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Krohn C, Jansriphibul K, Dias DA, Rees CA, Akker BVD, Boer JC, Plebanski M, Surapaneni A, O'Carroll D, Richard S, Batstone DJ, Ball AS. Dead in the water - Role of relic DNA and primer choice for targeted sequencing surveys of anaerobic sewage sludge intended for biological monitoring. Water Res 2024; 253:121354. [PMID: 38428359 DOI: 10.1016/j.watres.2024.121354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 03/03/2024]
Abstract
DNA-based monitoring of microbial communities that are responsible for the performance of anaerobic digestion of sewage wastes has the potential to improve resource recoveries for wastewater treatment facilities. By treating sludge with propidium monoazide (PMA) prior to amplicon sequencing, this study explored how the presence of DNA from dead microbial biomass carried over with feed sludge may mislead process-relevant biomarkers, and whether primer choice impacts such assessments. Four common primers were selected for amplicon preparation, also to determine if universal primers have sufficient taxonomic or functional coverage for monitoring ecological performance; or whether two domain-specific primers for Bacteria and Archaea are necessary. Anaerobic sludges of three municipal continuously stirred-tank reactors in Victoria, Australia, were sampled at one time-point. A total of 240 amplicon libraries were sequenced on a Miseq using two universal and two domain-specific primer pairs. Untargeted metabolomics was chosen to complement biological interpretation of amplicon gene-based functional predictions. Diversity, taxonomy, phylogeny and functional potentials were systematically assessed using PICRUSt2, which can predict community wide pathway abundance. The two chosen universal primers provided similar diversity profiles of abundant Bacteria and Archaea, compared to the domain-specific primers. About 16 % of all detected prokaryotic genera covering 30 % of total abundances and 6 % of PICRUSt2-estimated pathway abundances were affected by PMA. This showed that dead biomass in the anaerobic digesters impacted DNA-based assessments, with implications for predicting active processes, such as methanogenesis, denitrification or the identification of organisms associated with biological foams. Hence, instead of running two sequencing runs with two different domain-specific primers, we propose conducting PMA-seq with universal primer pairs for routine performance monitoring. However, dead sludge biomass may have some predictive value. In principal component analysis the compositional variation of 239 sludge metabolites resembled that of 'dead-plus-alive' biomass, suggesting that dead organisms contributed to the potentially process-relevant sludge metabolome.
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Affiliation(s)
- Christian Krohn
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Building 215, Level 3, Room 003-06, RMIT Bundoora West Campus, 225-245 Plenty Road, Bundoora, Victoria 3083, Australia.
| | - Kraiwut Jansriphibul
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Building 215, Level 3, Room 003-06, RMIT Bundoora West Campus, 225-245 Plenty Road, Bundoora, Victoria 3083, Australia
| | - Daniel A Dias
- Centre for Advanced Sensory Science (CASS) Food Research Centre, School of Exercise and Nutrition Sciences, Deakin University, Melbourne Burwood Campus, 221 Burwood Highway, Burwood, Victoria 3125, Australia
| | - Catherine A Rees
- Melbourne Water Corporation, 990 La Trobe Street, Docklands, Victoria 3008, Australia
| | - Ben van den Akker
- South Australian Water Corporation, Adelaide, South Australia 5000, Australia
| | - Jennifer C Boer
- Cancer Aging and Vaccine Laboratory, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria 3083, Australia
| | - Magdalena Plebanski
- Cancer Aging and Vaccine Laboratory, School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria 3083, Australia
| | - Aravind Surapaneni
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Building 215, Level 3, Room 003-06, RMIT Bundoora West Campus, 225-245 Plenty Road, Bundoora, Victoria 3083, Australia; South East Water, 101 Wells Street, Frankston, Victoria 3199, Australia
| | - Denis O'Carroll
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Stuetz Richard
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Damien J Batstone
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Building 215, Level 3, Room 003-06, RMIT Bundoora West Campus, 225-245 Plenty Road, Bundoora, Victoria 3083, Australia; Australian Centre for Water and Environmental Biotechnology (ACWEB), Gehrmann Building, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Andrew S Ball
- ARC Training Centre for the Transformation of Australia's Biosolids Resource, RMIT University, Building 215, Level 3, Room 003-06, RMIT Bundoora West Campus, 225-245 Plenty Road, Bundoora, Victoria 3083, Australia
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Hao L, Fan L, Chapleur O, Guenne A, Bize A, Bureau C, Lü F, He P, Bouchez T, Mazéas L. Gradual development of ammonia-induced syntrophic acetate-oxidizing activities under mesophilic and thermophilic conditions quantitatively tracked using multiple isotopic approaches. Water Res 2021; 204:117586. [PMID: 34474248 DOI: 10.1016/j.watres.2021.117586] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 08/13/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Insights into microbiota adaptation to increased ammonia stress, and identification of indicator microorganisms can help to optimize the operation of anaerobic digesters. To identify microbial indicators and investigate their metabolic contribution to acetoclastic methanogenesis (AM), syntrophic acetate oxidation (SAO) or hydrogenotrophic methanogenesis (HM), 40 anaerobic batch reactors fed with acetate of 110 mmol/L were set up at NH4+-N concentrations of 0.14 g/L, 5.00 g/L or 7.00 g/L, inoculated with thermophilic or mesophilic microbiota with or without pre-exposure to ammonia stress. Four stable carbon isotope probing approaches were applied in parallel, with [1,2-13C]-CH3COOH, [2-13C]-CH3COOH, [13C]NaHCO3 or non-labeled CH3COOH used individually. The last three approaches were used to quantify the methanogenic pathways by tracking labeled 13C or natural 13C signatures in the resulting CH4 and CO2, and consistently detected the dynamic transition of dominant pathways from AM to SAO-HM under ammonia stress. Results of quantitative PCR and fluorescence in-situ hybridization illustrated the procedure, acetotrophic methanogens being outcompeted by acetate-oxidizing syntrophs. The first and last isotope-labeling approaches were designed to probe the active acetate-mineralizing microbes with DNA-SIP. Known acetate-oxidizing bacteria like Syntrophaceticus and Tepidanaerobacter, as well as novel members of Pseudomonas, Bacillus and Symbiobacteraceae were detected, with Methanoculleus as the predominant H2/CO2-utilizing partner. Using NanoSIMS, some bacterial cells were observed to be fixing CO2 from [13C]NaHCO3. In this study, Methanosaeta was only active with ammonia < 200 mg-N/L; the syntrophs catalyzing SAO-HM started to compete with AM-conducting Methanosarcina at intermediate concentrations of ammonia, i.e. 200-500 mg-N/L, and outcompeted the acetotrophic methanogens with ammonia > 500 mg-N/L. Under ammonia stress, diverse known and novel microbial taxa were involved in acetate mineralization, comparable with those identified in previous studies.
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Affiliation(s)
- Liping Hao
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| | - Lu Fan
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| | - Olivier Chapleur
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, Antony 92761, France
| | - Angéline Guenne
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, Antony 92761, France
| | - Ariane Bize
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, Antony 92761, France
| | - Chrystelle Bureau
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, Antony 92761, France
| | - Fan Lü
- Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China
| | - Pinjing He
- Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China.
| | - Théodore Bouchez
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, Antony 92761, France.
| | - Laurent Mazéas
- Université Paris-Saclay, INRAE, PRocédés biOtechnologiques au Service de l'Environnement, Antony 92761, France.
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Zhang L, Guo B, Mou A, Li R, Liu Y. Blackwater biomethane recovery using a thermophilic upflow anaerobic sludge blanket reactor: Impacts of effluent recirculation on reactor performance. J Environ Manage 2020; 274:111157. [PMID: 32805474 DOI: 10.1016/j.jenvman.2020.111157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 07/03/2020] [Accepted: 07/29/2020] [Indexed: 06/11/2023]
Abstract
Thermophilic anaerobic digestion is a promising process for high-solid blackwater (BW) treatment due to improved hydrolysis rates, high methanogenesis efficiency, and pathogen removal, when compared with mesophilic treatment. In the present work, the effects of effluent recirculation (i.e., mixing) on thermophilic blackwater treatment were studied. A laboratory-scale thermophilic upflow anaerobic sludge blanket reactor was operated with and without effluent recirculation. The methanogenesis efficiency of the BW treatment increased from 45.0 ± 2.9% when effluent recirculation was applied to 56.7 ± 5.5% without effluent recirculation. Without effluent recirculation, the COD accumulation in the bioreactor was reduced from 17.2 to 3.8% and the effluent volatile fatty acids (VFA) concentration was reduced from 0.64 ± 0.18 to 0.15 ± 0.10 g/L. Further, both acetoclastic and hydrogenotrophic methanogenic activity increased from 101.3 ± 10.8 and 93.9 ± 6.1 to 120.4 ± 9.4 and 118.2 ± 13.2 mg CH4-COD/(gVSS⋅d), respectively, after effluent recirculation was discontinued. The predominant methanogens changed from Methanothermobacter (67%) with effluent recirculation to Methanosarcina (62%) without effluent recirculation. As compared to the effluent recirculation conditions, the enhanced biomethane recovery and treatment performance without effluent recirculation can be attributed to the close proximity of bacteria and archaea groups and the reduced VFA accumulation. Predicted functional gene comparison showed higher prevalence of function for intermediate metabolite transportation (transporters, ATP-binding cassette (ABC) transporters, and two-component system) after discontinuing effluent circulation, which contributed to improved syntrophic propionate oxidation and syntrophic acetate oxidization and enhanced hydrogenotrophic methanogenesis.
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Affiliation(s)
- Lei Zhang
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada
| | - Bing Guo
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada
| | - Anqi Mou
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada
| | - Ran Li
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada; College of Petroleum Engineering, Xi'an Shiyou University, Xi'an, 710065, Shaanxi Province, China
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Canada.
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Shen N, Liang Z, Chen Y, Song H, Wan J. Enhancement of syntrophic acetate oxidation pathway via single walled carbon nanotubes addition under high acetate concentration and thermophilic condition. Bioresour Technol 2020; 306:123182. [PMID: 32199400 DOI: 10.1016/j.biortech.2020.123182] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/07/2020] [Accepted: 03/12/2020] [Indexed: 06/10/2023]
Abstract
The effect of single walled carbon nanotubes (SWCNT) on methane production under high acetate concentration and thermophilic condition was evaluated. An isotope labeling experiment verified that >85% of methane was generated from syntrophic acetate oxidation (SAO) at 50, 100 and 150 mM acetate and almost 100% at 200 mM. SWCNT addition had little effect on the methanogenesis pathway, whereas it accelerated methane production via decreasing lag phase times and increasing maximum methane production rates. Electrochemical impedance spectroscopy (EIS) results revealed the electrical resistivity of sludge in groups of SWCNT was distinctly smaller than CK groups, indicating higher sludge conductivity was achieved. Further, the results of communities described that Coprothermobacter and Thermacetogenium played the most important role in SAO under all conditions. Meanwhile, the enriched Thermacetogenium and direct interspecies electron transfer (DIET) pathway in SAO consortia contributed to the acceleration of methane production via SWCNT addition.
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Affiliation(s)
- Nan Shen
- School of Environment, Nanjing Normal University, Nanjing, Jiangsu 210023, People's Republic of China
| | - Zhu Liang
- School of Environment, Nanjing Normal University, Nanjing, Jiangsu 210023, People's Republic of China
| | - Yun Chen
- School of Environment, Nanjing Normal University, Nanjing, Jiangsu 210023, People's Republic of China.
| | - Hailiang Song
- School of Environment, Nanjing Normal University, Nanjing, Jiangsu 210023, People's Republic of China
| | - Junfeng Wan
- School of Ecology and Environment, Zhengzhou University, Zhengzhou, Henan 450001, People's Republic of China
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Xu J, Bu F, Zhu W, Luo G, Xie L. Microbial Consortiums of Hydrogenotrophic Methanogenic Mixed Cultures in Lab-Scale Ex-Situ Biogas Upgrading Systems under Different Conditions of Temperature, pH and CO. Microorganisms 2020; 8:microorganisms8050772. [PMID: 32455626 PMCID: PMC7285331 DOI: 10.3390/microorganisms8050772] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 05/15/2020] [Accepted: 05/18/2020] [Indexed: 12/12/2022] Open
Abstract
In this study, hydrogenotrophic methanogenic mixed cultures taken from 13 lab-scale ex-situ biogas upgrading systems under different temperature (20–70 °C), pH (6.0–8.5), and CO (0–10%, v/v) variables were systematically investigated. High-throughput 16S rRNA gene sequencing was used to identify the microbial consortia, and statistical analyses were conducted to reveal the microbial diversity, the core functional microbes, and their correlative relationships with tested variables. Overall, bacterial community was more complex than the archaea community in all mixed cultures. Hydrogenotrophic methanogens Methanothermobacter, Methanobacterium, and Methanomassiliicoccus, and putative syntrophic acetate-oxidizing bacterium Coprothermobacter and Caldanaerobacter were found to predominate, but the core functional microbes varied under different conditions. Multivariable sensitivity analysis indicated that temperature (p < 0.01) was the crucial variable to determine the microbial consortium structures in hydrogenotrophic methanogenic mixed cultures. pH (0.01 < p < 0.05) significantly interfered with the relative abundance of dominant archaea. Although CO did not affect community (p > 0.1), some potential CO-utilizing syntrophic metabolisms might be enhanced. Understanding of microbial consortia in the hydrogenotrophic methanogenic mixed cultures related to environmental variables was a great advance to reveal the microbial ecology in microbial biogas upgrading process.
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Affiliation(s)
- Jun Xu
- The Yangtze River Water Environment Key Laboratory of the Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; (J.X.); (F.B.); (W.Z.)
| | - Fan Bu
- The Yangtze River Water Environment Key Laboratory of the Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; (J.X.); (F.B.); (W.Z.)
| | - Wenzhe Zhu
- The Yangtze River Water Environment Key Laboratory of the Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; (J.X.); (F.B.); (W.Z.)
| | - Gang Luo
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200092, China;
| | - Li Xie
- The Yangtze River Water Environment Key Laboratory of the Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; (J.X.); (F.B.); (W.Z.)
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
- Correspondence:
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Zheng D, Wang H, Gou M, Nobu MK, Narihiro T, Hu B, Nie Y, Tang Y. Identification of novel potential acetate-oxidizing bacteria in thermophilic methanogenic chemostats by DNA stable isotope probing. Appl Microbiol Biotechnol 2019; 103:8631-45. [DOI: 10.1007/s00253-019-10078-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 06/30/2019] [Accepted: 07/31/2019] [Indexed: 01/04/2023]
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Abstract
Syntrophic acetate oxidation (SAO) plays a pivotal role in biogas production processes when aceticlastic methanogens are inhibited. Despite the importance of SAO, the metabolic interactions and syntrophic growth of the organisms involved are still poorly understood. Therefore, we studied growth parameters and interactions within constructed defined cocultures comprising the methanogen Methanoculleus bourgensis and one, or several, of the syntrophic acetate oxidizers Syntrophaceticus schinkii, [ Clostridium] ultunense, and Tepidanaerobacter acetatoxydans and a novel, uncharacterized bacterium. Cultivation experiments in a design-of-experiment approach revealed positive effects on methane production rate of increased ammonium levels (up to 0.2 M), temperature (up to 45 °C), and acetate concentrations (0.15-0.30 M). Molecular analyses and thermodynamic calculations demonstrated close interlinkages between the microorganisms, with available energies of -10 kJ/mol for acetate oxidation and -20 kJ/mol for hydrogenotrophic methanogenesis. The estimated generation time varied between 3 and 20 days for all syntrophic microorganisms involved, and the acetate minimum threshold level was 0.40-0.45 mM. The rate of methanogenesis depended on the SAO bacteria present in the culture. These data are beneficial for interpretation of SAO prevalence and competiveness against aceticlastic methanogens in anaerobic environments.
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Affiliation(s)
- Maria Westerholm
- Department of Microbiology , Swedish University of Agricultural Sciences , Uppsala BioCenter, Box 7025, SE-750 07 Uppsala , Sweden
| | - Jan Dolfing
- School of Engineering , Newcastle University , Newcastle-upon-Tyne NE1 7RU United Kingdom
| | - Anna Schnürer
- Department of Microbiology , Swedish University of Agricultural Sciences , Uppsala BioCenter, Box 7025, SE-750 07 Uppsala , Sweden
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Rotaru AE, Calabrese F, Stryhanyuk H, Musat F, Shrestha PM, Weber HS, Snoeyenbos-West OLO, Hall POJ, Richnow HH, Musat N, Thamdrup B. Conductive Particles Enable Syntrophic Acetate Oxidation between Geobacter and Methanosarcina from Coastal Sediments. mBio 2018; 9:e00226-18. [PMID: 29717006 DOI: 10.1128/mBio.00226-18] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Coastal sediments are rich in conductive particles, possibly affecting microbial processes for which acetate is a central intermediate. In the methanogenic zone, acetate is consumed by methanogens and/or syntrophic acetate-oxidizing (SAO) consortia. SAO consortia live under extreme thermodynamic pressure, and their survival depends on successful partnership. Here, we demonstrate that conductive particles enable the partnership between SAO bacteria (i.e., Geobacter spp.) and methanogens (Methanosarcina spp.) from the coastal sediments of the Bothnian Bay of the Baltic Sea. Baltic methanogenic sediments were rich in conductive minerals, had an apparent isotopic fractionation characteristic of CO2-reductive methanogenesis, and were inhabited by Geobacter and Methanosarcina. As long as conductive particles were delivered, Geobacter and Methanosarcina persisted, whereas exclusion of conductive particles led to the extinction of Geobacter. Baltic Geobacter did not establish a direct electric contact with Methanosarcina, necessitating conductive particles as electrical conduits. Within SAO consortia, Geobacter was an efficient [13C]acetate utilizer, accounting for 82% of the assimilation and 27% of the breakdown of acetate. Geobacter benefits from the association with the methanogen, because in the absence of an electron acceptor it can use Methanosarcina as a terminal electron sink. Consequently, inhibition of methanogenesis constrained the SAO activity of Geobacter as well. A potential benefit for Methanosarcina partnering with Geobacter is that together they competitively exclude acetoclastic methanogens like Methanothrix from an environment rich in conductive particles. Conductive particle-mediated SAO could explain the abundance of acetate oxidizers like Geobacter in the methanogenic zone of sediments where no electron acceptors other than CO2 are available. Acetate-oxidizing bacteria are known to thrive in mutualistic consortia in which H2 or formate is shuttled to a methane-producing Archaea partner. Here, we discovered that such bacteria could instead transfer electrons via conductive minerals. Mineral SAO (syntrophic acetate oxidation) could be a vital pathway for CO2-reductive methanogenesis in the environment, especially in sediments rich in conductive minerals. Mineral-facilitated SAO is therefore of potential importance for both iron and methane cycles in sediments and soils. Additionally, our observations imply that agricultural runoff or amendments with conductive chars could trigger a significant increase in methane emissions.
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Chen Y, Xiao K, Jiang X, Shen N, Zeng RJ, Zhou Y. In-situ sludge pretreatment in a single-stage anaerobic digester. Bioresour Technol 2017; 238:102-108. [PMID: 28433896 DOI: 10.1016/j.biortech.2017.04.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 03/31/2017] [Accepted: 04/05/2017] [Indexed: 06/07/2023]
Abstract
This study aimed to develop an in-situ sludge pretreatment method by increasing the temperature from thermophilic to extreme thermophilic condition in a single-stage anaerobic digester. The results revealed that a stable performance was obtained within the temperature range of 55-65°C, and the maximum methane yield of 208.51±13.66mL/g VS was obtained at 65°C. Moreover, the maximum extent of hydrolysis (33%) and acidification (27.1%) was also observed at 65°C. However, further increase of temperature to 70°C did not improve the organic conversion efficiency. Microbial community analysis revealed that Coprothermobacter, highly related to acetate oxidisers, appeared to be the abundant bacterial group at higher temperature. A progressive shift in methanogenic members from Methanosarcina to Methanothermobacter was observed upon increasing the temperature. This work demonstrated single-stage sludge digestion system can be successfully established at high temperature (65°C) with stable performance, which can eliminate the need of conventional thermophilic pretreatment step.
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Affiliation(s)
- Yun Chen
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Keke Xiao
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore
| | - Xie Jiang
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore
| | - Nan Shen
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore
| | - Raymond J Zeng
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Yan Zhou
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
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