavors in food production or produce valuable chemicals.

<meta charset="utf8"></head><body>Caracterização da transferência de elétrons extracelular mediada em bactérias do ácido lático com um sistema bioeletroquímico de três eletrodos e duas câmaras

Here we present a protocol for characterizing mediated extracellular electron transfer (EET) in lactic acid bacteria using a three-electrode, two-chamber bioelectrochemical system. We illustrate this method with Lactiplantibacillus plantarum and the redox mediator 1,4-dihydroxy-2-naphthoic acid and provide a thorough description of the electrochemical techniques used to evaluate mediated EET.

Caracterização da transferência de elétrons extracelular mediada em bactérias do ácido lático com um sistema bioeletroquímico de três eletrodos e duas câmaras