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Sánchez-Sánchez C, Aranda-Medina M, Rodríguez A, Hernández A, Córdoba MG, Cuadros-Blázquez F, Ruiz-Moyano S. Development of real-time PCR methods for the quantification of Methanoculleus, Methanosarcina and Methanobacterium in anaerobic digestion. J Microbiol Methods 2022; 199:106529. [PMID: 35772572 DOI: 10.1016/j.mimet.2022.106529] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/18/2022] [Accepted: 06/22/2022] [Indexed: 12/27/2022]
Abstract
Anaerobic digestion is a growing technology to manage organic waste and produce bioenergy. To promote this technology, it is essential to know, at the molecular level, the dynamics of microbial communities, specifically the methanogenic community. In the present study, three primer pairs were selected from seven primer pairs which were designed and tested with different concentrations and conditions to detect Methanosarcina, Methanoculleus and Methanobacterium by real-time PCR based on the SYBR Green System. The functionality of the developed methods was demonstrated by the high linear relationship of the standard curves, and the specificity of each primer was empirically verified by testing DNA isolated from methane-producing and non-producing strains. These assays also exhibited good repeatability and reproducibility, which indicates the robustness of the methods. The described primers were successfully used to investigate the methanogenic communities of 10 samples from an anaerobic co-digestion. The genus Methanosarcina was the dominant methanogenic group.
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Affiliation(s)
- Consolación Sánchez-Sánchez
- Departamento de Física Aplicada, Escuela de Ingenierías Agrarias, Universidad de Extremadura, Avda, de Adolfo Suárez S/n, 06007 Badajoz, Spain
| | - Mercedes Aranda-Medina
- Expresión Gráfica, Escuela de Ingenierías Industriales, Campus Universitario, Avda de Elvas sn, 06006 Badajoz, Spain
| | - Alicia Rodríguez
- Instituto Universitario de Investigación de Recursos Agrarios (INURA), Escuela de Ingenierías Agrarias, Universidad de Extremadura, Avda. Adolfo Suarez, s/n, 06071 Badajoz, Spain.
| | - Alejandro Hernández
- Instituto Universitario de Investigación de Recursos Agrarios (INURA), Escuela de Ingenierías Agrarias, Universidad de Extremadura, Avda. Adolfo Suarez, s/n, 06071 Badajoz, Spain
| | - María G Córdoba
- Instituto Universitario de Investigación de Recursos Agrarios (INURA), Escuela de Ingenierías Agrarias, Universidad de Extremadura, Avda. Adolfo Suarez, s/n, 06071 Badajoz, Spain
| | - Francisco Cuadros-Blázquez
- Departamento de Física Aplicada, Escuela de Ingenierías Agrarias, Universidad de Extremadura, Avda, de Adolfo Suárez S/n, 06007 Badajoz, Spain
| | - Santiago Ruiz-Moyano
- Instituto Universitario de Investigación de Recursos Agrarios (INURA), Escuela de Ingenierías Agrarias, Universidad de Extremadura, Avda. Adolfo Suarez, s/n, 06071 Badajoz, Spain
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2
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Mozhiarasi V. Overview of pretreatment technologies on vegetable, fruit and flower market wastes disintegration and bioenergy potential: Indian scenario. CHEMOSPHERE 2022; 288:132604. [PMID: 34678338 DOI: 10.1016/j.chemosphere.2021.132604] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 10/11/2021] [Accepted: 10/16/2021] [Indexed: 06/13/2023]
Abstract
Disposal of segregated organic fractions of centralized wholesale market wastes (i.e. vegetable, fruit and flower markets waste) in dumpsites/landfills are not only a serious issue but also underutilizes the huge potency of these organic wastes. Anaerobic digestion (AD) is a promising technology for converting organic wastes into methane, as a carbon-neutral alternative to conventional fuels. The major challenges related to the AD process are poor biodegradation of wastes and buffering capacity within the anaerobic digester that lowers the biogas yield. To accelerate biodegradation and to enhance the process efficacy of anaerobic digestion, several pretreatment technologies (mechanical, thermal, biological, chemical and combined pre-treatments) for organic wastes prior to the AD process were developed. This review article presents a comprehensive analysis of research updates in pretreatment techniques for vegetable, fruit and flower markets wastes for enhancing biogas yields during the AD process. The technological aspects of the pretreatment process are described and their efficiency comparison with the resultant process yields and environmental benefits are also discussed. The challenges and technical issues associated with each pretreatment and future research directions for overcoming the field implementation issues are also proposed.
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Affiliation(s)
- Velusamy Mozhiarasi
- CLRI Regional Centre Jalandhar, CSIR-Central Leather Research Institute, Jalandhar, 144021, Punjab, India.
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Kim SI, Chairattanawat C, Kim E, Hwang S. Shift in methanogenic community in protein degradation using different inocula. BIORESOURCE TECHNOLOGY 2021; 333:125145. [PMID: 33906017 DOI: 10.1016/j.biortech.2021.125145] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/31/2021] [Accepted: 04/02/2021] [Indexed: 06/12/2023]
Abstract
Anaerobic digestion (AD) of protein-rich wastes is problematic due to production of ammonia and hydrogen sulfide. In this work, eight inocula were used in batch AD of solutions of gelatin and gluten at 3 g COD substrate/1g VSS inoculum. AD plants from which inocula originated were treating food waste or food wastewater, wastewater sludge, or a combination of them. Inocula were evaluated by fitting methane production data using the modified Gompertz model. Sequencing of 16 s rRNA of microorganisms showed that Methanoculleus was dominant in inocula from plants that were treating food waste, and Methanosaeta was dominant in the others. The maximum methane production rate varied by a factor of three for each substrate: 2.734-7.438 mLCH4 gCOD-1 d-1 for gelatin, and 1.950 to 5.532 mLCH4 gCOD-1 d-1 for gluten. This study demonstrates that inoculum must be chosen appropriately when treating proteinaceous waste by AD.
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Affiliation(s)
- Su In Kim
- Division of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Chayanee Chairattanawat
- Division of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Eunji Kim
- Division of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Seokhwan Hwang
- Division of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 37673, Republic of Korea.
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4
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Han R, Zhu D, Xing J, Li Q, Li Y, Chen L. The effect of temperature fluctuation on the microbial diversity and community structure of rural household biogas digesters at Qinghai Plateau. Arch Microbiol 2019; 202:525-538. [PMID: 31712862 DOI: 10.1007/s00203-019-01767-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 10/27/2019] [Accepted: 10/31/2019] [Indexed: 01/04/2023]
Abstract
Seasonal temperature-fluctuation has been regarded as a key environmental factor affecting rural biogas fermentation yields. The present study investigated the impact of seasonal temperature-fluctuation on operating-temperatures and biogas production in rural household digesters at Qinghai Plateau and revealed the related changes in microbial diversity and community structure by 16S rRNA gene high-throughput sequencing (HTS) analysis. Our results showed closely positive correlation between operating-temperatures and biogas production. HTS analysis indicated the highest diversity for bacteria community in autumn (at highest operating-temperatures) and late winter (at lowest operating-temperatures) and for archaea community only in autumn. HTS analysis classified bacteria into 21 phyla and 346 genera with the most predominant phyla Firmicutes, Bacteroidetes and Proteobacteria (> 72.4% in total) and the most predominant genera Proteiniphilum, Clostridium sensustricto 1, Petrimonas, Pseudomonas and Fastidiosipila (37.09-38.61% in total). HTS analysis also revealed two main archaea orders (Methanomicrobiales and Methanobacteriales) and one predominant genus Methanogenium to support plateau biogas fermentation. Especially, a remarkable impact of temperature on the community abundances of bacteria phyla Synergistetes and archaea genera Methanogenium and Thermogymnomonas was observed, and such microbial community structure changes were positively consistent with the biogas production. The present work provided the first set of evidences to link temperature-controlled modulation of microbial community structure with rural household biogas production at Qinghai Plateau.
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Affiliation(s)
- Rui Han
- Qinghai Key Laboratory of Vegetable Genetics and Physiology, Academy of Agriculture and Forestry, Qinghai University, Ningda Road 253, Xining, Qinghai, 810016, China
| | - Derui Zhu
- Research Center of Basic Medical Sciences, Qinghai University Medical College, Xining, Qinghai, 810006, China.
| | - Jiangwa Xing
- Research Center of Basic Medical Sciences, Qinghai University Medical College, Xining, Qinghai, 810006, China
| | - Quanhui Li
- Qinghai Key Laboratory of Vegetable Genetics and Physiology, Academy of Agriculture and Forestry, Qinghai University, Ningda Road 253, Xining, Qinghai, 810016, China
| | - Yi Li
- Qinghai Key Laboratory of Vegetable Genetics and Physiology, Academy of Agriculture and Forestry, Qinghai University, Ningda Road 253, Xining, Qinghai, 810016, China
| | - Laisheng Chen
- Qinghai Key Laboratory of Vegetable Genetics and Physiology, Academy of Agriculture and Forestry, Qinghai University, Ningda Road 253, Xining, Qinghai, 810016, China.
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Utilization of Food and Agricultural Residues for a Flexible Biogas Production: Process Stability and Effects on Needed Biogas Storage Capacities. ENERGIES 2019. [DOI: 10.3390/en12142678] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Biogas plants can contribute to future energy systems’ stability through flexible power generation. To provide power flexibly, a demand-oriented biogas supply is necessary, which may be ensured by applying flexible feeding strategies. In this study, the impacts of applying three different feeding strategies (1x, 3x and 9x feeding per day) on the biogas and methane production and process stability parameters were determined for a biogas plant with a focus on waste treatment. Two feedstocks that differed in (1) high fat and (2) higher carbohydrate content were investigated during semi-continuous fermentation tests. Measurements of the short chain fatty acids concentration, pH value, TVA/TIC ratio and total ammonium and ammonia content along with a molecular biology analysis were conducted to assess the effects on process stability. The results show that flexible biogas production can be obtained without negative impacts on the process performance and that production peaks in biogas and methane can be significantly shifted to another time by changing feeding intervals. Implementing the fermentation tests’ results into a biogas plant simulation model and an assessment of power generation scenarios focusing on peak-time power generation revealed a considerable reduction potential for the needed biogas storage capacity of up to 73.7%.
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6
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Maurus K, Ahmed S, Getz W, Kazda M. Sugar beet silage as highly flexible feedstock for on demand biogas production. SUGAR INDUSTRY-ZUCKERINDUSTRIE 2018. [DOI: 10.36961/si20165] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
On demand biogas production is a great option to complement solar and wind power for the energy revolution. Alternatives like feedstock management are important in order to avoid expensive and complex adjustments for gas storage systems. The use of sugar beet silage (S) is a good option because it mainly contains carbohydrates that are easily degradable.
Anaerobic digestion was performed for 63 days in four completely stirred tank reactors (CSTR) with different ratios of maize silage (M) and S. M given every hour was used as a base load for the fermentation and S was given two times a day every 12h. Biogas and methane production rates were measured every 5min in order to achieve data with high resolution. Also, pH value, VFA/TIC values and volatile fatty acids were measured during the experiment.
The process remained stable in CSTR1 (M:S1:0), CSTR2 (M:S6:1) and CSTR3 (M:S3:1). Instabilities occurred in CSTR4 (M:S1:3) after an operation time of 33 days.
Nevertheless, methane yields more than doubled for CSTR3 within 5min after the input of S. Use of sugar beet as a feedstock for biogas production is a further application for this agricultural commodity.
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Lecker B, Illi L, Lemmer A, Oechsner H. Biological hydrogen methanation - A review. BIORESOURCE TECHNOLOGY 2017; 245:1220-1228. [PMID: 28893503 DOI: 10.1016/j.biortech.2017.08.176] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/28/2017] [Accepted: 08/29/2017] [Indexed: 05/07/2023]
Abstract
Surplus energy out of fluctuating energy sources like wind and solar energy is strongly increasing. Biological hydrogen (H2) methanation (BHM) is a highly promising approach to move the type of energy from electricity to natural gas via electrolysis and the subsequent step of the Sabatier-reaction. This review provides an overview of the numerous studies concerning the topic of BHM. The technical and biological parameters regarding the research results of these studies are compared and analyzed hereafter. A holistic view on how to overcome physical limitations of the fermentation process, such as gas-liquid mass transfer or a rise of the pH value, and on the enhancement of environmental circumstances for the bacterial biomass are delivered within. With regards to ex-situ methanation, the evaluated studies show a distinct connection between methane production and the methane percentage in the off-gas.
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Affiliation(s)
- Bernhard Lecker
- University of Hohenheim, State Institute of Agricultural Engineering and Bioenergy, Garbenstraße 9, 70599 Stuttgart, Germany.
| | - Lukas Illi
- University of Hohenheim, State Institute of Agricultural Engineering and Bioenergy, Garbenstraße 9, 70599 Stuttgart, Germany
| | - Andreas Lemmer
- University of Hohenheim, State Institute of Agricultural Engineering and Bioenergy, Garbenstraße 9, 70599 Stuttgart, Germany
| | - Hans Oechsner
- University of Hohenheim, State Institute of Agricultural Engineering and Bioenergy, Garbenstraße 9, 70599 Stuttgart, Germany
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Steinmetz RLR, Mezzari MP, da Silva MLB, Kunz A, do Amaral AC, Tápparo DC, Soares HM. Enrichment and acclimation of an anaerobic mesophilic microorganism's inoculum for standardization of BMP assays. BIORESOURCE TECHNOLOGY 2016; 219:21-28. [PMID: 27474854 DOI: 10.1016/j.biortech.2016.07.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 07/04/2016] [Accepted: 07/09/2016] [Indexed: 05/23/2023]
Abstract
Appropriate enrichment of anaerobic microorganism's consortium is crucial for accurate biochemical methane potential (BMP) assays. An alternative method to produce and maintain a mesophilic methanogenic inoculum was demonstrated. Three sources of inoculum were mixed and acclimated for 857days in order to reach steady conditions (pH=7.90±0.46; VS/TS>50%; VFA/alkalinity=0.16±0.04gAcetic Acid/ [Formula: see text] ). Biogas yield >80% was obtained after 70days of inoculum acclimation in comparison to standard cellulose (>600mLN/gVS). Methanogen community analysis based on 16S rDNA of the inoculum revealed Archaea concentration of 3×10(12) gene copies/g (Methanobacteriales 8×10(10); Methanomicrobiales 8×10(10); and Methanosarcinales 4×10(11) gene copies/g). The proposed method for development and maintenance of microorganism enrichment inoculum demonstrates consistent BMP data which is a requirement for dependable prediction of biogas production at field scale operations.
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Affiliation(s)
| | | | | | - Airton Kunz
- Embrapa Suínos e Aves, BR 153 km 110, 89700-000 Concórdia, SC, Brazil; Universidade Estadual do Oeste do Paraná - UNIOESTE/CCET/PGEAGRI, 85819110, Cascavel, PR, Brazil.
| | | | - Deisi Cristina Tápparo
- Universidade Estadual do Oeste do Paraná - UNIOESTE/CCET/PGEAGRI, 85819110, Cascavel, PR, Brazil.
| | - Hugo Moreira Soares
- Universidade Federal de Santa Catarina - UFSC, Departamento de Engenharia Química, 88034001 Florianópolis, SC, Brazil.
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Lebuhn M, Derenkó J, Rademacher A, Helbig S, Munk B, Pechtl A, Stolze Y, Prowe S, Schwarz WH, Schlüter A, Liebl W, Klocke M. DNA and RNA Extraction and Quantitative Real-Time PCR-Based Assays for Biogas Biocenoses in an Interlaboratory Comparison. Bioengineering (Basel) 2016; 3:bioengineering3010007. [PMID: 28952569 PMCID: PMC5597165 DOI: 10.3390/bioengineering3010007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 12/24/2015] [Indexed: 01/17/2023] Open
Abstract
Five institutional partners participated in an interlaboratory comparison of nucleic acid extraction, RNA preservation and quantitative Real-Time PCR (qPCR) based assays for biogas biocenoses derived from different grass silage digesting laboratory and pilot scale fermenters. A kit format DNA extraction system based on physical and chemical lysis with excellent extraction efficiency yielded highly reproducible results among the partners and clearly outperformed a traditional CTAB/chloroform/isoamylalcohol based method. Analytical purpose, sample texture, consistency and upstream pretreatment steps determine the modifications that should be applied to achieve maximum efficiency in the trade-off between extract purity and nucleic acid recovery rate. RNA extraction was much more variable, and the destination of the extract determines the method to be used. RNA stabilization with quaternary ammonium salts was an as satisfactory approach as flash freezing in liquid N2. Due to co-eluted impurities, spectrophotometry proved to be of limited value for nucleic acid qualification and quantification in extracts obtained with the kit, and picoGreen® based quantification was more trustworthy. Absorbance at 230 nm can be extremely high in the presence of certain chaotropic guanidine salts, but guanidinium isothiocyanate does not affect (q)PCR. Absolute quantification by qPCR requires application of a reliable internal standard for which correct PCR efficiency and Y-intercept values are important and must be reported.
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Affiliation(s)
- Michael Lebuhn
- Bavarian State Research Center for Agriculture, Department for Quality Assurance and Analytics, Lange Point 6, 85354 Freising, Germany.
| | - Jaqueline Derenkó
- Leibniz Institute for Agricultural Engineering Potsdam-Bornim, Department Bioengineering, Max-Eyth-Allee 100, 14469 Potsdam, Germany.
| | - Antje Rademacher
- Leibniz Institute for Agricultural Engineering Potsdam-Bornim, Department Bioengineering, Max-Eyth-Allee 100, 14469 Potsdam, Germany.
| | - Susanne Helbig
- Beuth University of Applied Sciences, Department of Life Sciences and Technology, Luxemburger Strasse 10, 13353 Berlin, Germany.
| | - Bernhard Munk
- Bavarian State Research Center for Agriculture, Department for Quality Assurance and Analytics, Lange Point 6, 85354 Freising, Germany.
| | - Alexander Pechtl
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, D-85354 Freising-Weihenstephan, Germany.
| | - Yvonne Stolze
- Institute for Genome Research and Systems Biology, CeBiTec, Bielefeld University, Bielefeld, Germany.
| | - Steffen Prowe
- Beuth University of Applied Sciences, Department of Life Sciences and Technology, Luxemburger Strasse 10, 13353 Berlin, Germany.
| | - Wolfgang H Schwarz
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, D-85354 Freising-Weihenstephan, Germany.
| | - Andreas Schlüter
- Institute for Genome Research and Systems Biology, CeBiTec, Bielefeld University, Bielefeld, Germany.
| | - Wolfgang Liebl
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, D-85354 Freising-Weihenstephan, Germany.
| | - Michael Klocke
- Leibniz Institute for Agricultural Engineering Potsdam-Bornim, Department Bioengineering, Max-Eyth-Allee 100, 14469 Potsdam, Germany.
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10
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Design and application of a synthetic DNA standard for real-time PCR analysis of microbial communities in a biogas digester. Appl Microbiol Biotechnol 2015; 99:6855-63. [DOI: 10.1007/s00253-015-6721-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 05/19/2015] [Accepted: 05/23/2015] [Indexed: 11/25/2022]
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11
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Lebuhn M, Weiß S, Munk B, Guebitz GM. Microbiology and Molecular Biology Tools for Biogas Process Analysis, Diagnosis and Control. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2015; 151:1-40. [PMID: 26337842 DOI: 10.1007/978-3-319-21993-6_1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Many biotechnological processes such as biogas production or defined biotransformations are carried out by microorganisms or tightly cooperating microbial communities. Process breakdown is the maximum credible accident for the operator. Any time savings that can be provided by suitable early-warning systems and allow for specific countermeasures are of great value. Process disturbance, frequently due to nutritional shortcomings, malfunction or operational deficits, is evidenced conventionally by process chemistry parameters. However, knowledge on systems microbiology and its function has essentially increased in the last two decades, and molecular biology tools, most of which are directed against nucleic acids, have been developed to analyze and diagnose the process. Some of these systems have been shown to indicate changes of the process status considerably earlier than the conventionally applied process chemistry parameters. This is reasonable because the triggering catalyst is determined, activity changes of the microbes that perform the reaction. These molecular biology tools have thus the potential to add to and improve the established process diagnosis system. This chapter is dealing with the actual state of the art of biogas process analysis in practice, and introduces molecular biology tools that have been shown to be of particular value in complementing the current systems of process monitoring and diagnosis, with emphasis on nucleic acid targeted molecular biology systems.
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Affiliation(s)
- Michael Lebuhn
- Department for Quality Assurance and Analytics, Bavarian State Research Center for Agriculture (LfL), Lange Point 6, 85354, Freising, Germany
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12
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Ultrasound-Enhanced Biogas Production from Different Substrates. PRODUCTION OF BIOFUELS AND CHEMICALS WITH ULTRASOUND 2015. [DOI: 10.1007/978-94-017-9624-8_8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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13
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Alvarado A, Montañez-Hernández LE, Palacio-Molina SL, Oropeza-Navarro R, Luévanos-Escareño MP, Balagurusamy N. Microbial trophic interactions and mcrA gene expression in monitoring of anaerobic digesters. Front Microbiol 2014; 5:597. [PMID: 25429286 PMCID: PMC4228917 DOI: 10.3389/fmicb.2014.00597] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 10/22/2014] [Indexed: 11/13/2022] Open
Abstract
Anaerobic digestion (AD) is a biological process where different trophic groups of microorganisms break down biodegradable organic materials in the absence of oxygen. A wide range of AD technologies is being used to convert livestock manure, municipal and industrial wastewaters, and solid organic wastes into biogas. AD gains importance not only because of its relevance in waste treatment but also because of the recovery of carbon in the form of methane, which is a renewable energy and is used to generate electricity and heat. Despite the advances on the engineering and design of new bioreactors for AD, the microbiology component always poses challenges. Microbiology of AD processes is complicated as the efficiency of the process depends on the interactions of various trophic groups involved. Due to the complex interdependence of microbial activities for the functionality of the anaerobic bioreactors, the genetic expression of mcrA, which encodes a key enzyme in methane formation, is proposed as a parameter to monitor the process performance in real time. This review evaluates the current knowledge on microbial groups, their interactions, and their relationship to the performance of anaerobic biodigesters with a focus on using mcrA gene expression as a tool to monitor the process.
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Affiliation(s)
- Alejandra Alvarado
- Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, TorreónMéxico
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, MarburgGermany
| | - Lilia E. Montañez-Hernández
- Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, TorreónMéxico
| | - Sandra L. Palacio-Molina
- Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, TorreónMéxico
| | | | - Miriam P. Luévanos-Escareño
- Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, TorreónMéxico
| | - Nagamani Balagurusamy
- Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, TorreónMéxico
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Okudoh V, Trois C, Workneh T, Schmidt S. The potential of cassava biomass and applicable technologies for sustainable biogas production in South Africa: A review. RENEWABLE AND SUSTAINABLE ENERGY REVIEWS 2014; 39:1035-1052. [DOI: 10.1016/j.rser.2014.07.142] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
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15
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Thermophilic microbial cellulose decomposition and methanogenesis pathways recharacterized by metatranscriptomic and metagenomic analysis. Sci Rep 2014; 4:6708. [PMID: 25330991 PMCID: PMC4204047 DOI: 10.1038/srep06708] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 10/02/2014] [Indexed: 02/01/2023] Open
Abstract
The metatranscriptomic recharacterization in the present study captured microbial enzymes at the unprecedented scale of 40,000 active genes belonged to 2,269 KEGG functions were identified. The novel information obtained herein revealed interesting patterns and provides an initial transcriptional insight into the thermophilic cellulose methanization process. Synergistic beta-sugar consumption by Thermotogales is crucial for cellulose hydrolysis in the thermophilic cellulose-degrading consortium because the primary cellulose degraders Clostridiales showed metabolic incompetence in subsequent beta-sugar pathways. Additionally, comparable transcription of putative Sus-like polysaccharide utilization loci (PULs) was observed in an unclassified order of Bacteroidetes suggesting the importance of PULs mechanism for polysaccharides breakdown in thermophilic systems. Despite the abundance of acetate as a fermentation product, the acetate-utilizing Methanosarcinales were less prevalent by 60% than the hydrogenotrophic Methanobacteriales. Whereas the aceticlastic methanogenesis pathway was markedly more active in terms of transcriptional activities in key genes, indicating that the less dominant Methanosarcinales are more active than their hydrogenotrophic counterparts in methane metabolism. These findings suggest that the minority of aceticlastic methanogens are not necessarily associated with repressed metabolism, in a pattern that was commonly observed in the cellulose-based methanization consortium, and thus challenge the causal likelihood proposed by previous studies.
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Isolation and differentiation of methanogenic Archaea from mesophilic corn-fed on-farm biogas plants with special emphasis on the genus Methanobacterium. Appl Microbiol Biotechnol 2014; 98:5719-35. [DOI: 10.1007/s00253-014-5652-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 02/14/2014] [Accepted: 02/27/2014] [Indexed: 01/02/2023]
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17
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Nikolausz M, Walter RFH, Sträuber H, Liebetrau J, Schmidt T, Kleinsteuber S, Bratfisch F, Günther U, Richnow HH. Evaluation of stable isotope fingerprinting techniques for the assessment of the predominant methanogenic pathways in anaerobic digesters. Appl Microbiol Biotechnol 2013; 97:2251-62. [DOI: 10.1007/s00253-012-4657-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 12/14/2012] [Accepted: 12/15/2012] [Indexed: 11/24/2022]
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18
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Traversi D, Villa S, Lorenzi E, Degan R, Gilli G. Application of a real-time qPCR method to measure the methanogen concentration during anaerobic digestion as an indicator of biogas production capacity. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2012; 111:173-177. [PMID: 22910214 DOI: 10.1016/j.jenvman.2012.07.021] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2011] [Revised: 07/10/2012] [Accepted: 07/23/2012] [Indexed: 06/01/2023]
Abstract
Biogas is an energy source that is produced via the anaerobic digestion of various organic materials, including waste-water sludge and organic urban wastes. Among the microorganisms involved in digestion, methanogens are the major microbiological group responsible for methane production. To study the microbiological equilibrium in an anaerobic reactor, we detected the methanogen concentration during wet digestion processes fed with pre-treated urban organic waste and waste-water sludge. Two different pre-treatments were used in successive experimental digestions: pressure-extrusion and turbo-mixing. Chemical parameters were collected to describe the process and its production. The method used is based on real-time quantitative PCR (RT-qPCR) with the functional gene mcrA as target. First, we evaluated the validity of the analyses. Next, we applied this method to 50 digestate samples and then we performed a statistical analysis. A positive and significant correlation between the biogas production rate and methanogen abundance was observed (r = 0.579, p < 0.001). This correlation holds both when considering all of the collected data and when the two data sets are separated. The pressure-extrusion pre-treatment allowed to obtain the higher methane amount and also the higher methanogen presence (F = 41.190, p < 0.01). Moreover a higher mean methanogen concentration was observed for production rate above than of 0.6 m(3) biogas/kg TVS (F = 7.053; p < 0.05). The applied method is suitable to describe microbiome into the anaerobic reactor, moreover methanogen concentration may have potential for use as a digestion optimisation tool.
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Affiliation(s)
- Deborah Traversi
- Department of Public Health and Microbiology, University of the Study of Turin, Via Santena 5 bis, 10126 Turin, Italy.
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19
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Rademacher A, Zakrzewski M, Schlüter A, Schönberg M, Szczepanowski R, Goesmann A, Pühler A, Klocke M. Characterization of microbial biofilms in a thermophilic biogas system by high-throughput metagenome sequencing. FEMS Microbiol Ecol 2011; 79:785-99. [PMID: 22126587 DOI: 10.1111/j.1574-6941.2011.01265.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 11/16/2011] [Accepted: 11/16/2011] [Indexed: 11/28/2022] Open
Abstract
DNAs of two biofilms of a thermophilic two-phase leach-bed biogas reactor fed with rye silage and winter barley straw were sequenced by 454-pyrosequencing technology to assess the biofilm-based microbial community and their genetic potential for anaerobic digestion. The studied biofilms matured on the surface of the substrates in the hydrolysis reactor (HR) and on the packing in the anaerobic filter reactor (AF). The classification of metagenome reads showed Clostridium as most prevalent bacteria in the HR, indicating a predominant role for plant material digestion. Notably, insights into the genetic potential of plant-degrading bacteria were determined as well as further bacterial groups, which may assist Clostridium in carbohydrate degradation. Methanosarcina and Methanothermobacter were determined as most prevalent methanogenic archaea. In consequence, the biofilm-based methanogenesis in this system might be driven by the hydrogenotrophic pathway but also by the aceticlastic methanogenesis depending on metabolite concentrations such as the acetic acid concentration. Moreover, bacteria, which are capable of acetate oxidation in syntrophic interaction with methanogens, were also predicted. Finally, the metagenome analysis unveiled a large number of reads with unidentified microbial origin, indicating that the anaerobic degradation process may also be conducted by up to now unknown species.
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Affiliation(s)
- Antje Rademacher
- Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V. (ATB), Abteilung Bioverfahrenstechnik, Potsdam, Germany
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20
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Neumann L, Scherer P. Impact of bioaugmentation by compost on the performance and ecology of an anaerobic digester fed with energy crops. BIORESOURCE TECHNOLOGY 2011; 102:2931-2935. [PMID: 21145230 DOI: 10.1016/j.biortech.2010.11.068] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 11/14/2010] [Accepted: 11/16/2010] [Indexed: 05/30/2023]
Abstract
The influence of compost as inoculum during continuous anaerobic digestion of fodder beet silage was studied over 330 days. Two simultaneously driven mesophilic fermentors (Inoc-1/Inoc-2) were inoculated with manure and sewage sludge. Only the digester Inoc-2 was inoculated additionally with compost. After 160 days fermentor Inoc-2 reached a hydraulic retention time (HRT) around 15 days whereas Inoc-1 remained at a HRT of 40d. After changing the substrate feed from one to three times a day both digesters stabilised at a shorter HRT; Inoc-2 at 10 days and Inoc-1 around 20 days. An additional inoculation of fermentor Inoc-1 by compost shortened the HRT to 10 days and revealed a minor increased gas production of about 6%. Fluorescence in situ hybridization indicated that probably an archaeal population shift was responsible for the observed stimulations. An addition of compost induced a methanogenic community change towards hydrogenotrophic methanogens.
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Affiliation(s)
- L Neumann
- Hamburg University of Applied Sciences, Laboratory of Applied Microbiology, Hamburg, Germany.
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21
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Munk B, Bauer C, Gronauer A, Lebuhn M. Population dynamics of methanogens during acidification of biogas fermenters fed with maize silage. Eng Life Sci 2010. [DOI: 10.1002/elsc.201000056] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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22
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Zverlov VV, Hiegl W, Köck DE, Kellermann J, Köllmeier T, Schwarz WH. Hydrolytic bacteria in mesophilic and thermophilic degradation of plant biomass. Eng Life Sci 2010. [DOI: 10.1002/elsc.201000059] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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23
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Mesophilic fermentation of renewable biomass: does hydraulic retention time regulate methanogen diversity? Appl Environ Microbiol 2010; 76:6322-6. [PMID: 20675458 DOI: 10.1128/aem.00927-10] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The present long-term study (about 1,100 days) monitored the diversity of methanogens during the mesophilic, anaerobic digestion of beet silage. Six fermentor samples were analyzed by ribosomal RNA gene restriction analysis, fluorescence in situ hybridization, and fluorescence microscopy. Hydrogenotrophic methanogens dominated within the population in all samples analyzed. Multidimensional scaling revealed that a rapid decrease in hydraulic retention time resulted in increased species richness, which in turn led to slightly higher CH(4) yields.
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24
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Nettmann E, Bergmann I, Pramschüfer S, Mundt K, Plogsties V, Herrmann C, Klocke M. Polyphasic analyses of methanogenic archaeal communities in agricultural biogas plants. Appl Environ Microbiol 2010; 76:2540-8. [PMID: 20154117 PMCID: PMC2849221 DOI: 10.1128/aem.01423-09] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Accepted: 02/02/2010] [Indexed: 11/20/2022] Open
Abstract
Knowledge of the microbial consortia participating in the generation of biogas, especially in methane formation, is still limited. To overcome this limitation, the methanogenic archaeal communities in six full-scale biogas plants supplied with different liquid manures and renewable raw materials as substrates were analyzed by a polyphasic approach. Fluorescence in situ hybridization (FISH) was carried out to quantify the methanogenic Archaea in the reactor samples. In addition, quantitative real-time PCR (Q-PCR) was used to support and complete the FISH analysis. Five of the six biogas reactors were dominated by hydrogenotrophic Methanomicrobiales. The average values were between 60 to 63% of archaeal cell counts (FISH) and 61 to 99% of archaeal 16S rRNA gene copies (Q-PCR). Within this order, Methanoculleus was found to be the predominant genus as determined by amplified rRNA gene restriction analysis. The aceticlastic family Methanosaetaceae was determined to be the dominant methanogenic group in only one biogas reactor, with average values for Q-PCR and FISH between 64% and 72%. Additionally, in three biogas reactors hitherto uncharacterized but potentially methanogenic species were detected. They showed closest accordance with nucleotide sequences of the hitherto unclassified CA-11 (85%) and ARC-I (98%) clusters. These results point to hydrogenotrophic methanogenesis as a predominant pathway for methane synthesis in five of the six analyzed biogas plants. In addition, a correlation between the absence of Methanosaetaceae in the biogas reactors and high concentrations of total ammonia (sum of NH(3) and NH(4)(+)) was observed.
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MESH Headings
- Ammonia/metabolism
- Archaea/classification
- Archaea/genetics
- Archaea/metabolism
- Biofuels/microbiology
- Bioreactors/microbiology
- DNA, Archaeal/chemistry
- DNA, Archaeal/genetics
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- Genes, rRNA
- Hydrogen/metabolism
- In Situ Hybridization, Fluorescence
- Methane/metabolism
- Molecular Sequence Data
- RNA, Archaeal/genetics
- RNA, Ribosomal, 16S/genetics
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- E. Nettmann
- Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Bioverfahrenstechnik, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Technikbewertung und Stoffkreisläufe, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Technische Universität Berlin, Fakultät 3, Institut für Technischen Umweltschutz, Fachgebiet Umweltmikrobiologie, Franklinstrasse 29, D-10587 Berlin, Germany, Beuth Hochschule für Technik Berlin, Fachbereich Life Sciences and Technology, Lütticher Straße 38, D-13353 Berlin, Germany, Humboldt Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, Invalidenstraße 42, D-10099 Berlin, Germany
| | - I. Bergmann
- Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Bioverfahrenstechnik, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Technikbewertung und Stoffkreisläufe, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Technische Universität Berlin, Fakultät 3, Institut für Technischen Umweltschutz, Fachgebiet Umweltmikrobiologie, Franklinstrasse 29, D-10587 Berlin, Germany, Beuth Hochschule für Technik Berlin, Fachbereich Life Sciences and Technology, Lütticher Straße 38, D-13353 Berlin, Germany, Humboldt Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, Invalidenstraße 42, D-10099 Berlin, Germany
| | - S. Pramschüfer
- Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Bioverfahrenstechnik, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Technikbewertung und Stoffkreisläufe, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Technische Universität Berlin, Fakultät 3, Institut für Technischen Umweltschutz, Fachgebiet Umweltmikrobiologie, Franklinstrasse 29, D-10587 Berlin, Germany, Beuth Hochschule für Technik Berlin, Fachbereich Life Sciences and Technology, Lütticher Straße 38, D-13353 Berlin, Germany, Humboldt Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, Invalidenstraße 42, D-10099 Berlin, Germany
| | - K. Mundt
- Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Bioverfahrenstechnik, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Technikbewertung und Stoffkreisläufe, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Technische Universität Berlin, Fakultät 3, Institut für Technischen Umweltschutz, Fachgebiet Umweltmikrobiologie, Franklinstrasse 29, D-10587 Berlin, Germany, Beuth Hochschule für Technik Berlin, Fachbereich Life Sciences and Technology, Lütticher Straße 38, D-13353 Berlin, Germany, Humboldt Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, Invalidenstraße 42, D-10099 Berlin, Germany
| | - V. Plogsties
- Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Bioverfahrenstechnik, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Technikbewertung und Stoffkreisläufe, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Technische Universität Berlin, Fakultät 3, Institut für Technischen Umweltschutz, Fachgebiet Umweltmikrobiologie, Franklinstrasse 29, D-10587 Berlin, Germany, Beuth Hochschule für Technik Berlin, Fachbereich Life Sciences and Technology, Lütticher Straße 38, D-13353 Berlin, Germany, Humboldt Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, Invalidenstraße 42, D-10099 Berlin, Germany
| | - C. Herrmann
- Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Bioverfahrenstechnik, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Technikbewertung und Stoffkreisläufe, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Technische Universität Berlin, Fakultät 3, Institut für Technischen Umweltschutz, Fachgebiet Umweltmikrobiologie, Franklinstrasse 29, D-10587 Berlin, Germany, Beuth Hochschule für Technik Berlin, Fachbereich Life Sciences and Technology, Lütticher Straße 38, D-13353 Berlin, Germany, Humboldt Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, Invalidenstraße 42, D-10099 Berlin, Germany
| | - M. Klocke
- Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Bioverfahrenstechnik, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V., Abteilung Technikbewertung und Stoffkreisläufe, Max-Eyth-Allee 100, D-14469 Potsdam, Germany, Technische Universität Berlin, Fakultät 3, Institut für Technischen Umweltschutz, Fachgebiet Umweltmikrobiologie, Franklinstrasse 29, D-10587 Berlin, Germany, Beuth Hochschule für Technik Berlin, Fachbereich Life Sciences and Technology, Lütticher Straße 38, D-13353 Berlin, Germany, Humboldt Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, Invalidenstraße 42, D-10099 Berlin, Germany
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Zhu C, Zhang J, Tang Y, Zhengkai X, Song R. Diversity of methanogenic archaea in a biogas reactor fed with swine feces as the mono-substrate by mcrA analysis. Microbiol Res 2010; 166:27-35. [PMID: 20116227 DOI: 10.1016/j.micres.2010.01.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 01/01/2010] [Accepted: 01/03/2010] [Indexed: 11/15/2022]
Abstract
Methanogenesis from the biomass in the anoxic biogas reactors is catalyzed by syntrophic cooperation between anaerobic bacteria, syntrophic acetogenic bacteria and methanogenic archaea. Understanding of microbial community composition within the biogas reactors may improve the methane production from biomass fermentation. In this study, methanogenic archaea diverity of a biogas reactor supplied with swine feces as mono-substrate under mesophilic conditions was investigated. Community composition was determined by analysis of methyl coenzyme reductase subunit A gene (mcrA) clone library consisting of 123 clones. Statistical analysis of mcrA library indicated that all major groups of methanogens from our biogas reactor were detected. In the library, 57.7% clones were affiliated to Methanobacteriales, 34.2% to Methanomicrobiales, 2.4% to Methanosarcinales and about 5.7% clones belonged to unclassified euryarchaeota. Over 90% of the methanogenic archaea from our biogas reactor were postulated to be hydrogenotrophic methanogens. Comparing with other previous studies reporting that hydrogenotrophic methanogens are dominant species in the biogas plants, this study firstly reported that Methanobacteriales instead of Methanomicrobiales are the most predominant methanogenic archaea in the biogas reactor fed with swine feces as sole substrate.
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Affiliation(s)
- Chenguang Zhu
- Shanghai Key Laboratory of Bio-energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China
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