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Dhull P, Kumar S, Yadav N, Lohchab RK. A comprehensive review on anaerobic digestion with focus on potential feedstocks, limitations associated and recent advances for biogas production. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-33736-6. [PMID: 38795291 DOI: 10.1007/s11356-024-33736-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 05/16/2024] [Indexed: 05/27/2024]
Abstract
With the escalating energy demand to accommodate the growing population and its needs along with the responsibility to mitigate climate change and its consequences, anaerobic digestion (AD) has become the potential approach to sustainably fulfil our demands and tackle environmental issues. Notably, a lot of attention has been drawn in recent years towards the production of biogas around the world in waste-to-energy perspective. Nevertheless, the progress of AD is hindered by several factors such as operating parameters, designing and the performance of AD reactors. Furthermore, the full potential of this approach is not fully realised yet due the dependence on people's acceptance and government policies. This article focuses on the different types of feedstocks and their biogas production potential. The feedstock selection is the basic and most important step for accessing the biogas yield. Furthermore, different stages of the AD process, design and the configuration of the biogas digester/reactors have been discussed to get better insight into process. The important aspect to talk about this process is its limitations associated which have been focused upon in detail. Biogas is considered to attain the sustainable development goals (SDG) proposed by United Nations. Therefore, the huge focus should be drawn towards its improvements to counter the limitation and makes it available to all the rural communities in developing countries and set-up the pilot scale AD plants in both developing and developed countries. In this regard, this article talks about the improvements and futures perspective related to the AD process and biogas enhancement.
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Affiliation(s)
- Paramjeet Dhull
- Department of Environmental Science & Engineering, Guru Jambheshwar University of Science & Technology, Hisar, Haryana, India
| | - Sachin Kumar
- Biochemical Conversion Division, Sardar Swaran Singh National Institute of Bio-Energy, Kapurthala, Punjab, 144601, India
| | - Nisha Yadav
- Biochemical Conversion Division, Sardar Swaran Singh National Institute of Bio-Energy, Kapurthala, Punjab, 144601, India
| | - Rajesh Kumar Lohchab
- Department of Environmental Science & Engineering, Guru Jambheshwar University of Science & Technology, Hisar, Haryana, India.
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2
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Chen Z, Ding Q, Ning X, Song Z, Gu J, Wang X, Sun W, Qian X, Hu T, Wei S, Xu L, Li Y, Zhou Z, Wei Y. Fe-Mn binary oxides improve the methanogenic performance and reduce the environmental health risks associated with antibiotic resistance genes during anaerobic digestion. JOURNAL OF HAZARDOUS MATERIALS 2024; 469:133921. [PMID: 38452670 DOI: 10.1016/j.jhazmat.2024.133921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/09/2024]
Abstract
Increasing evidence indicates that metal oxides can improve the methanogenic performance during anaerobic digestion (AD) of piggery wastewater. However, the impacts of composite metal oxides on the methanogenic performance and risk of antibiotic resistance gene (ARG) transmission during AD are not fully understood. In this study, different concentrations of Fe-Mn binary oxides (FMBO at 0, 250, 500, and 1000 mg/L) were added to AD to explore the effects of FMBO on the process. The methane yield was 7825.1 mL under FMBO at 250 mg/L, 35.2% higher than that with FMBO at 0 mg/L. PICRUSt2 functional predictions showed that FMBO promoted the oxidation of acetate and propionate, and the production of methane from the substrate, as well as increasing the abundances of most methanogens and genes encoding related enzymes. Furthermore, under FMBO at 250 mg/L, the relative abundances of 14 ARGs (excluding tetC and sul2) and four mobile gene elements (MGEs) decreased by 24.7% and 55.8%, respectively. Most of the changes in the abundances of ARGs were explained by microorganisms, especially Bacteroidetes (51.20%), followed by MGEs (11.98%). Thus, the methanogenic performance of AD improved and the risk of horizontal ARG transfer decreased with FMBO, especially at 250 mg/L.
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Affiliation(s)
- Zhihui Chen
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Qingling Ding
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xing Ning
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Zilin Song
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
| | - Jie Gu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China; Shaanxi Engineering Research Center of Utilization of Agricultural Waste Resources, Northwest A&F University, Yangling, Shaanxi 712100, China.
| | - Xiaojuan Wang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Wei Sun
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xun Qian
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Ting Hu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Shumei Wei
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Liang Xu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yuexuan Li
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Zhipeng Zhou
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yuan Wei
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China
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McDaniel EA, Scarborough M, Mulat DG, Lin X, Sampara PS, Olson HM, Young RP, Eder EK, Attah IK, Markillie LM, Hoyt DW, Lipton MS, Hallam SJ, Ziels RM. Diverse electron carriers drive syntrophic interactions in an enriched anaerobic acetate-oxidizing consortium. THE ISME JOURNAL 2023; 17:2326-2339. [PMID: 37880541 PMCID: PMC10689502 DOI: 10.1038/s41396-023-01542-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/09/2023] [Accepted: 10/11/2023] [Indexed: 10/27/2023]
Abstract
In many anoxic environments, syntrophic acetate oxidation (SAO) is a key pathway mediating the conversion of acetate into methane through obligate cross-feeding interactions between SAO bacteria (SAOB) and methanogenic archaea. The SAO pathway is particularly important in engineered environments such as anaerobic digestion (AD) systems operating at thermophilic temperatures and/or with high ammonia. Despite the widespread importance of SAOB to the stability of the AD process, little is known about their in situ physiologies due to typically low biomass yields and resistance to isolation. Here, we performed a long-term (300-day) continuous enrichment of a thermophilic (55 °C) SAO community from a municipal AD system using acetate as the sole carbon source. Over 80% of the enriched bioreactor metagenome belonged to a three-member consortium, including an acetate-oxidizing bacterium affiliated with DTU068 encoding for carbon dioxide, hydrogen, and formate production, along with two methanogenic archaea affiliated with Methanothermobacter_A. Stable isotope probing was coupled with metaproteogenomics to quantify carbon flux into each community member during acetate conversion and inform metabolic reconstruction and genome-scale modeling. This effort revealed that the two Methanothermobacter_A species differed in their preferred electron donors, with one possessing the ability to grow on formate and the other only consuming hydrogen. A thermodynamic analysis suggested that the presence of the formate-consuming methanogen broadened the environmental conditions where ATP production from SAO was favorable. Collectively, these results highlight how flexibility in electron partitioning during SAO likely governs community structure and fitness through thermodynamic-driven mutualism, shedding valuable insights into the metabolic underpinnings of this key functional group within methanogenic ecosystems.
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Affiliation(s)
- Elizabeth A McDaniel
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, Canada
| | - Matthew Scarborough
- Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT, USA
| | - Daniel Girma Mulat
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada
| | - Xuan Lin
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada
| | - Pranav S Sampara
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada
| | - Heather M Olson
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Robert P Young
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Elizabeth K Eder
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Isaac K Attah
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Lye Meng Markillie
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - David W Hoyt
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Mary S Lipton
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Steven J Hallam
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, Canada
- ECOSCOPE Training Program, The University of British Columbia, Vancouver, BC, Canada
- Graduate Program in Bioinformatics, The University of British Columbia, Vancouver, BC, Canada
- Genome Science and Technology Program, The University of British Columbia, Vancouver, BC, Canada
- Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - Ryan M Ziels
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada.
- Genome Science and Technology Program, The University of British Columbia, Vancouver, BC, Canada.
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Fuentes L, Palomo-Briones R, de Jesús Montoya-Rosales J, Braga L, Castelló E, Vesga A, Tapia-Venegas E, Razo-Flores E, Ecthebehere C. Knowing the enemy: homoacetogens in hydrogen production reactors. Appl Microbiol Biotechnol 2021; 105:8989-9002. [PMID: 34716461 DOI: 10.1007/s00253-021-11656-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/17/2021] [Accepted: 10/18/2021] [Indexed: 11/29/2022]
Abstract
One of the bottlenecks of the hydrogen production by dark fermentation is the low yields obtained because of the homoacetogenesis persistence, a metabolic pathway where H2 and CO2 are consumed to produce acetate. The central reactions of H2 production and homoacetogenesis are catalyzed by enzyme hydrogenase and the formyltetrahydrofolate synthetase, respectively. In this work, genes encoding for the formyltetrahydrofolate synthetase (fthfs) and hydrogenase (hydA) were used to investigate the diversity of homoacetogens as well as their phylogenetic relationships through quantitative PCR (qPCR) and next-generation amplicon sequencing. A total of 70 samples from 19 different H2-producing bioreactors with different configurations and operating conditions were analyzed. Quantification through qPCR showed that the abundance of fthfs and hydA was strongly associated with the type of substrate, organic loading rate, and H2 production performance. In particular, fthfs sequencing revealed that homoacetogens diversity was low with one or two dominant homoacetogens in each sample. Clostridium carboxivorans was detected in the reactors fed with agave hydrolisates; Acetobacterium woodii dominated in systems fed with glucose; Blautia coccoides and unclassified Sporoanaerobacter species were present in reactors fed with cheese whey; finally, Eubacterium limosum and Selenomonas sp. were co-dominant in reactors fed with glycerol. Altogether, quantification and sequencing analysis revealed that the occurrence of homoacetogenesis could take place due to (1) metabolic changes of H2-producing bacteria towards homoacetogenesis or (2) the displacement of H2-producing bacteria by homoacetogens. Overall, it was demonstrated that the fthfs gene was a suitable marker to investigate homoacetogens in H2-producing reactors. KEY POINTS: • qPCR and sequencing analysis revealed two homoacetogenesis phenomena. • fthfs gene was a suitable marker to investigate homoacetogens in H2 reactors.
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Affiliation(s)
- Laura Fuentes
- Laboratorio de Ecología Microbiana, Departamento de Bioquímica Y Genómica Microbiana, Instituto de Investigaciones Biológicas Clemente Estable, Av. Italia, 3318, Montevideo, Uruguay
| | - Rodolfo Palomo-Briones
- División de Ciencias Ambientales, Instituto Potosino de Investigación Científica Y Tecnológica A.C, Camino a La Presa San José No, 2055, Col. Lomas 4a Sección, C.P., 78216, San Luis Potosí, SLP, México
| | - José de Jesús Montoya-Rosales
- División de Ciencias Ambientales, Instituto Potosino de Investigación Científica Y Tecnológica A.C, Camino a La Presa San José No, 2055, Col. Lomas 4a Sección, C.P., 78216, San Luis Potosí, SLP, México
| | - Lucía Braga
- Laboratorio Bioprocesos Ambientales, Facultad de Ingeniería, Instituto de Ingeniería Química, Universidad de La República, Herrera Y Reissig, 565, Montevideo, Uruguay
| | - Elena Castelló
- Laboratorio Bioprocesos Ambientales, Facultad de Ingeniería, Instituto de Ingeniería Química, Universidad de La República, Herrera Y Reissig, 565, Montevideo, Uruguay
| | - Alejandra Vesga
- Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, 2085, Valparaíso, Av. Brasil, Chile
| | - Estela Tapia-Venegas
- Departamento de Medio Ambiente, Facultad de Ingeniería, Universidad de Playa Ancha Av, Leopoldo Carvallo 270, Valparaíso, Chile
| | - Elías Razo-Flores
- División de Ciencias Ambientales, Instituto Potosino de Investigación Científica Y Tecnológica A.C, Camino a La Presa San José No, 2055, Col. Lomas 4a Sección, C.P., 78216, San Luis Potosí, SLP, México
| | - Claudia Ecthebehere
- Laboratorio de Ecología Microbiana, Departamento de Bioquímica Y Genómica Microbiana, Instituto de Investigaciones Biológicas Clemente Estable, Av. Italia, 3318, Montevideo, Uruguay.
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Singh A, Moestedt J, Berg A, Schnürer A. Microbiological Surveillance of Biogas Plants: Targeting Acetogenic Community. Front Microbiol 2021; 12:700256. [PMID: 34484143 PMCID: PMC8415747 DOI: 10.3389/fmicb.2021.700256] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 07/21/2021] [Indexed: 11/15/2022] Open
Abstract
Acetogens play a very important role in anaerobic digestion and are essential in ensuring process stability. Despite this, targeted studies of the acetogenic community in biogas processes remain limited. Some efforts have been made to identify and understand this community, but the lack of a reliable molecular analysis strategy makes the detection of acetogenic bacteria tedious. Recent studies suggest that screening of bacterial genetic material for formyltetrahydrofolate synthetase (FTHFS), a key marker enzyme in the Wood-Ljungdahl pathway, can give a strong indication of the presence of putative acetogens in biogas environments. In this study, we applied an acetogen-targeted analyses strategy developed previously by our research group for microbiological surveillance of commercial biogas plants. The surveillance comprised high-throughput sequencing of FTHFS gene amplicons and unsupervised data analysis with the AcetoScan pipeline. The results showed differences in the acetogenic community structure related to feed substrate and operating parameters. They also indicated that our surveillance method can be helpful in the detection of community changes before observed changes in physico-chemical profiles, and that frequent high-throughput surveillance can assist in management towards stable process operation, thus improving the economic viability of biogas plants. To our knowledge, this is the first study to apply a high-throughput microbiological surveillance approach to visualise the potential acetogenic population in commercial biogas digesters.
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Affiliation(s)
- Abhijeet Singh
- Anaerobic Microbiology and Biotechnology Group, Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jan Moestedt
- Tekniska Verken i Linköping AB, Department R&D, Linköping, Sweden
| | | | - Anna Schnürer
- Anaerobic Microbiology and Biotechnology Group, Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
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6
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Singh A, Müller B, Schnürer A. Profiling temporal dynamics of acetogenic communities in anaerobic digesters using next-generation sequencing and T-RFLP. Sci Rep 2021; 11:13298. [PMID: 34168213 PMCID: PMC8225771 DOI: 10.1038/s41598-021-92658-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 06/14/2021] [Indexed: 02/06/2023] Open
Abstract
Acetogens play a key role in anaerobic degradation of organic material and in maintaining biogas process efficiency. Profiling this community and its temporal changes can help evaluate process stability and function, especially under disturbance/stress conditions, and avoid complete process failure. The formyltetrahydrofolate synthetase (FTHFS) gene can be used as a marker for acetogenic community profiling in diverse environments. In this study, we developed a new high-throughput FTHFS gene sequencing method for acetogenic community profiling and compared it with conventional terminal restriction fragment length polymorphism of the FTHFS gene, 16S rRNA gene-based profiling of the whole bacterial community, and indirect analysis via 16S rRNA profiling of the FTHFS gene-harbouring community. Analyses and method comparisons were made using samples from two laboratory-scale biogas processes, one operated under stable control and one exposed to controlled overloading disturbance. Comparative analysis revealed satisfactory detection of the bacterial community and its changes for all methods, but with some differences in resolution and taxonomic identification. FTHFS gene sequencing was found to be the most suitable and reliable method to study acetogenic communities. These results pave the way for community profiling in various biogas processes and in other environments where the dynamics of acetogenic bacteria have not been well studied.
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Affiliation(s)
- Abhijeet Singh
- grid.6341.00000 0000 8578 2742Anaerobic Microbiology and Biotechnology Group, Department of Molecular Sciences, Swedish University of Agricultural Sciences, Almas Allé 5, Box 7025, 750 07 Uppsala, Sweden
| | - Bettina Müller
- grid.6341.00000 0000 8578 2742Anaerobic Microbiology and Biotechnology Group, Department of Molecular Sciences, Swedish University of Agricultural Sciences, Almas Allé 5, Box 7025, 750 07 Uppsala, Sweden
| | - Anna Schnürer
- grid.6341.00000 0000 8578 2742Anaerobic Microbiology and Biotechnology Group, Department of Molecular Sciences, Swedish University of Agricultural Sciences, Almas Allé 5, Box 7025, 750 07 Uppsala, Sweden
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Singh A, Nylander JAA, Schnürer A, Bongcam-Rudloff E, Müller B. High-Throughput Sequencing and Unsupervised Analysis of Formyltetrahydrofolate Synthetase (FTHFS) Gene Amplicons to Estimate Acetogenic Community Structure. Front Microbiol 2020; 11:2066. [PMID: 32983047 PMCID: PMC7481360 DOI: 10.3389/fmicb.2020.02066] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/05/2020] [Indexed: 11/17/2022] Open
Abstract
The formyltetrahydrofolate synthetase (FTHFS) gene is a molecular marker of choice to study the diversity of acetogenic communities. However, current analyses are limited due to lack of a high-throughput sequencing approach for FTHFS gene amplicons and a dedicated bioinformatics pipeline for data analysis, including taxonomic annotation and visualization of the sequence data. In the present study, we combined the barcode approach for multiplexed sequencing with unsupervised data analysis to visualize acetogenic community structure. We used samples from a biogas digester to develop proof-of-principle for our combined approach. We successfully generated high-throughput sequence data for the partial FTHFS gene and performed unsupervised data analysis using the novel bioinformatics pipeline “AcetoScan” presented in this study, which resulted in taxonomically annotated OTUs, phylogenetic tree, abundance plots and diversity indices. The results demonstrated that high-throughput sequencing can be used to sequence the FTHFS amplicons from a pool of samples, while the analysis pipeline AcetoScan can be reliably used to process the raw sequence data and visualize acetogenic community structure. The method and analysis pipeline described in this paper can assist in the identification and quantification of known or potentially new acetogens. The AcetoScan pipeline is freely available at https://github.com/abhijeetsingh1704/AcetoScan.
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Affiliation(s)
- Abhijeet Singh
- Anaerobic Microbiology and Biotechnology Group, Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Johan A A Nylander
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden.,National Bioinformatics Infrastructure Sweden, SciLifeLab, Uppsala, Sweden
| | - Anna Schnürer
- Anaerobic Microbiology and Biotechnology Group, Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Erik Bongcam-Rudloff
- SLU-Global Bioinformatics Centre, Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Bettina Müller
- Anaerobic Microbiology and Biotechnology Group, Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Aoyagi T, Inaba T, Aizawa H, Mayumi D, Sakata S, Charfi A, Suh C, Lee JH, Sato Y, Ogata A, Habe H, Hori T. Unexpected diversity of acetate degraders in anaerobic membrane bioreactor treating organic solid waste revealed by high-sensitivity stable isotope probing. WATER RESEARCH 2020; 176:115750. [PMID: 32272322 DOI: 10.1016/j.watres.2020.115750] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 03/17/2020] [Accepted: 03/21/2020] [Indexed: 06/11/2023]
Abstract
In anaerobic membrane bioreactor (AnMBR) treating organic solid waste, acetate is one of the most important precursors to CH4. However, the identity and diversity of anaerobic acetate degraders are largely unknown, possibly due to their slow growth rates and low abundances. Here, we identified acetate-degrading microorganisms in the AnMBR sludges by high-sensitivity stable isotope probing. Degradation of the amended 13C-acetate coincided with production of 13CH4 and 13CO2 during the sludge incubation. High-throughput sequencing of RNA density fractions indicated that the aceticlastic and hydrogenotrophic methanogens, i.e., Methanosaeta sp. (acetate dissimilator) and Methanolinea sp. (acetate assimilator), incorporated 13C-acetate significantly. Remarkably, 22 bacterial species incorporating 13C-acetate were identified, whereas their majority was distantly related to the cultured representatives. Only two of them were the class Deltaproteobacteria-affiliated lineages with syntrophic volatile fatty acid oxidation activities. Phylogenetic tree analysis and population dynamics tracing revealed that novel species of the hydrolyzing and/or fermenting taxa, such as the phyla Bacteroidetes, Chloroflexi and Lentisphaerae, exhibited low relative abundances comparable to that of Methanolinea sp. (0.00011%) during the AnMBR operation, suggesting that these bacteria were involved in anaerobic acetate assimilation. Meanwhile, novel species of the phyla Firmicutes, Synergistetes and Caldiserica, the candidate phyla Aminicenantes and Atribacteria and the candidate division GOUTA4-related clade, as well as the known Deltaproteobacteria members, existed at relatively high abundances (0.00031%-0.31121%) in the reactor, suggesting that these bacterial species participated in anaerobic dissimilation of acetate, e.g., syntrophic acetate oxidation. The results of this study demonstrated the unexpected diversity and ecophysiological features of the anaerobic acetate degraders in the AnMBR treating organic solid waste.
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Affiliation(s)
- Tomo Aoyagi
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, 395-8569, Japan
| | - Tomohiro Inaba
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, 395-8569, Japan
| | - Hidenobu Aizawa
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, 395-8569, Japan
| | - Daisuke Mayumi
- Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, 305-8567, Japan
| | - Susumu Sakata
- Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, 305-8567, Japan
| | - Amine Charfi
- LG-Hitachi Water Solutions Co., Ltd., Gasan R&D Campus, 51, Gasan Digital 1-ro, Geumcheon-gu, Seoul, 08592, South Korea
| | - Changwon Suh
- LG-Hitachi Water Solutions Co., Ltd., Gasan R&D Campus, 51, Gasan Digital 1-ro, Geumcheon-gu, Seoul, 08592, South Korea
| | - Jong Hoon Lee
- LG-Hitachi Water Solutions Co., Ltd., Gasan R&D Campus, 51, Gasan Digital 1-ro, Geumcheon-gu, Seoul, 08592, South Korea
| | - Yuya Sato
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, 395-8569, Japan
| | - Atsushi Ogata
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, 395-8569, Japan
| | - Hiroshi Habe
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, 395-8569, Japan
| | - Tomoyuki Hori
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, 395-8569, Japan.
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Igarashi K, Miyako E, Kato S. Direct Interspecies Electron Transfer Mediated by Graphene Oxide-Based Materials. Front Microbiol 2020; 10:3068. [PMID: 32010112 PMCID: PMC6978667 DOI: 10.3389/fmicb.2019.03068] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 12/19/2019] [Indexed: 11/30/2022] Open
Abstract
Conductive materials are known to promote direct interspecies electron transfer (DIET) by electrically bridging microbial cells. Previous studies have suggested that supplementation of graphene oxide (GO) based materials, including GO, and reduced GO (rGO), to anaerobic microbial communities, can promote DIET. This promotion mechanism is thought to be involved in electron transfer via rGO or biologically formed rGO. However, concrete evidence that rGO directly promotes DIET is still lacking. Furthermore, the effects of the physicochemical properties of GO-based materials on DIET efficiency have not been elucidated. In the current work, we investigated whether chemically and biologically reduced GO compounds can promote DIET in a defined model coculture system, and also examined the effects of surface properties on DIET-promoting efficiency. Supplementation of GO to a defined DIET coculture composed of an ethanol-oxidizing electron producer Geobacter metallireducens and a methane-producing electron consumer Methanosarcina barkeri promoted methane production from ethanol. X-ray photoelectron spectroscopy revealed that GO was reduced to rGO during cultivation by G. metallireducens activity. The stoichiometry of methane production from ethanol and the isotope labeling experiments clearly showed that biologically reduced GO induced DIET-mediated syntrophic methanogenesis. We also assessed the DIET-promoting efficiency of chemically reduced GO and its derivatives, including hydrophilic amine-functionalized rGO (rGO-NH2) and hydrophobic octadecylamine-functionalized rGO (rGO-ODA). While all tested rGO derivatives induced DIET, the rGO derivatives with higher hydrophilicity showed higher DIET-promoting efficiency. Optical microscope observation revealed that microbial cells, in particular, G. metallireducens, more quickly adhered to more hydrophilic GO-based materials. The superior ability to recruit microbial cells is a critical feature of the higher DIET-promoting efficiency of the hydrophilic materials. This study demonstrates that biologically and chemically reduced GO can promote DIET-mediated syntrophic methanogenesis. Our results also suggested that the surface hydrophilicity (i.e., affinity toward microbial cells) is one of the important determinants of the DIET-promoting efficiencies. These observations will provide useful guidance for the selection of conductive particles for the improvement of methanogenesis in anaerobic digesters.
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Affiliation(s)
- Kensuke Igarashi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Sapporo, Japan
| | - Eijiro Miyako
- Nanomaterials Research Institute, AIST, Tsukuba, Japan
| | - Souichiro Kato
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Sapporo, Japan.,Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
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Fischer MA, Ulbricht A, Neulinger SC, Refai S, Waßmann K, Künzel S, Schmitz RA. Immediate Effects of Ammonia Shock on Transcription and Composition of a Biogas Reactor Microbiome. Front Microbiol 2019; 10:2064. [PMID: 31555248 PMCID: PMC6742706 DOI: 10.3389/fmicb.2019.02064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 08/21/2019] [Indexed: 12/22/2022] Open
Abstract
The biotechnological process of biogas production from organic material is carried out by a diverse microbial community under anaerobic conditions. However, the complex and sensitive microbial network present in anaerobic degradation of organic material can be disturbed by increased ammonia concentration introduced into the system by protein-rich substrates and imbalanced feeding. Here, we report on a simulated increase of ammonia concentration in a fed batch lab-scale biogas reactor experiment. Two treatment conditions were used simulating total ammonia nitrogen concentrations of 4.9 and 8.0 g/L with four replicate reactors. Each reactor was monitored concerning methane generation and microbial composition using 16S rRNA gene amplicon sequencing, while the transcriptional activity of the overall process was investigated by metatranscriptomic analysis. This allowed investigating the response of the microbial community in terms of species composition and transcriptional activity to a rapid upshift to high ammonia conditions. Clostridia and Methanomicrobiales dominated the microbial community throughout the entire experiment under both experimental conditions, while Methanosarcinales were only present in minor abundance. Transcription analysis demonstrated clostridial dominance with respect to genes encoding for enzymes of the hydrolysis step (cellulase, EC 3.2.1.4) as well as dominance of key genes for enzymes of the methanogenic pathway (methyl-CoM reductase, EC 2.8.4.1; heterodisulfide reductase, EC 1.8.98.1). Upon ammonia shock, the selected marker genes showed significant changes in transcriptional activity. Cellulose hydrolysis as well as methanogenesis were significantly reduced at high ammonia concentrations as indicated by reduced transcription levels of the corresponding genes. Based on these experiments we concluded that, apart from the methanogenic archaea, hydrolytic cellulose-degrading microorganisms are negatively affected by high ammonia concentrations. Further, Acholeplasma and Erysipelotrichia showed lower abundance under increased ammonia concentrations and thus might serve as indicator species for an earlier detection in order to counteract against ammonia crises.
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Affiliation(s)
- Martin A Fischer
- Department of Biology, Institute of General Microbiology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Andrea Ulbricht
- Department of Biology, Institute of General Microbiology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Sven C Neulinger
- Department of Biology, Institute of General Microbiology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Sarah Refai
- Department of Biology, Institut für Mikrobiologie und Biotechnologie, University Bonn, Bonn, Germany
| | - Kati Waßmann
- Department of Biology, Institut für Mikrobiologie und Biotechnologie, University Bonn, Bonn, Germany
| | - Sven Künzel
- Department for Evolutionary Genetics, Max-Planck-Institute for Evolutionary Biology, Plön, Germany
| | - Ruth A Schmitz
- Department of Biology, Institute of General Microbiology, Christian-Albrechts-University Kiel, Kiel, Germany
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11
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Singh A, Müller B, Fuxelius HH, Schnürer A. AcetoBase: a functional gene repository and database for formyltetrahydrofolate synthetase sequences. Database (Oxford) 2019; 2019:baz142. [PMID: 31832668 PMCID: PMC6908459 DOI: 10.1093/database/baz142] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/01/2019] [Accepted: 11/14/2019] [Indexed: 01/01/2023]
Abstract
Acetogenic bacteria are imperative to environmental carbon cycling and diverse biotechnological applications, but their extensive physiological and taxonomical diversity is an impediment to systematic taxonomic studies. Acetogens are chemolithoautotrophic bacteria that perform reductive carbon fixation under anaerobic conditions through the Wood-Ljungdahl pathway (WLP)/acetyl-coenzyme A pathway. The gene-encoding formyltetrahydrofolate synthetase (FTHFS), a key enzyme of this pathway, is highly conserved and can be used as a molecular marker to probe acetogenic communities. However, there is a lack of systematic collection of FTHFS sequence data at nucleotide and protein levels. In an attempt to streamline investigations on acetogens, we developed AcetoBase - a repository and database for systematically collecting and organizing information related to FTHFS sequences. AcetoBase also provides an opportunity to submit data and obtain accession numbers, perform homology searches for sequence identification and access a customized blast database of submitted sequences. AcetoBase provides the prospect to identify potential acetogenic bacteria, based on metadata information related to genome content and the WLP, supplemented with FTHFS sequence accessions, and can be an important tool in the study of acetogenic communities. AcetoBase can be publicly accessed at https://acetobase.molbio.slu.se.
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Affiliation(s)
- Abhijeet Singh
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala BioCenter, Box 7025, SE-750 07 Uppsala, Sweden
| | - Bettina Müller
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala BioCenter, Box 7025, SE-750 07 Uppsala, Sweden
| | - Hans-Henrik Fuxelius
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala BioCenter, Box 7025, SE-750 07 Uppsala, Sweden
| | - Anna Schnürer
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala BioCenter, Box 7025, SE-750 07 Uppsala, Sweden
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12
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Lv Z, Leite AF, Harms H, Glaser K, Liebetrau J, Kleinsteuber S, Nikolausz M. Microbial community shifts in biogas reactors upon complete or partial ammonia inhibition. Appl Microbiol Biotechnol 2018; 103:519-533. [DOI: 10.1007/s00253-018-9444-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/17/2018] [Accepted: 10/08/2018] [Indexed: 10/28/2022]
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13
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Peng J, Wegner CE, Bei Q, Liu P, Liesack W. Metatranscriptomics reveals a differential temperature effect on the structural and functional organization of the anaerobic food web in rice field soil. MICROBIOME 2018; 6:169. [PMID: 30231929 PMCID: PMC6147125 DOI: 10.1186/s40168-018-0546-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 08/31/2018] [Indexed: 05/22/2023]
Abstract
BACKGROUND The expected increase in global surface temperature due to climate change may have a tremendous effect on the structure and function of the anaerobic food web in flooded rice field soil. Here, we used the metatranscriptomic analysis of total RNA to gain a system-level understanding of this temperature effect on the methanogenic food web. RESULTS Mesophilic (30 °C) and thermophilic (45 °C) food web communities had a modular structure. Family-specific rRNA dynamics indicated that each network module represents a particular function within the food webs. Temperature had a differential effect on all the functional activities, including polymer hydrolysis, syntrophic oxidation of key intermediates, and methanogenesis. This was further evidenced by the temporal expression patterns of total bacterial and archaeal mRNA and of transcripts encoding carbohydrate-active enzymes (CAZymes). At 30 °C, various bacterial phyla contributed to polymer hydrolysis, with Firmicutes decreasing and non-Firmicutes (e.g., Bacteroidetes, Ignavibacteriae) increasing with incubation time. At 45 °C, CAZyme expression was solely dominated by the Firmicutes but, depending on polymer and incubation time, varied on family level. The structural and functional community dynamics corresponded well to process measurements (acetate, propionate, methane). At both temperatures, a major change in food web functionality was linked to the transition from the early to late stage. The mesophilic food web was characterized by gradual polymer breakdown that governed acetoclastic methanogenesis (Methanosarcinaceae) and, with polymer hydrolysis becoming the rate-limiting step, syntrophic propionate oxidation (Christensenellaceae, Peptococcaceae). The thermophilic food web had two activity stages characterized first by polymer hydrolysis and followed by syntrophic oxidation of acetate (Thermoanaerobacteraceae, Heliobacteriaceae, clade OPB54). Hydrogenotrophic Methanocellaceae were the syntrophic methanogen partner, but their population structure differed between the temperatures. Thermophilic temperature promoted proliferation of a new Methanocella ecotype. CONCLUSIONS Temperature had a differential effect on the structural and functional continuum in which the methanogenic food web operates. This temperature-induced change in food web functionality may not only be a near-future scenario for rice paddies but also for natural wetlands in the tropics and subtropics.
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Affiliation(s)
- Jingjing Peng
- Research Group Methanotrophic Bacteria and Environmental Genomics/Transcriptomics, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043, Marburg, Germany
| | - Carl-Eric Wegner
- Institute of Ecology, Aquatic Geomicrobiology, Friedrich Schiller University Jena, Dornburger Str. 159, 07749, Jena, Germany
| | - Qicheng Bei
- Research Group Methanotrophic Bacteria and Environmental Genomics/Transcriptomics, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043, Marburg, Germany
| | - Pengfei Liu
- Research Group Methanotrophic Bacteria and Environmental Genomics/Transcriptomics, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043, Marburg, Germany
| | - Werner Liesack
- Research Group Methanotrophic Bacteria and Environmental Genomics/Transcriptomics, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043, Marburg, Germany.
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14
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Liang X, Whitham JM, Holwerda EK, Shao X, Tian L, Wu YW, Lombard V, Henrissat B, Klingeman DM, Yang ZK, Podar M, Richard TL, Elkins JG, Brown SD, Lynd LR. Development and characterization of stable anaerobic thermophilic methanogenic microbiomes fermenting switchgrass at decreasing residence times. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:243. [PMID: 30202438 PMCID: PMC6126044 DOI: 10.1186/s13068-018-1238-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 08/27/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Anaerobic fermentation of lignocellulose occurs in both natural and managed environments, and is an essential part of the carbon cycle as well as a promising route to sustainable production of fuels and chemicals. Lignocellulose solubilization by mixed microbiomes is important in these contexts. RESULTS Here, we report the development of stable switchgrass-fermenting enrichment cultures maintained at various residence times and moderately high (55 °C) temperatures. Anaerobic microbiomes derived from a digester inoculum were incubated at 55 °C and fed semi-continuously with medium containing 30 g/L mid-season harvested switchgrass to achieve residence times (RT) of 20, 10, 5, and 3.3 days. Stable, time-invariant cellulolytic methanogenic cultures with minimal accumulation of organic acids were achieved for all RTs. Fractional carbohydrate solubilization was 0.711, 0.654, 0.581 and 0.538 at RT = 20, 10, 5 and 3.3 days, respectively, and glucan solubilization was proportional to xylan solubilization at all RTs. The rate of solubilization was described well by the equation r = k(C - C0fr), where C represents the concentration of unutilized carbohydrate, C0 is the concentration of carbohydrate (cellulose and hemicellulose) entering the bioreactor and fr is the extrapolated fraction of entering carbohydrate that is recalcitrant at infinite residence time. The 3.3 day RT is among the shortest RT reported for stable thermophilic, methanogenic digestion of a lignocellulosic feedstock. 16S rDNA phylotyping and metagenomic analyses were conducted to characterize the effect of RT on community dynamics and to infer functional roles in the switchgrass to biogas conversion to the various microbial taxa. Firmicutes were the dominant phylum, increasing in relative abundance from 54 to 96% as RT decreased. A Clostridium clariflavum strain with genetic markers for xylose metabolism was the most abundant lignocellulose-solubilizing bacterium. A Thermotogae (Defluviitoga tunisiensis) was the most abundant bacterium in switchgrass digesters at RT = 20 days but decreased in abundance at lower RTs as did multiple Chloroflexi. Synergistetes and Euryarchaeota were present at roughly constant levels over the range of RTs examined. CONCLUSIONS A system was developed in which stable methanogenic steady-states were readily obtained with a particulate biomass feedstock, mid-season switchgrass, at laboratory (1 L) scale. Characterization of the extent and rate of carbohydrate solubilization in combination with 16S rDNA and metagenomic sequencing provides a multi-dimensional view of performance, species composition, glycoside hydrolases, and metabolic function with varying residence time. These results provide a point of reference and guidance for future studies and organism development efforts involving defined cultures.
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Affiliation(s)
- Xiaoyu Liang
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
- BioEnergy Sciences Center, Oak Ridge, TN 37830 USA
| | - Jason M. Whitham
- BioEnergy Sciences Center, Oak Ridge, TN 37830 USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - Evert K. Holwerda
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
- BioEnergy Sciences Center, Oak Ridge, TN 37830 USA
| | - Xiongjun Shao
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
- BioEnergy Sciences Center, Oak Ridge, TN 37830 USA
| | - Liang Tian
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
- BioEnergy Sciences Center, Oak Ridge, TN 37830 USA
| | - Yu-Wei Wu
- Graduate Institute of Biomedical Informatics, College of Medical Science and Technology, Taipei Medical University, Taipei, 106 Taiwan
| | - Vincent Lombard
- CNRS, UMR 7257, Aix-Marseille University, 13288 Marseille, France
- INRA, USC 1408 AFMB, 13288 Marseille, France
| | - Bernard Henrissat
- CNRS, UMR 7257, Aix-Marseille University, 13288 Marseille, France
- INRA, USC 1408 AFMB, 13288 Marseille, France
- Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Dawn M. Klingeman
- BioEnergy Sciences Center, Oak Ridge, TN 37830 USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - Zamin K. Yang
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - Mircea Podar
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - Tom L. Richard
- Department of Agricultural and Biological Engineering, The Pennsylvania State University, University Park, State College, PA 16802 USA
| | - James G. Elkins
- BioEnergy Sciences Center, Oak Ridge, TN 37830 USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - Steven D. Brown
- BioEnergy Sciences Center, Oak Ridge, TN 37830 USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
- Present Address: LanzaTech, Inc., Skokie, IL 60077 USA
| | - Lee R. Lynd
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
- BioEnergy Sciences Center, Oak Ridge, TN 37830 USA
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15
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New concepts in anaerobic digestion processes: recent advances and biological aspects. Appl Microbiol Biotechnol 2018; 102:5065-5076. [DOI: 10.1007/s00253-018-9039-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/16/2018] [Accepted: 04/16/2018] [Indexed: 10/17/2022]
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16
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Wang HZ, Gou M, Yi Y, Xia ZY, Tang YQ. Identification of novel potential acetate-oxidizing bacteria in an acetate-fed methanogenic chemostat based on DNA stable isotope probing. J GEN APPL MICROBIOL 2018; 64:221-231. [DOI: 10.2323/jgam.2017.12.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Hui-Zhong Wang
- College of Architecture and Environment, Sichuan University
| | - Min Gou
- College of Architecture and Environment, Sichuan University
| | - Yue Yi
- College of Architecture and Environment, Sichuan University
| | - Zi-Yuan Xia
- College of Architecture and Environment, Sichuan University
| | - Yue-Qin Tang
- College of Architecture and Environment, Sichuan University
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17
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Mulat DG, Huerta SG, Kalyani D, Horn SJ. Enhancing methane production from lignocellulosic biomass by combined steam-explosion pretreatment and bioaugmentation with cellulolytic bacterium Caldicellulosiruptor bescii. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:19. [PMID: 29422947 PMCID: PMC5787918 DOI: 10.1186/s13068-018-1025-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 01/13/2018] [Indexed: 05/07/2023]
Abstract
BACKGROUND Biogas production from lignocellulosic biomass is generally considered to be challenging due to the recalcitrant nature of this biomass. In this study, the recalcitrance of birch was reduced by applying steam-explosion (SE) pretreatment (210 °C and 10 min). Moreover, bioaugmentation with the cellulolytic bacterium Caldicellulosiruptor bescii was applied to possibly enhance the methane production from steam-exploded birch in an anaerobic digestion (AD) process under thermophilic conditions (62 °C). RESULTS Overall, the combined SE and bioaugmentation enhanced the methane yield up to 140% compared to untreated birch, while SE alone contributed to the major share of methane enhancement by 118%. The best methane improvement of 140% on day 50 was observed in bottles fed with pretreated birch and bioaugmentation with lower dosages of C. bescii (2 and 5% of inoculum volume). The maximum methane production rate also increased from 4-mL CH4/g VS (volatile solids)/day for untreated birch to 9-14-mL CH4/g VS/day for steam-exploded birch with applied bioaugmentation. Bioaugmentation was particularly effective for increasing the initial methane production rate of the pretreated birch yielding 21-44% more methane than the pretreated birch without applied bioaugmentation. The extent of solubilization of the organic matter was increased by more than twofold when combined SE pretreatment and bioaugmentation was used in comparison with the methane production from untreated birch. The beneficial effects of SE and bioaugmentation on methane yield indicated that biomass recalcitrance and hydrolysis step are the limiting factors for efficient AD of lignocellulosic biomass. Microbial community analysis by 16S rRNA amplicon sequencing showed that the microbial community composition was altered by the pretreatment and bioaugmentation processes. Notably, the enhanced methane production by pretreatment and bioaugmentation was well correlated with the increase in abundance of key bacterial and archaeal communities, particularly the hydrolytic bacterium Caldicoprobacter, several members of syntrophic acetate oxidizing bacteria and the hydrogenotrophic Methanothermobacter. CONCLUSION Our findings demonstrate the potential of combined SE and bioaugmentation for enhancing methane production from lignocellulosic biomass.
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Affiliation(s)
- Daniel Girma Mulat
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O.Box 5003, 1432 Ås, Norway
| | - Silvia Greses Huerta
- Department of Chemical Engineering, University of Valencia, P.O.Box 46100, Valencia, Spain
| | - Dayanand Kalyani
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O.Box 5003, 1432 Ås, Norway
| | - Svein Jarle Horn
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O.Box 5003, 1432 Ås, Norway
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18
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The microbiome as engineering tool: Manufacturing and trading between microorganisms. N Biotechnol 2017; 39:206-214. [DOI: 10.1016/j.nbt.2017.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 04/21/2017] [Accepted: 07/01/2017] [Indexed: 11/24/2022]
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19
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Szeinbaum N, Lin H, Brandes JA, Taillefert M, Glass JB, DiChristina TJ. Microbial manganese(III) reduction fuelled by anaerobic acetate oxidation. Environ Microbiol 2017. [PMID: 28631370 DOI: 10.1111/1462-2920.13829] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Soluble manganese in the intermediate +III oxidation state (Mn3+ ) is a newly identified oxidant in anoxic environments, whereas acetate is a naturally abundant substrate that fuels microbial activity. Microbial populations coupling anaerobic acetate oxidation to Mn3+ reduction, however, have yet to be identified. We isolated a Shewanella strain capable of oxidizing acetate anaerobically with Mn3+ as the electron acceptor, and confirmed this phenotype in other strains. This metabolic connection between acetate and soluble Mn3+ represents a new biogeochemical link between carbon and manganese cycles. Genomic analyses uncovered four distinct genes that allow for pathway variations in the complete dehydrogenase-driven TCA cycle that could support anaerobic acetate oxidation coupled to metal reduction in Shewanella and other Gammaproteobacteria. An oxygen-tolerant TCA cycle supporting anaerobic manganese reduction is thus a new connection in the manganese-driven carbon cycle, and a new variable for models that use manganese as a proxy to infer oxygenation events on early Earth.
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Affiliation(s)
- Nadia Szeinbaum
- School of Biology, Georgia Institute of Technology, Atlanta, GA, USA
| | - Hui Lin
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Jay A Brandes
- Skidaway Institute of Oceanography, Savannah, GA, USA
| | - Martial Taillefert
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Jennifer B Glass
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
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20
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Kouzuma A, Tsutsumi M, Ishii S, Ueno Y, Abe T, Watanabe K. Non-autotrophic methanogens dominate in anaerobic digesters. Sci Rep 2017; 7:1510. [PMID: 28473726 PMCID: PMC5431450 DOI: 10.1038/s41598-017-01752-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 04/03/2017] [Indexed: 12/12/2022] Open
Abstract
Anaerobic digesters are man-made habitats for fermentative and methanogenic microbes, and are characterized by extremely high concentrations of organics. However, little is known about how microbes adapt to such habitats. In the present study, we report phylogenetic, metagenomic, and metatranscriptomic analyses of microbiomes in thermophilic packed-bed digesters fed acetate as the major substrate, and we have shown that acetoclastic and hydrogenotrophic methanogens that utilize acetate as a carbon source dominate there. Deep sequencing and precise binning of the metagenomes reconstructed complete genomes for two dominant methanogens affiliated with the genera Methanosarcina and Methanothermobacter, along with 37 draft genomes. The reconstructed Methanosarcina genome was almost identical to that of a thermophilic acetoclastic methanogen Methanosarcina thermophila TM-1, indicating its cosmopolitan distribution in thermophilic digesters. The reconstructed Methanothermobacter (designated as Met2) was closely related to Methanothermobacter tenebrarum, a non-autotrophic hydrogenotrophic methanogen that grows in the presence of acetate. Met2 lacks the Cdh complex required for CO2 fixation, suggesting that it requires organic molecules, such as acetate, as carbon sources. Although the metagenomic analysis also detected autotrophic methanogens, they were less than 1% in abundance of Met2. These results suggested that non-autotrophic methanogens preferentially grow in anaerobic digesters containing high concentrations of organics.
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Affiliation(s)
- Atsushi Kouzuma
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan.
| | - Maho Tsutsumi
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan
| | - Shun'ichi Ishii
- R&D Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Nankoku, Kochi, 783-8502, Japan
| | - Yoshiyuki Ueno
- Kajima Technical Research Institute, Chofu, Tokyo, 182-0036, Japan
| | - Takashi Abe
- Graduate School of Science and Technology, Niigata University, Niigata, Niigata, 950-2181, Japan
| | - Kazuya Watanabe
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan
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21
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Kougias PG, Treu L, Benavente DP, Boe K, Campanaro S, Angelidaki I. Ex-situ biogas upgrading and enhancement in different reactor systems. BIORESOURCE TECHNOLOGY 2017; 225:429-437. [PMID: 27931939 DOI: 10.1016/j.biortech.2016.11.124] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/28/2016] [Accepted: 11/30/2016] [Indexed: 05/24/2023]
Abstract
Biogas upgrading is envisioned as a key process for clean energy production. The current study evaluates the efficiency of different reactor configurations for ex-situ biogas upgrading and enhancement, in which externally provided hydrogen and carbon dioxide were biologically converted to methane by the action of hydrogenotrophic methanogens. The methane content in the output gas of the most efficient configuration was >98%, allowing its exploitation as substitute to natural gas. Additionally, use of digestate from biogas plants as a cost efficient method to provide all the necessary nutrients for microbial growth was successful. High-throughput 16S rRNA sequencing revealed that the microbial community was resided by novel phylotypes belonging to the uncultured order MBA08 and to Bacteroidales. Moreover, only hydrogenotrophic methanogens were identified belonging to Methanothermobacter and Methanoculleus genera. Methanothermobacter thermautotrophicus was the predominant methanogen in the biofilm formed on top of the diffuser surface in the bubble column reactor.
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Affiliation(s)
- Panagiotis G Kougias
- Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark.
| | - Laura Treu
- Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark; Department of Agronomy, Food, Natural Resources, Animal and Environment (DAFNAE), Viale dell'Università, 16, 35020 Legnaro (Padova), Italy
| | | | - Kanokwan Boe
- Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Stefano Campanaro
- Department of Biology, University of Padua, Via U. Bassi 58/b, 35121 Padova, Italy
| | - Irini Angelidaki
- Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
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22
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Manzoor S, Bongcam-Rudloff E, Schnürer A, Müller B. Genome-Guided Analysis and Whole Transcriptome Profiling of the Mesophilic Syntrophic Acetate Oxidising Bacterium Syntrophaceticus schinkii. PLoS One 2016; 11:e0166520. [PMID: 27851830 PMCID: PMC5113046 DOI: 10.1371/journal.pone.0166520] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 10/31/2016] [Indexed: 01/29/2023] Open
Abstract
Syntrophaceticus schinkii is a mesophilic, anaerobic bacterium capable of oxidising acetate to CO2 and H2 in intimate association with a methanogenic partner, a syntrophic relationship which operates close to the energetic limits of microbial life. Syntrophaceticus schinkii has been identified as a key organism in engineered methane-producing processes relying on syntrophic acetate oxidation as the main methane-producing pathway. However, due to strict cultivation requirements and difficulties in reconstituting the thermodynamically unfavourable acetate oxidation, the physiology of this functional group is poorly understood. Genome-guided and whole transcriptome analyses performed in the present study provide new insights into habitat adaptation, syntrophic acetate oxidation and energy conservation. The working draft genome of Syntrophaceticus schinkii indicates limited metabolic capacities, with lack of organic nutrient uptake systems, chemotactic machineries, carbon catabolite repression and incomplete biosynthesis pathways. Ech hydrogenase, [FeFe] hydrogenases, [NiFe] hydrogenases, F1F0-ATP synthase and membrane-bound and cytoplasmic formate dehydrogenases were found clearly expressed, whereas Rnf and a predicted oxidoreductase/heterodisulphide reductase complex, both found encoded in the genome, were not expressed under syntrophic growth condition. A transporter sharing similarities to the high-affinity acetate transporters of aceticlastic methanogens was also found expressed, suggesting that Syntrophaceticus schinkii can potentially compete with methanogens for acetate. Acetate oxidation seems to proceed via the Wood-Ljungdahl pathway as all genes involved in this pathway were highly expressed. This study shows that Syntrophaceticus schinkii is a highly specialised, habitat-adapted organism relying on syntrophic acetate oxidation rather than metabolic versatility. By expanding its complement of respiratory complexes, it might overcome limiting bioenergetic barriers, and drive efficient energy conservation from reactions operating close to the thermodynamic equilibrium, which might enable S. schinkii to occupy the same niche as the aceticlastic methanogens. The knowledge gained here will help specify process conditions supporting efficient and robust biogas production and will help identify mechanisms important for the syntrophic lifestyle.
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Affiliation(s)
- Shahid Manzoor
- Department of Information Technology, University of the Punjab, Lahore, Pakistan
| | - Erik Bongcam-Rudloff
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Science, SLU-Global Bioinformatics Centre, Uppsala, SE 750 07, Sweden
| | - Anna Schnürer
- Department of Microbiology, Swedish University of Agricultural Sciences, BioCenter, Uppsala, SE 750 07, Sweden
| | - Bettina Müller
- Department of Microbiology, Swedish University of Agricultural Sciences, BioCenter, Uppsala, SE 750 07, Sweden
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Mosbæk F, Kjeldal H, Mulat DG, Albertsen M, Ward AJ, Feilberg A, Nielsen JL. Identification of syntrophic acetate-oxidizing bacteria in anaerobic digesters by combined protein-based stable isotope probing and metagenomics. THE ISME JOURNAL 2016; 10:2405-18. [PMID: 27128991 PMCID: PMC5030692 DOI: 10.1038/ismej.2016.39] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 01/22/2016] [Accepted: 02/02/2016] [Indexed: 12/31/2022]
Abstract
Inhibition of anaerobic digestion through accumulation of volatile fatty acids occasionally occurs as the result of unbalanced growth between acidogenic bacteria and methanogens. A fast recovery is a prerequisite for establishing an economical production of biogas. However, very little is known about the microorganisms facilitating this recovery. In this study, we investigated the organisms involved by a novel approach of mapping protein-stable isotope probing (protein-SIP) onto a binned metagenome. Under simulation of acetate accumulation conditions, formations of (13)C-labeled CO2 and CH4 were detected immediately following incubation with [U-(13)C]acetate, indicating high turnover rate of acetate. The identified (13)C-labeled peptides were mapped onto a binned metagenome for improved identification of the organisms involved. The results revealed that Methanosarcina and Methanoculleus were actively involved in acetate turnover, as were five subspecies of Clostridia. The acetate-consuming organisms affiliating with Clostridia all contained the FTFHS gene for formyltetrahydrofolate synthetase, a key enzyme for reductive acetogenesis, indicating that these organisms are possible syntrophic acetate-oxidizing (SAO) bacteria that can facilitate acetate consumption via SAO, coupled with hydrogenotrophic methanogenesis (SAO-HM). This study represents the first study applying protein-SIP for analysis of complex biogas samples, a promising method for identifying key microorganisms utilizing specific pathways.
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Affiliation(s)
- Freya Mosbæk
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Henrik Kjeldal
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Daniel G Mulat
- Department of Engineering, Aarhus University, Aarhus, Denmark
| | - Mads Albertsen
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Alastair J Ward
- Department of Engineering, Aarhus University, Aarhus, Denmark
| | - Anders Feilberg
- Department of Engineering, Aarhus University, Aarhus, Denmark
| | - Jeppe L Nielsen
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
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Gehring T, Niedermayr A, Berzio S, Immenhauser A, Wichern M, Lübken M. Determination of the fractions of syntrophically oxidized acetate in a mesophilic methanogenic reactor through an (12)C and (13)C isotope-based kinetic model. WATER RESEARCH 2016; 102:362-373. [PMID: 27390036 DOI: 10.1016/j.watres.2016.06.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 06/15/2016] [Accepted: 06/16/2016] [Indexed: 06/06/2023]
Abstract
In order to accurately describe the carbon flow in anaerobic digestion processes, this work investigates the acetate degradation pathways through the use of stable carbon isotope analysis and a mathematical model. Batch assays using labeled (13)C acetate were employed to distinguish the acetate consumption through methanogenic Archaea and acetate-oxidizing Bacteria. Suspended and sessile biomass, with over 400 days of retention time, from a mesophilic (36.5 °C) upflow anaerobic filter was used as inocula in these assays. A three-process model for acetoclastic methanogenesis and syntrophic acetate oxidation (SAO) was developed to allow for a precise quantification of the SAO contribution. The model distinguishes carbon atoms in light and heavy isotopes, (12)C and (13)C, respectively, which permitted the simulation of the isotope ratios variation in addition to gas production, gas composition and acetate concentrations. The model indicated oxidized fractions of acetate between 7 and 18%. Due to the low free ammonia inhibition potential for the acetoclastic methanogens in these assays these findings point to the biomass retention times as a driven factor for the SAO pathway. The isotope-based kinetic model developed here also describes the δ(13)C variations in unlabeled assays accurately and has the potential to determine biological (13)C fractionation factors.
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Affiliation(s)
- Tito Gehring
- Institute of Urban Water Management and Environmental Engineering, Ruhr-Universität Bochum, Germany.
| | - Andrea Niedermayr
- Institute of Geology, Mineralogy and Geophysics, Ruhr-Universität Bochum, Germany.
| | - Stephan Berzio
- Institute of Urban Water Management and Environmental Engineering, Ruhr-Universität Bochum, Germany.
| | - Adrian Immenhauser
- Institute of Geology, Mineralogy and Geophysics, Ruhr-Universität Bochum, Germany.
| | - Marc Wichern
- Institute of Urban Water Management and Environmental Engineering, Ruhr-Universität Bochum, Germany.
| | - Manfred Lübken
- Institute of Urban Water Management and Environmental Engineering, Ruhr-Universität Bochum, Germany.
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Novel Syntrophic Populations Dominate an Ammonia-Tolerant Methanogenic Microbiome. mSystems 2016; 1:mSystems00092-16. [PMID: 27822555 PMCID: PMC5080403 DOI: 10.1128/msystems.00092-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 08/18/2016] [Indexed: 12/31/2022] Open
Abstract
The microbial production of methane or “biogas” is an attractive renewable energy technology that can recycle organic waste into biofuel. Biogas reactors operating with protein-rich substrates such as household municipal or agricultural wastes have significant industrial and societal value; however, they are highly unstable and frequently collapse due to the accumulation of ammonia. We report the discovery of a novel uncultured phylotype (unFirm_1) that is highly detectable in metaproteomic data generated from an ammonia-tolerant commercial reactor. Importantly, unFirm_1 is proposed to perform a key metabolic step in biogas microbiomes, whereby it syntrophically oxidizes acetate to hydrogen and carbon dioxide, which methanogens then covert to methane. Only very few culturable syntrophic acetate-oxidizing bacteria have been described, and all were detected at low in situ levels compared to unFirm_1. Broader comparisons produced the hypothesis that unFirm_1 is a key mediator toward the successful long-term stable operation of biogas production using protein-rich substrates. Biogas reactors operating with protein-rich substrates have high methane potential and industrial value; however, they are highly susceptible to process failure because of the accumulation of ammonia. High ammonia levels cause a decline in acetate-utilizing methanogens and instead promote the conversion of acetate via a two-step mechanism involving syntrophic acetate oxidation (SAO) to H2 and CO2, followed by hydrogenotrophic methanogenesis. Despite the key role of syntrophic acetate-oxidizing bacteria (SAOB), only a few culturable representatives have been characterized. Here we show that the microbiome of a commercial, ammonia-tolerant biogas reactor harbors a deeply branched, uncultured phylotype (unFirm_1) accounting for approximately 5% of the 16S rRNA gene inventory and sharing 88% 16S rRNA gene identity with its closest characterized relative. Reconstructed genome and quantitative metaproteomic analyses imply unFirm_1’s metabolic dominance and SAO capabilities, whereby the key enzymes required for acetate oxidation are among the most highly detected in the reactor microbiome. While culturable SAOB were identified in genomic analyses of the reactor, their limited proteomic representation suggests that unFirm_1 plays an important role in channeling acetate toward methane. Notably, unFirm_1-like populations were found in other high-ammonia biogas installations, conjecturing a broader importance for this novel clade of SAOB in anaerobic fermentations. IMPORTANCE The microbial production of methane or “biogas” is an attractive renewable energy technology that can recycle organic waste into biofuel. Biogas reactors operating with protein-rich substrates such as household municipal or agricultural wastes have significant industrial and societal value; however, they are highly unstable and frequently collapse due to the accumulation of ammonia. We report the discovery of a novel uncultured phylotype (unFirm_1) that is highly detectable in metaproteomic data generated from an ammonia-tolerant commercial reactor. Importantly, unFirm_1 is proposed to perform a key metabolic step in biogas microbiomes, whereby it syntrophically oxidizes acetate to hydrogen and carbon dioxide, which methanogens then covert to methane. Only very few culturable syntrophic acetate-oxidizing bacteria have been described, and all were detected at low in situ levels compared to unFirm_1. Broader comparisons produced the hypothesis that unFirm_1 is a key mediator toward the successful long-term stable operation of biogas production using protein-rich substrates.
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Li Z, Henderson G, Yang Y, Li G. Diversity of formyltetrahydrofolate synthetase genes in the rumens of roe deer (Capreolus pygargus) and sika deer (Cervus nippon) fed different diets. Can J Microbiol 2016; 63:11-19. [PMID: 27819479 DOI: 10.1139/cjm-2016-0424] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reductive acetogenesis by homoacetogens represents an alternative pathway to methanogenesis to remove metabolic hydrogen during rumen fermentation. In this study, we investigated the occurrence of homoacetogen in the rumens of pasture-fed roe deer (Capreolus pygargus) and sika deer (Cervus nippon) fed either oak-leaf-based (tannin-rich, 100 mg/kg dried matter), corn-stover-based, or corn-silage-based diets, by using formyltetrahydrofolate synthetase (FTHFS) gene sequences as a marker. The diversity and richness of FTHFS sequences was lowest in animals fed oak leaf, indicating that tannin-containing plants may affect rumen homoacetogen diversity. FTHFS amino acid sequences in the rumen of roe deer significantly differed from those of sika deer. The phylogenetic analyses showed that 44.8% of sequences in pasture-fed roe deer, and 72.1%, 81.1%, and 37.5% of sequences in sika deer fed oak-leaf-, corn-stover-, and corn-silage-based diets, respectively, may represent novel bacteria that have not yet been cultured. These results demonstrate that the rumens of roe deer and sika deer harbor potentially novel homoacetogens and that diet may influence homoacetogen community structure.
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Affiliation(s)
- Zhipeng Li
- a Jilin Provincial Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Animal and Plant Sciences, Chinese Academy of Agricultural Sciences, Changchun, Jilin, People's Republic of China
| | - Gemma Henderson
- b AgResearch, Grasslands Research Centre, Palmerston North 4442, New Zealand
| | - Yahan Yang
- a Jilin Provincial Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Animal and Plant Sciences, Chinese Academy of Agricultural Sciences, Changchun, Jilin, People's Republic of China
| | - Guangyu Li
- a Jilin Provincial Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Animal and Plant Sciences, Chinese Academy of Agricultural Sciences, Changchun, Jilin, People's Republic of China
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De Vrieze J, Verstraete W. Perspectives for microbial community composition in anaerobic digestion: from abundance and activity to connectivity. Environ Microbiol 2016; 18:2797-809. [DOI: 10.1111/1462-2920.13437] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Jo De Vrieze
- Center for Microbial Ecology and Technology (CMET), Ghent University; Coupure Links 653 Gent B-9000 Belgium
| | - Willy Verstraete
- Center for Microbial Ecology and Technology (CMET), Ghent University; Coupure Links 653 Gent B-9000 Belgium
- Avecom NV, Industrieweg 122P; Wondelgem 9032 Belgium
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28
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Müller B, Sun L, Westerholm M, Schnürer A. Bacterial community composition and fhs profiles of low- and high-ammonia biogas digesters reveal novel syntrophic acetate-oxidising bacteria. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:48. [PMID: 26925165 PMCID: PMC4769498 DOI: 10.1186/s13068-016-0454-9] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/08/2016] [Indexed: 05/04/2023]
Abstract
BACKGROUND Syntrophic acetate oxidation (SAO) is the predominant pathway for methane production in high ammonia anaerobic digestion processes. The bacteria (SAOB) occupying this niche and the metabolic pathway are poorly understood. Phylogenetic diversity and strict cultivation requirements hinder comprehensive research and discovery of novel SAOB. Most SAOB characterised to date are affiliated to the physiological group of acetogens. Formyltetrahydrofolate synthetase is a key enzyme of both acetogenic and SAO metabolism. The encoding fhs gene has therefore been identified as a suitable functional marker, using a newly designed primer pair. In this comparative study, we used a combination of terminal restriction fragment length polymorphism profiling, clone-based comparison, qPCR and Illumina amplicon sequencing to assess the bacterial community and acetogenic sub-community prevailing in high- and low-ammonia laboratory-scale digesters in order to delineate potential SAOB communities. Potential candidates identified were further tracked in a number of low-ammonia and high-ammonia laboratory-scale and large-scale digesters in order to reveal a potential function in SAO. RESULTS All methodical approaches revealed significant changes in the bacterial community composition concurrently with increasing ammonia and predominance of SAO. The acetogenic community under high ammonia conditions was revealed to be generally heterogeneous, but formed distinct phylogenetic clusters. The clusters differed clearly from those found under low-ammonia conditions and represented an acetogenic assemblage unique for biogas processes and recurring in a number of high-ammonia processes, indicating potential involvement in SAO. CONCLUSIONS The phylogenetic affiliation and population dynamics observed point to a key community, belonging mainly to the Clostridia class, in particular to the orders Clostridiales and Thermoanaerobacterales, which appear to specialise in SAO rather than being metabolically versatile. Overall, the results reported here provide evidence of functional importance of the bacterial families identified in high-ammonia systems and extend existing knowledge of bacterial and acetogenic assemblages at low and high ammonia levels. This information will be of help in monitoring and assessing the impacts on the SAOB community in order to identify characteristics of robust and productive high ammonia biogas processes.
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Affiliation(s)
- Bettina Müller
- Department of Microbiology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7025, 750 07 Uppsala, Sweden
| | - Li Sun
- Department of Microbiology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7025, 750 07 Uppsala, Sweden
| | - Maria Westerholm
- Department of Microbiology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7025, 750 07 Uppsala, Sweden
| | - Anna Schnürer
- Department of Microbiology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7025, 750 07 Uppsala, Sweden
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Distribution, activities, and interactions of methanogens and sulfate-reducing prokaryotes in the Florida Everglades. Appl Environ Microbiol 2015; 81:7431-42. [PMID: 26276115 DOI: 10.1128/aem.01583-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 08/07/2015] [Indexed: 12/31/2022] Open
Abstract
To gain insight into the mechanisms controlling methanogenic pathways in the Florida Everglades, the distribution and functional activities of methanogens and sulfate-reducing prokaryotes (SRPs) were investigated in soils (0 to 2 or 0 to 4 cm depth) across the well-documented nutrient gradient in the water conservation areas (WCAs) caused by runoff from the adjacent Everglades Agricultural Area. The methyl coenzyme M reductase gene (mcrA) sequences that were retrieved from WCA-2A, an area with relatively high concentrations of SO4 (2-) (≥39 μM), indicated that methanogens inhabiting this area were broadly distributed within the orders Methanomicrobiales, Methanosarcinales, Methanocellales, Methanobacteriales, and Methanomassiliicoccales. In more than 3 years of monitoring, quantitative PCR (qPCR) using newly designed group-specific primers revealed that the hydrogenotrophic Methanomicrobiales were more numerous than the Methanosaetaceae obligatory acetotrophs in SO4 (2-)-rich areas of WCA-2A, while the Methanosaetaceae were dominant over the Methanomicrobiales in WCA-3A (with relatively low SO4 (2-) concentrations; ≤4 μM). qPCR of dsrB sequences also indicated that SRPs are present at greater numbers than methanogens in the WCAs. In an incubation study with WCA-2A soils, addition of MoO4 (2-) (a specific inhibitor of SRP activity) resulted in increased methane production rates, lower apparent fractionation factors [αapp; defined as (amount of δ(13)CO2 + 1,000)/(amount of δ(13)CH4 + 1,000)], and higher Methanosaetaceae mcrA transcript levels compared to those for the controls without MoO4 (2-). These results indicate that SRPs play crucial roles in controlling methanogenic pathways and in shaping the structures of methanogen assemblages as a function of position along the nutrient gradient.
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Hori T, Aoyagi T, Itoh H, Narihiro T, Oikawa A, Suzuki K, Ogata A, Friedrich MW, Conrad R, Kamagata Y. Isolation of microorganisms involved in reduction of crystalline iron(III) oxides in natural environments. Front Microbiol 2015; 6:386. [PMID: 25999927 PMCID: PMC4419728 DOI: 10.3389/fmicb.2015.00386] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 04/15/2015] [Indexed: 11/13/2022] Open
Abstract
Reduction of crystalline Fe(III) oxides is one of the most important electron sinks for organic compound oxidation in natural environments. Yet the limited number of isolates makes it difficult to understand the physiology and ecological impact of the microorganisms involved. Here, two-stage cultivation was implemented to selectively enrich and isolate crystalline iron(III) oxide reducing microorganisms in soils and sediments. Firstly, iron reducers were enriched and other untargeted eutrophs were depleted by 2-years successive culture on a crystalline ferric iron oxide (i.e., goethite, lepidocrocite, hematite, or magnetite) as electron acceptor. Fifty-eight out of 136 incubation conditions allowed the continued existence of microorganisms as confirmed by PCR amplification. High-throughput Illumina sequencing and clone library analysis based on 16S rRNA genes revealed that the enrichment cultures on each of the ferric iron oxides contained bacteria belonging to the Deltaproteobacteria (mainly Geobacteraceae), followed by Firmicutes and Chloroflexi, which also comprised most of the operational taxonomic units (OTUs) identified. Venn diagrams indicated that the core OTUs enriched with all of the iron oxides were dominant in the Geobacteraceae while each type of iron oxides supplemented selectively enriched specific OTUs in the other phylogenetic groups. Secondly, 38 enrichment cultures including novel microorganisms were transferred to soluble-iron(III) containing media in order to stimulate the proliferation of the enriched iron reducers. Through extinction dilution-culture and single colony isolation, six strains within the Deltaproteobacteria were finally obtained; five strains belonged to the genus Geobacter and one strain to Pelobacter. The 16S rRNA genes of these isolates were 94.8-98.1% identical in sequence to cultured relatives. All the isolates were able to grow on acetate and ferric iron but their physiological characteristics differed considerably in terms of growth rate. Thus, the novel strategy allowed to enrich and isolate novel iron(III) reducers that were able to thrive by reducing crystalline ferric iron oxides.
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Affiliation(s)
- Tomoyuki Hori
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology Tsukuba, Japan
| | - Tomo Aoyagi
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology Tsukuba, Japan
| | - Hideomi Itoh
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology Sapporo, Japan
| | - Takashi Narihiro
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology Tsukuba, Japan
| | - Azusa Oikawa
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology Sapporo, Japan
| | - Kiyofumi Suzuki
- Methane Hydrate Research & Development Division, Japan Oil, Gas and Metals National Corporation Chiba, Japan
| | - Atsushi Ogata
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology Tsukuba, Japan
| | - Michael W Friedrich
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry and MARUM, University of Bremen Bremen, Germany
| | - Ralf Conrad
- Max Planck Institute for Terrestrial Microbiology Marburg, Germany
| | - Yoichi Kamagata
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology Tsukuba, Japan
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Hori T, Haruta S, Sasaki D, Hanajima D, Ueno Y, Ogata A, Ishii M, Igarashi Y. Reorganization of the bacterial and archaeal populations associated with organic loading conditions in a thermophilic anaerobic digester. J Biosci Bioeng 2015; 119:337-44. [DOI: 10.1016/j.jbiosc.2014.09.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Revised: 07/28/2014] [Accepted: 09/02/2014] [Indexed: 10/24/2022]
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32
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Kato S, Yoshida R, Yamaguchi T, Sato T, Yumoto I, Kamagata Y. The effects of elevated CO2 concentration on competitive interaction between aceticlastic and syntrophic methanogenesis in a model microbial consortium. Front Microbiol 2014; 5:575. [PMID: 25400628 PMCID: PMC4214200 DOI: 10.3389/fmicb.2014.00575] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 10/13/2014] [Indexed: 11/13/2022] Open
Abstract
Investigation of microbial interspecies interactions is essential for elucidating the function and stability of microbial ecosystems. However, community-based analyses including molecular-fingerprinting methods have limitations for precise understanding of interspecies interactions. Construction of model microbial consortia consisting of defined mixed cultures of isolated microorganisms is an excellent method for research on interspecies interactions. In this study, a model microbial consortium consisting of microorganisms that convert acetate into methane directly (Methanosaeta thermophila) and syntrophically (Thermacetogenium phaeum and Methanothermobacter thermautotrophicus) was constructed and the effects of elevated CO2 concentrations on intermicrobial competition were investigated. Analyses on the community dynamics by quantitative RT-PCR and fluorescent in situ hybridization targeting their 16S rRNAs revealed that high concentrations of CO2 have suppressive effects on the syntrophic microorganisms, but not on the aceticlastic methanogen. The pathways were further characterized by determining the Gibbs free energy changes (ΔG) of the metabolic reactions conducted by each microorganism under different CO2 concentrations. The ΔG value of the acetate oxidation reaction (T. phaeum) under high CO2 conditions became significantly higher than -20 kJ per mol of acetate, which is the borderline level for sustaining microbial growth. These results suggest that high concentrations of CO2 undermine energy acquisition of T. phaeum, resulting in dominance of the aceticlastic methanogen. This study demonstrates that investigation on model microbial consortia is useful for untangling microbial interspecies interactions, including competition among microorganisms occupying the same trophic niche in complex microbial ecosystems.
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Affiliation(s)
- Souichiro Kato
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and TechnologySapporo, Japan
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido UniversitySapporo, Japan
- Research Center for Advanced Science and Technology, The University of TokyoTokyo, Japan
| | - Rina Yoshida
- Department of Civil and Environmental Engineering, Nagaoka University of TechnologyNagaoka, Japan
| | - Takashi Yamaguchi
- Department of Civil and Environmental Engineering, Nagaoka University of TechnologyNagaoka, Japan
| | - Tomoyuki Sato
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and TechnologySapporo, Japan
| | - Isao Yumoto
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and TechnologySapporo, Japan
| | - Yoichi Kamagata
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and TechnologySapporo, Japan
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido UniversitySapporo, Japan
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33
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Hori T, Akuzawa M, Haruta S, Ueno Y, Ogata A, Ishii M, Igarashi Y. Involvement of a novel fermentative bacterium in acidification in a thermophilic anaerobic digester. FEMS Microbiol Lett 2014; 361:62-67. [PMID: 25273502 DOI: 10.1111/1574-6968.12611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/26/2014] [Accepted: 09/26/2014] [Indexed: 11/28/2022] Open
Abstract
Acidification results from the excessive accumulation of volatile fatty acids and the breakthrough of buffering capacity in anaerobic digesters. However, little is known about the identity of the acidogenic bacteria involved. Here, we identified an active fermentative bacterium during acidification in a thermophilic anaerobic digester by sequencing and phylogenetic analysis of isotopically labeled rRNA. The digestion sludge retrieved from the beginning of pH drop in the laboratory-scale anaerobic digester was incubated anaerobically at 55 °C for 4 h during which 13C-labeled glucose was supplemented repeatedly. 13CH4 and 13CO2 were produced after substrate addition. RNA extracts from the incubated sludge was density-separated by ultracentrifugation, and then bacterial communities in the density fractions were screened by terminal restriction fragment length polymorphism and clone library analyses based on 16S rRNA transcripts. Remarkably, a novel lineage within the genus Thermoanaerobacterium became abundant with increasing the buoyant density and predominated in the heaviest fraction of RNA. The results in this study indicate that a thermoacidophilic bacterium exclusively fermented the simple carbohydrate glucose, thereby playing key roles in acidification in the thermophilic anaerobic digester.
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Affiliation(s)
- Tomoyuki Hori
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan .,Research Institute for Environmental Management Technology, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan
| | - Masateru Akuzawa
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shin Haruta
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji-shi, Tokyo, Japan
| | - Yoshiyuki Ueno
- Kajima Technical Research Institute, Chofu-shi, Tokyo, Japan
| | - Atsushi Ogata
- Research Institute for Environmental Management Technology, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan
| | - Masaharu Ishii
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Yasuo Igarashi
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Research Center of Bioenergy and Bioremediation, Southwest University, BeiBei District, Chongqing, China
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Kato S, Sasaki K, Watanabe K, Yumoto I, Kamagata Y. Physiological and transcriptomic analyses of the thermophilic, aceticlastic methanogen Methanosaeta thermophila responding to ammonia stress. Microbes Environ 2014; 29:162-7. [PMID: 24920170 PMCID: PMC4103522 DOI: 10.1264/jsme2.me14021] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Accepted: 03/17/2014] [Indexed: 11/12/2022] Open
Abstract
The inhibitory effects of ammonia on two different degradation pathways of methanogenic acetate were evaluated using a pure culture (Methanosaeta thermophila strain PT) and defined co-culture (Methanothermobacter thermautotrophicus strain TM and Thermacetogenium phaeum strain PB), which represented aceticlastic and syntrophic methanogenesis, respectively. Growth experiments with high concentrations of ammonia clearly demonstrated that sensitivity to ammonia stress was markedly higher in M. thermophila PT than in the syntrophic co-culture. M. thermophila PT also exhibited higher sensitivity to high pH stress, which indicated that an inability to maintain pH homeostasis is an underlying cause of ammonia inhibition. Methanogenesis was inhibited in the resting cells of M. thermophila PT with moderate concentrations of ammonia, suggesting that the inhibition of enzymes involved in methanogenesis may be one of the major factors responsible for ammonia toxicity. Transcriptomic analysis revealed a broad range of disturbances in M. thermophila PT cells under ammonia stress conditions, including protein denaturation, oxidative stress, and intracellular cation imbalances. The results of the present study clearly demonstrated that syntrophic acetate degradation dominated over aceticlastic methanogenesis under ammonia stress conditions, which is consistent with the findings of previous studies on complex microbial community systems. Our results also imply that the co-existence of multiple metabolic pathways and their different sensitivities to stress factors confer resiliency on methanogenic processes.
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Affiliation(s)
- Souichiro Kato
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2–17–2–1 Tsukisamu-Higashi, Toyohira-ku, Sapporo, Hokkaido 062–8517, Japan
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo, Hokkaido 060–8589, Japan
- Research Center for Advanced Science and Technology, The University of Tokyo, 4–6–1 Komaba, Meguro-ku, Tokyo 153–8904, Japan
| | - Konomi Sasaki
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2–17–2–1 Tsukisamu-Higashi, Toyohira-ku, Sapporo, Hokkaido 062–8517, Japan
- Hokkaido High-Technology College, 2–12–1 Megumino-kita, Eniwa, Hokkaido 061–1374, Japan
| | - Kazuya Watanabe
- Research Center for Advanced Science and Technology, The University of Tokyo, 4–6–1 Komaba, Meguro-ku, Tokyo 153–8904, Japan
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432–1 Horinouchi, Hachioji, Tokyo 192–0392, Japan
| | - Isao Yumoto
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2–17–2–1 Tsukisamu-Higashi, Toyohira-ku, Sapporo, Hokkaido 062–8517, Japan
| | - Yoichi Kamagata
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2–17–2–1 Tsukisamu-Higashi, Toyohira-ku, Sapporo, Hokkaido 062–8517, Japan
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo, Hokkaido 060–8589, Japan
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Mulat DG, Ward AJ, Adamsen APS, Voigt NV, Nielsen JL, Feilberg A. Quantifying contribution of synthrophic acetate oxidation to methane production in thermophilic anaerobic reactors by membrane inlet mass spectrometry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:2505-2511. [PMID: 24437339 DOI: 10.1021/es403144e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A unique method was developed and applied for monitoring methanogenesis pathways based on isotope labeled substrates combined with online membrane inlet quadrupole mass spectrometry (MIMS). In our study, a fermentation sample from a full-scale biogas plant fed with pig and cattle manure, maize silage, and deep litter was incubated with 100 mM of [2-(13)C] sodium acetate under thermophilic anaerobic conditions. MIMS was used to measure the isotopic distribution of dissolved CO2 and CH4 during the degradation of acetate, while excluding interference from water by applying a cold trap. After 6 days of incubation, the proportion of methane derived from reduction of CO2 had increased significantly and reached up to 87% of total methane, suggesting that synthrophic acetate oxidation coupled to hydrogenotrophic methanogenesis (SAO-HM) played an important role in the degradation of acetate. This study provided a new approach for online quantification of the relative contribution of methanogenesis pathways to methane production with a time resolution shorter than one minute. The observed contribution of SAO-HM to methane production under the tested conditions challenges the current widely accepted anaerobic digestion model (ADM1), which strongly emphasizes the importance of the acetoclastic methanogenesis.
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Affiliation(s)
- Daniel Girma Mulat
- Department of Engineering, Aarhus University , Hangøvej 2, DK-8200 Aarhus N, Denmark
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Manyi-Loh CE, Mamphweli SN, Meyer EL, Okoh AI, Makaka G, Simon M. Microbial anaerobic digestion (bio-digesters) as an approach to the decontamination of animal wastes in pollution control and the generation of renewable energy. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:4390-417. [PMID: 24048207 PMCID: PMC3799523 DOI: 10.3390/ijerph10094390] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 09/09/2013] [Accepted: 09/10/2013] [Indexed: 11/16/2022]
Abstract
With an ever increasing population rate; a vast array of biomass wastes rich in organic and inorganic nutrients as well as pathogenic microorganisms will result from the diversified human, industrial and agricultural activities. Anaerobic digestion is applauded as one of the best ways to properly handle and manage these wastes. Animal wastes have been recognized as suitable substrates for anaerobic digestion process, a natural biological process in which complex organic materials are broken down into simpler molecules in the absence of oxygen by the concerted activities of four sets of metabolically linked microorganisms. This process occurs in an airtight chamber (biodigester) via four stages represented by hydrolytic, acidogenic, acetogenic and methanogenic microorganisms. The microbial population and structure can be identified by the combined use of culture-based, microscopic and molecular techniques. Overall, the process is affected by bio-digester design, operational factors and manure characteristics. The purpose of anaerobic digestion is the production of a renewable energy source (biogas) and an odor free nutrient-rich fertilizer. Conversely, if animal wastes are accidentally found in the environment, it can cause a drastic chain of environmental and public health complications.
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Affiliation(s)
- Christy E. Manyi-Loh
- Fort Hare Institute of Technology, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape Province, South Africa; E-Mails: (S.N.M.); (E.L.M.); (M.S.)
- Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape Province, South Africa; E-Mail:
| | - Sampson N. Mamphweli
- Fort Hare Institute of Technology, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape Province, South Africa; E-Mails: (S.N.M.); (E.L.M.); (M.S.)
| | - Edson L. Meyer
- Fort Hare Institute of Technology, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape Province, South Africa; E-Mails: (S.N.M.); (E.L.M.); (M.S.)
| | - Anthony I. Okoh
- Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape Province, South Africa; E-Mail:
| | - Golden Makaka
- Department of Physics, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape Province, South Africa; E-Mail:
| | - Michael Simon
- Fort Hare Institute of Technology, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape Province, South Africa; E-Mails: (S.N.M.); (E.L.M.); (M.S.)
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Mitsumori M, Matsui H, Tajima K, Shinkai T, Takenaka A, Denman SE, McSweeney CS. Effect of bromochloromethane and fumarate on phylogenetic diversity of the formyltetrahydrofolate synthetase gene in bovine rumen. Anim Sci J 2013; 85:25-31. [PMID: 23638678 DOI: 10.1111/asj.12072] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 02/25/2013] [Indexed: 11/30/2022]
Abstract
Effect of the methane inhibitor, bromochloromethane (BCM) and dietary substrate, fumarate, on microbial community structure of acetogen bacteria in the bovine rumen was investigated through analysis of the formyltetrahydrofolate synthetase gene (fhs). The fhs sequences obtained from BCM-untreated, BCM-treated, fumarate-untreated and fumarate-treated bovine rumen were categorized into homoacetogens and nonhomoacetogenic bacteria by homoacetogen similarity scores. Phylogenetic tree analysis indicated that most of the fhs sequences categorized into homoacetogens were divided into nine clusters, which were in close agreement with a result shown in a self-organizing map. The diversity of the fhs sequences from the BCM-treated rumen was significantly different from those from BCM-non-treated rumen. Principal component analysis also showed that addition of BCM to the rumen altered the population structure of acetogenic bacteria significantly but the effect of fumarate was comparatively minor. These results indicate that BCM affects diversity of actogens in the bovine rumen, and changes in acetogenic community structure in response to methane inhibitors may be caused by different mechanisms.
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Affiliation(s)
- Makoto Mitsumori
- National Institute of Livestock and Grassland Science, Tsukuba, Japan
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Müller B, Sun L, Schnürer A. First insights into the syntrophic acetate-oxidizing bacteria--a genetic study. Microbiologyopen 2012; 2:35-53. [PMID: 23239474 PMCID: PMC3584212 DOI: 10.1002/mbo3.50] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 10/18/2012] [Accepted: 11/05/2012] [Indexed: 11/10/2022] Open
Abstract
Syntrophic acetate-oxidizing bacteria have been identified as key organisms for efficient biogas production from protein-rich materials. They normally grow as lithotrophs or heterotrophs, producing acetate through the Wood–Ljungdahl pathway, but when growing in syntrophy with methanogens, they reportedly reverse this pathway and oxidize acetate to hydrogen and carbon dioxide. However, the biochemical and regulatory mechanisms behind the shift and the way in which the bacteria regain energy remain unknown. In a genome-walking approach, starting with degenerated primers, we identified those gene clusters in Syntrophaceticus schinkii, Clostridium ultunense, and Tepidanaerobacter acetatoxydans that comprise the formyltetrahydrofolate synthetase gene (fhs), encoding a key enzyme of the Wood–Ljungdahl pathway. We also discovered that the latter two harbor two fhs alleles. The fhs genes are phylogenetically separated and in the case of S. schinkii functionally linked to sulfate reducers. The T. acetatoxydansfhs1 cluster combines features of acetogens, sulfate reducers, and carbon monoxide oxidizers and is organized as a putative operon. The T. acetatoxydansfhs2 cluster encodes Wood–Ljungdahl pathway enzymes, which are also known to be involved in C1 carbon metabolism. Isolation of the enzymes illustrated that both formyltetrahydrofolate synthetases of T. acetatoxydans were functionally active. However, only fhs1 was expressed, confirming bidirectional usage of the pathway.
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Affiliation(s)
- Bettina Müller
- Department of Microbiology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala, SE 750 07, Sweden.
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Hao LP, Lü F, Li L, Shao LM, He PJ. Shift of pathways during initiation of thermophilic methanogenesis at different initial pH. BIORESOURCE TECHNOLOGY 2012; 126:418-424. [PMID: 22227145 DOI: 10.1016/j.biortech.2011.12.072] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 12/12/2011] [Accepted: 12/13/2011] [Indexed: 05/31/2023]
Abstract
To investigate the metabolic pathways during the initiation of methanogenesis from acid crisis, the influence of initial pH (5.0-6.5) on thermophilic methanogenic conversion of 100mmol/L acetate was monitored based on the isotopic signature and selective-inhibition method combined with analysis of the microbial structure. The results showed, lower pH extended the lag phase for methanogenesis which was inhibited at pH5.0 throughout the incubation. At initial pH6.0-6.5, methanogenesis was primarily initiated via acetoclastic methanogenesis (AM), with the fraction of the hydrogenotrophic pathway (f(mc)) accounting for 21-22% of total methane formation. Conversely, at initial pH5.5, the dominant pathway shifted to syntrophic acetate oxidation coupled with hydrogenotrophic methanogenesis (SAO-HM), with f(mc) rising to 51% and the abundance of syntrophic acetate-oxidizing bacteria increasing remarkably. Methanogenesis could initiate independently via SAO-HM pathway when AM pathway was inhibited. Acetate-oxidizing syntrophs could function as the initiation center of methanogenesis from low-pH crisis.
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Affiliation(s)
- Li-Ping Hao
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
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Montoya L, Celis LB, Razo-Flores E, Alpuche-Solís ÁG. Distribution of CO2 fixation and acetate mineralization pathways in microorganisms from extremophilic anaerobic biotopes. Extremophiles 2012; 16:805-17. [DOI: 10.1007/s00792-012-0487-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 09/27/2012] [Indexed: 11/28/2022]
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De Vrieze J, Hennebel T, Boon N, Verstraete W. Methanosarcina: the rediscovered methanogen for heavy duty biomethanation. BIORESOURCE TECHNOLOGY 2012; 112:1-9. [PMID: 22418081 DOI: 10.1016/j.biortech.2012.02.079] [Citation(s) in RCA: 435] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 02/13/2012] [Accepted: 02/16/2012] [Indexed: 05/07/2023]
Abstract
Anaerobic digestion is an important technology in the framework of renewable energy production. The anaerobic digestion system is susceptible to perturbations due to the sensitivity of the methanogens towards environmental factors. Currently, technology is evolving from conventional waste treatment, i.e. the removal of pollutants, to very intensive biogas production from concentrated wastes, in the framework of bio-energy production. In the latter configuration Methanosarcina species appear to be of crucial importance. Methanosarcina sp. are, compared to other methanogens, quite robust towards different impairments. They are reported to be tolerant to total ammonium concentrations up to 7000 mg L(-1), salt concentrations up to 18,000 mg Na(+)L(-1), a pH shock of 0.8-1.0 units and acetate concentrations up to 15,000 mg CODL(-1). The possibilities of Methanosarcina sp. as key organisms in specific types of anaerobic digestion systems are demonstrated in this review.
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Affiliation(s)
- Jo De Vrieze
- Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, B-9000 Gent, Belgium
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