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Wagner AO, Prem EM, Markt R, Kaufmann R, Illmer P. Formation of phenylacetic acid and phenylpropionic acid under different overload conditions during mesophilic and thermophilic anaerobic digestion. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:26. [PMID: 30787959 PMCID: PMC6368962 DOI: 10.1186/s13068-019-1370-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 02/03/2019] [Indexed: 05/08/2023]
Abstract
BACKGROUND Substrate spectra for anaerobic digestion have been broadened in the past decade, inter alia, due to the application of different pretreatment strategies and now include materials rich in lignocellulose, protein, and/or fat. The application of these substrates, however, also entails risks regarding the formation of undesired by-products, among which phenolic compounds are known to accumulate under unfavorable digestion conditions. METHODS Different states of overload were simulated in batch experiments while reviewing the generation of phenyl acids out of different lab-use substrates in order to evaluate the impact on biogas and methane production as well as some additional process performance parameters under defined laboratory conditions. Investigations were conducted under both mesophilic and thermophilic conditions. RESULTS It could be shown that the tested input materials led to the formation of phenyl acids in a substrate-dependent manner with the formation itself being less temperature driven. Once formed, the formation of phenyl acids turned out to be a reversible process. CONCLUSIONS Although a mandatory negative impact of phenyl acids per se on the anaerobic digestion process in general and the methanogenesis process in particular could not be proven, phenyl acids, however, seem to play an important role in the microbial response to overloaded biogas systems.
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Affiliation(s)
- Andreas Otto Wagner
- Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria
| | - Eva Maria Prem
- Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria
| | - Rudolf Markt
- Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria
| | - Rüdiger Kaufmann
- Department of Ecology, Universität Innsbruck, Sternwartestr. 15/Technikerstraße 25/5, 6020 Innsbruck, Austria
| | - Paul Illmer
- Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria
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Process Disturbances in Agricultural Biogas Production—Causes, Mechanisms and Effects on the Biogas Microbiome: A Review. ENERGIES 2019. [DOI: 10.3390/en12030365] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Disturbances of the anaerobic digestion process reduce the economic and environmental performance of biogas systems. A better understanding of the highly complex process is of crucial importance in order to avoid disturbances. This review defines process disturbances as significant changes in the functionality within the microbial community leading to unacceptable and severe decreases in biogas production and requiring an active counteraction to be overcome. The main types of process disturbances in agricultural biogas production are classified as unfavorable process temperatures, fluctuations in the availability of macro- and micronutrients (feedstock variability), overload of the microbial degradation potential, process-related accumulation of inhibiting metabolites such as hydrogen (H2), ammonium/ammonia (NH4+/NH3) or hydrogen sulphide (H2S) and inhibition by other organic and inorganic toxicants. Causes, mechanisms and effects on the biogas microbiome are discussed. The need for a knowledge-based microbiome management to ensure a stable and efficient production of biogas with low susceptibility to disturbances is derived and an outlook on potential future process monitoring and control by means of microbial indicators is provided.
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A Review on Nanoparticles as Boon for Biogas Producers—Nano Fuels and Biosensing Monitoring. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app9010059] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Nanotechnology has an increasingly large impact on a broad scope of biotechnological, pharmacological and pure technological applications. Its current use in bioenergy production from biomass is very restricted. The present study is based on the utilization of nanoparticles as an additive to feed bacteria that break down natural substances. The novel notion of dosing ions using modified nanoparticles can be used to progress up biogas production in oxygen free digestion processes. While minute nanoparticles are unstable, they can be designed to provide ions in a controlled approach, so that the maximum enhancement of biogas production that has been reported can be obtained. Nanoparticles are dissolved in a programmed way in an anaerobic atmosphere and are supplied in a sustainable manner to microbiotic organisms responsible for the degradation of organic material, which is a role that fits them well. Therefore, biogas fabrication can be increased up to 200%, thereby increasing the degradation of organic waste.
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Zhang C, Yuan Q, Lu Y. Inhibitory effects of ammonia on syntrophic propionate oxidation in anaerobic digester sludge. WATER RESEARCH 2018; 146:275-287. [PMID: 30278382 DOI: 10.1016/j.watres.2018.09.046] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/30/2018] [Accepted: 09/21/2018] [Indexed: 06/08/2023]
Abstract
Syntrophic propionate oxidation (SPO) coupled with methanogenesis is often inhibited under high ammonium concentrations in anaerobic digesters. However, the inhibitory mechanism remains poorly understood. We conducted two independent laboratory experiments with a swine manure digester sludge. In experiment I, RNA-based stable isotope probing (SIP) was applied to determine the active players of both bacteria and methanogens involved in SPO under different ammonium concentrations (0, 3 and 7 g NH4+N L-1). In experiment II, the dynamics of the bacterial community under ammonia stress was monitored using the 16S rRNA pyrosequencing and quantitative PCR under similar conditions as in experiment I but without the addition of external propionate. An additional higher ammonium treatment (10 g NH4+N L-1) was applied in experiment II to maximize the ammonia stress. We identified that the Smithella bacteria and the Methanosaetaceae and Methanospirillaceae archaea were the most active players involved in SPO and methanogenesis. We revealed that Smithella, Methanosaetaceae and Methanospirillaceae were moderately and severely inhibited at 3 and 7-10 g NH4+N L-1, respectively. However, the fermentative bacteria appeared to be more tolerant to ammonia stress. The microbial responses were corroborated with the accumulation of VFAs and the repression of methanogenesis under high ammonium conditions.
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Affiliation(s)
- Chen Zhang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China; College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Quan Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Yahai Lu
- College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
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Montag D, Schink B. Formate and Hydrogen as Electron Shuttles in Terminal Fermentations in an Oligotrophic Freshwater Lake Sediment. Appl Environ Microbiol 2018; 84:e01572-18. [PMID: 30097443 PMCID: PMC6182907 DOI: 10.1128/aem.01572-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 08/03/2018] [Indexed: 11/20/2022] Open
Abstract
The energetic situation of terminal fermentations in methanogenesis was analyzed by pool size determinations in sediment cores taken in the oligotrophic Lake Constance, Germany. Distribution profiles of fermentation intermediates and products were measured at three different water depths (2, 10, and 80 m). Methane concentrations were constant below 10 cm of sediment depth. Within the methanogenic zone, concentrations of formate, acetate, propionate, and butyrate varied between 1 and 40 μM, and hydrogen was between 0.5 and 5 Pa. From the distribution profiles of the fermentation intermediates, Gibbs free energy changes for their interconversion were calculated. Pool sizes of formate and hydrogen were energetically nearly equivalent, with -5 ± 5 kJ per mol difference of free energy change (ΔG) for a hypothetical conversion of formate to hydrogen plus CO2 The ΔG values for conversion of fatty acids to methanogenic substrates and their further conversion to methane and CO2 were calculated with hydrogen and with formate as intermediates. Syntrophic propionate oxidation reached energetic equilibrium with formate as the sole electron carrier but was sufficiently exergonic if at least some of the electrons were transferred via hydrogen. The energetic consequences of formate versus hydrogen transfer in secondary and methanogenic fermentations indicate that both carrier systems are probably used simultaneously to optimize the energy yields for the partners involved.IMPORTANCE In the terminal steps of methane formation in freshwater lake sediments, fermenting bacteria cooperate syntrophically with methanogens and homoacetogens at minimum energy increments via interspecies electron transfer. The energy yields of the partner organisms in these cooperations have so far been calculated based mainly on in situ hydrogen partial pressures. In the present study, we also analyzed pools of formate as an alternative electron carrier in sediment cores of an oligotrophic lake. The formate and hydrogen pools appeared to be energetically nearly equivalent and are likely to be used simultaneously for interspecies electron transfer. Calculations of reaction energies of the partners involved suggest that propionate degradation may also proceed through the Smithella pathway, which converts propionate via butyrate and acetate to three acetate residues, thus circumventing one energetically difficult fatty acid oxidation step.
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Affiliation(s)
- Dominik Montag
- Department of Biology, University of Konstanz, Constance, Germany
| | - Bernhard Schink
- Department of Biology, University of Konstanz, Constance, Germany
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Röhlen DL, Pilas J, Dahmen M, Keusgen M, Selmer T, Schöning MJ. Toward a Hybrid Biosensor System for Analysis of Organic and Volatile Fatty Acids in Fermentation Processes. Front Chem 2018; 6:284. [PMID: 30065922 PMCID: PMC6056648 DOI: 10.3389/fchem.2018.00284] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 06/22/2018] [Indexed: 11/13/2022] Open
Abstract
Monitoring of organic acids (OA) and volatile fatty acids (VFA) is crucial for the control of anaerobic digestion. In case of unstable process conditions, an accumulation of these intermediates occurs. In the present work, two different enzyme-based biosensor arrays are combined and presented for facile electrochemical determination of several process-relevant analytes. Each biosensor utilizes a platinum sensor chip (14 × 14 mm2) with five individual working electrodes. The OA biosensor enables simultaneous measurement of ethanol, formate, d- and l-lactate, based on a bi-enzymatic detection principle. The second VFA biosensor provides an amperometric platform for quantification of acetate and propionate, mediated by oxidation of hydrogen peroxide. The cross-sensitivity of both biosensors toward potential interferents, typically present in fermentation samples, was investigated. The potential for practical application in complex media was successfully demonstrated in spiked sludge samples collected from three different biogas plants. Thereby, the results obtained by both of the biosensors were in good agreement to the applied reference measurements by photometry and gas chromatography, respectively. The proposed hybrid biosensor system was also used for long-term monitoring of a lab-scale biogas reactor (0.01 m3) for a period of 2 months. In combination with typically monitored parameters, such as gas quality, pH and FOS/TAC (volatile organic acids/total anorganic carbonate), the amperometric measurements of OA and VFA concentration could enhance the understanding of ongoing fermentation processes.
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Affiliation(s)
| | - Johanna Pilas
- Institute of Nano- and Biotechnologies, FH Aachen, Jülich, Germany
- Institute of Pharmaceutical Chemistry, Philipps-Universität Marburg, Marburg, Germany
| | | | - Michael Keusgen
- Institute of Pharmaceutical Chemistry, Philipps-Universität Marburg, Marburg, Germany
| | - Thorsten Selmer
- Institute of Nano- and Biotechnologies, FH Aachen, Jülich, Germany
| | - Michael J. Schöning
- Institute of Nano- and Biotechnologies, FH Aachen, Jülich, Germany
- Institute of Complex Systems 8, Forschungszentrum Jülich, Jülich, Germany
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Paolini V, Petracchini F, Carnevale M, Gallucci F, Perilli M, Esposito G, Segreto M, Occulti LG, Scaglione D, Ianniello A, Frattoni M. Characterisation and cleaning of biogas from sewage sludge for biomethane production. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 217:288-296. [PMID: 29614477 DOI: 10.1016/j.jenvman.2018.03.113] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 02/19/2018] [Accepted: 03/25/2018] [Indexed: 06/08/2023]
Abstract
This study investigates the conversion of sewage sludge from wastewater treatment plants (WWTP) into biomethane for automotive fuel or grid injection. A prototype plant was monitored in Northern Italy, based on vacuum swing adsorption (VSA) on synthetic zeolite 13×: this biogas upgrading method is similar to pressure swing adsorption (PSA) and commonly used for other kinds of biomass. Measurements of biogas inlet, biomethane outlet and off-gas were performed including CH4, CO2, CO, H2, O2, N2, HCl, HF, NH3, H2S and volatile organic compounds (VOCs). Critical levels were observed in the biogas for of H2S and HCl, whose concentrations were 1570 and 26.8 mg m-3, respectively. On the other hand, the concentration of halogenated VOCs (including tetrachloroethylene and traces of perfluoroalkilated substances, PFAS) and mercaptans were relatively low. A simultaneous and reversible adsorption on 13× zeolite was achieved for H2S and CO2, and carbon filters played a minor role in desulfurisation. The presence of HCl is due to clarifying agents, and its removal is necessary in order to meet the required biomethane characteristics: an additional carbon-supported basic adsorbent was successfully used to remove this contaminant. This study also highlights the interference of CO2 towards HCl if sampling is performed in compliance with the new EU standard for biomethane. High total volatile silicon (TVS) was confirmed in sewage sludge biogas, with a major contribution of siloxane D5: the suitability of this compound as an indicator of total siloxanes is discussed. Results demonstrate that volatile methyl siloxanes (VMS) do not represent a critical issue for the VSA upgrading methodology.
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Affiliation(s)
- Valerio Paolini
- National Research Council of Italy, Institute of Atmospheric Pollution Research, via Salaria 29,300, 00015 Monterotondo, Italy.
| | - Francesco Petracchini
- National Research Council of Italy, Institute of Atmospheric Pollution Research, via Salaria 29,300, 00015 Monterotondo, Italy
| | - Monica Carnevale
- Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria, Unità di Ricerca per l'Ingegneria Agraria, Via della Pascolare 16, 00015 Monterotondo, Italy
| | - Francesco Gallucci
- Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria, Unità di Ricerca per l'Ingegneria Agraria, Via della Pascolare 16, 00015 Monterotondo, Italy
| | - Mattia Perilli
- National Research Council of Italy, Institute of Atmospheric Pollution Research, via Salaria 29,300, 00015 Monterotondo, Italy
| | - Giulio Esposito
- National Research Council of Italy, Institute of Atmospheric Pollution Research, via Salaria 29,300, 00015 Monterotondo, Italy
| | - Marco Segreto
- National Research Council of Italy, Institute of Atmospheric Pollution Research, via Salaria 29,300, 00015 Monterotondo, Italy
| | | | - Davide Scaglione
- Water Agency of Milan Gruppo CAP S.p.A., Via del Mulino 2, 20090 Assago, Italy
| | - Antonietta Ianniello
- National Research Council of Italy, Institute of Atmospheric Pollution Research, via Salaria 29,300, 00015 Monterotondo, Italy
| | - Massimiliano Frattoni
- National Research Council of Italy, Institute of Atmospheric Pollution Research, via Salaria 29,300, 00015 Monterotondo, Italy
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Müller N, Timmers P, Plugge CM, Stams AJM, Schink B. Syntrophy in Methanogenic Degradation. (ENDO)SYMBIOTIC METHANOGENIC ARCHAEA 2018. [DOI: 10.1007/978-3-319-98836-8_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Losey NA, Mus F, Peters JW, Le HM, McInerney MJ. Syntrophomonas wolfei Uses an NADH-Dependent, Ferredoxin-Independent [FeFe]-Hydrogenase To Reoxidize NADH. Appl Environ Microbiol 2017; 83:e01335-17. [PMID: 28802265 PMCID: PMC5626996 DOI: 10.1128/aem.01335-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 07/29/2017] [Indexed: 12/19/2022] Open
Abstract
Syntrophomonas wolfei syntrophically oxidizes short-chain fatty acids (four to eight carbons in length) when grown in coculture with a hydrogen- and/or formate-using methanogen. The oxidation of 3-hydroxybutyryl-coenzyme A (CoA), formed during butyrate metabolism, results in the production of NADH. The enzyme systems involved in NADH reoxidation in S. wolfei are not well understood. The genome of S. wolfei contains a multimeric [FeFe]-hydrogenase that may be a mechanism for NADH reoxidation. The S. wolfei genes for the multimeric [FeFe]-hydrogenase (hyd1ABC; SWOL_RS05165, SWOL_RS05170, SWOL_RS05175) and [FeFe]-hydrogenase maturation proteins (SWOL_RS05180, SWOL_RS05190, SWOL_RS01625) were coexpressed in Escherichia coli, and the recombinant Hyd1ABC was purified and characterized. The purified recombinant Hyd1ABC was a heterotrimer with an αβγ configuration and a molecular mass of 115 kDa. Hyd1ABC contained 29.2 ± 1.49 mol of Fe and 0.7 mol of flavin mononucleotide (FMN) per mole enzyme. The purified, recombinant Hyd1ABC reduced NAD+ and oxidized NADH without the presence of ferredoxin. The HydB subunit of the S. wolfei multimeric [FeFe]-hydrogenase lacks two iron-sulfur centers that are present in known confurcating NADH- and ferredoxin-dependent [FeFe]-hydrogenases. Hyd1ABC is a NADH-dependent hydrogenase that produces hydrogen from NADH without the need of reduced ferredoxin, which differs from confurcating [FeFe]-hydrogenases. Hyd1ABC provides a mechanism by which S. wolfei can reoxidize NADH produced during syntrophic butyrate oxidation when low hydrogen partial pressures are maintained by a hydrogen-consuming microorganism.IMPORTANCE Our work provides mechanistic understanding of the obligate metabolic coupling that occurs between hydrogen-producing fatty and aromatic acid-degrading microorganisms and their hydrogen-consuming partners in the process called syntrophy (feeding together). The multimeric [FeFe]-hydrogenase used NADH without the involvement of reduced ferredoxin. The multimeric [FeFe]-hydrogenase would produce hydrogen from NADH only when hydrogen concentrations were low. Hydrogen production from NADH by Syntrophomonas wolfei would likely cease before any detectable amount of cell growth occurred. Thus, continual hydrogen production requires the presence of a hydrogen-consuming partner to keep hydrogen concentrations low and explains, in part, the obligate requirement that S. wolfei has for a hydrogen-consuming partner organism during growth on butyrate. We have successfully expressed genes encoding a multimeric [FeFe]-hydrogenase in E. coli, demonstrating that such an approach can be advantageous to characterize complex redox proteins from difficult-to-culture microorganisms.
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Affiliation(s)
- Nathaniel A Losey
- Department of Plant Biology and Microbiology, University of Oklahoma, Norman, Oklahoma, USA
| | - Florence Mus
- Department of Chemistry and Biochemistry, Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - John W Peters
- Department of Chemistry and Biochemistry, Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Huynh M Le
- Department of Plant Biology and Microbiology, University of Oklahoma, Norman, Oklahoma, USA
| | - Michael J McInerney
- Department of Plant Biology and Microbiology, University of Oklahoma, Norman, Oklahoma, USA
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Schink B, Montag D, Keller A, Müller N. Hydrogen or formate: Alternative key players in methanogenic degradation. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:189-202. [PMID: 28205388 DOI: 10.1111/1758-2229.12524] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Hydrogen and formate are important electron carriers in methanogenic degradation in anoxic environments such as sediments, sewage sludge digestors and biogas reactors. Especially in the terminal steps of methanogenesis, they determine the energy budgets of secondary (syntrophically) fermenting bacteria and their methanogenic partners. The literature provides considerable data on hydrogen pool sizes in such habitats, but little data exist for formate concentrations due to technical difficulties in formate determination at low concentration. Recent evidence from biochemical and molecular biological studies indicates that several secondary fermenters can use both hydrogen and formate for electron release, and may do so even simultaneously. Numerous strictly anaerobic bacteria contain enzymes which equilibrate hydrogen and formate pools to energetically equal values, and recent measurements in sewage digestors and biogas reactors indicate that - beyond occasional fluctuations - the pool sizes of hydrogen and formate are indeed energetically nearly equivalent. Nonetheless, a thermophilic archaeon from a submarine hydrothermal vent, Thermococcus onnurineus, can obtain ATP from the conversion of formate to hydrogen plus bicarbonate at 80°C, indicating that at least in this extreme environment the pools of formate and hydrogen are likely to be sufficiently different to support such an unusual type of energy conservation.
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Affiliation(s)
- Bernhard Schink
- Department of Biology, Microbial Ecology, University of Konstanz, Konstanz, D-78457, Germany
| | - Dominik Montag
- Department of Biology, Microbial Ecology, University of Konstanz, Konstanz, D-78457, Germany
| | - Anja Keller
- Department of Biology, Microbial Ecology, University of Konstanz, Konstanz, D-78457, Germany
| | - Nicolai Müller
- Department of Biology, Microbial Ecology, University of Konstanz, Konstanz, D-78457, Germany
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Schnürer A. Biogas Production: Microbiology and Technology. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016; 156:195-234. [PMID: 27432246 DOI: 10.1007/10_2016_5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Biogas, containing energy-rich methane, is produced by microbial decomposition of organic material under anaerobic conditions. Under controlled conditions, this process can be used for the production of energy and a nutrient-rich residue suitable for use as a fertilising agent. The biogas can be used for production of heat, electricity or vehicle fuel. Different substrates can be used in the process and, depending on substrate character, various reactor technologies are available. The microbiological process leading to methane production is complex and involves many different types of microorganisms, often operating in close relationships because of the limited amount of energy available for growth. The microbial community structure is shaped by the incoming material, but also by operating parameters such as process temperature. Factors leading to an imbalance in the microbial community can result in process instability or even complete process failure. To ensure stable operation, different key parameters, such as levels of degradation intermediates and gas quality, are often monitored. Despite the fact that the anaerobic digestion process has long been used for industrial production of biogas, many questions need still to be resolved to achieve optimal management and gas yields and to exploit the great energy and nutrient potential available in waste material. This chapter discusses the different aspects that need to be taken into consideration to achieve optimal degradation and gas production, with particular focus on operation management and microbiology.
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Affiliation(s)
- Anna Schnürer
- Department of Microbiology, Swedish University of Agricultural Sciences, 7025, 750 07, Uppsala, Sweden.
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