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Pérez-de-Mora A, de Wilde H, Paulus D, Roosa S, Onderwater R, Paint Y, Avignone Rossa C, Farkas D. Biostimulation of sulfate reduction for in-situ metal(loid) precipitation at an industrial site in Flanders, Belgium. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 929:172298. [PMID: 38615778 DOI: 10.1016/j.scitotenv.2024.172298] [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: 12/29/2023] [Revised: 03/17/2024] [Accepted: 04/05/2024] [Indexed: 04/16/2024]
Abstract
A 30-month pilot study was conducted to evaluate the potential of in-situ metal(loid) removal through biostimulation of sulfate-reducing processes. The study took place at an industrial site in Flanders, Belgium, known for metal(loid) contamination in soil and groundwater. Biostimulation involved two incorporations of an organic substrate (emulsified vegetable oil) as electron donor and potassium bicarbonate to raise the pH of the groundwater by 1-1.5 units. The study focused on the most impacted permeable fine sand aquifer (8-9 m below groundwater level) confined by layers of non-permeable clay. The fine sands exhibited initially oxic conditions (50-200 mV), an acidic pH of 4.5 and sulfate concentrations ranging from 600 to 800 mg/L. At the central monitoring well, anoxic conditions (-200 to -400 mV) and a pH of 5.9 established shortly after the second substrate and reagent injection. Over the course of 12 months, there was a significant decrease in the concentration of arsenic (from 2500 to 12 μg/L), nickel (from 360 to <2 μg/L), zinc (from 78,000 to <2 μg/L), and sulfate (from 930 to 450 mg/L). Low levels of metal(loid)s were still present after 34 months (end of study). Mineralogical analysis indicated that the precipitates formed were amorphous in nature. Evidence for biologically driven metal(loid) precipitation was provided by compound specific stable isotope analysis of sulfate. In addition, changes in microbial populations were assessed using next-generation sequencing, revealing stimulation of native sulfate-reducing bacteria. These results highlight the potential of biostimulation for long-term in situ metal(loid) plume treatment/containment.
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Affiliation(s)
| | - Herwig de Wilde
- TAUW België nv, Dept. of Soil & Groundwater, Waaslandlaan 8A3, 9160 Lokeren, Belgium
| | - Dirk Paulus
- TAUW België nv, Dept. of Soil & Groundwater, Remylaan 4C, Bus 3, 3018 Leuven, Belgium
| | - Stephanie Roosa
- Materia NOVA Institute, 6 Avenue du champ de Mars, 7000 Mons, Belgium
| | - Rob Onderwater
- Materia NOVA Institute, 6 Avenue du champ de Mars, 7000 Mons, Belgium
| | - Yoann Paint
- Materia NOVA Institute, 6 Avenue du champ de Mars, 7000 Mons, Belgium
| | - Claudio Avignone Rossa
- University of Surrey, Deptartment of Microbial Sciences, Guildford GU2 7XH, United Kingdom
| | - Daniel Farkas
- University of Surrey, Deptartment of Microbial Sciences, Guildford GU2 7XH, United Kingdom.
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2
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Singh S, Keating C, Ijaz UZ, Hassard F. Molecular insights informing factors affecting low temperature anaerobic applications: Diversity, collated core microbiomes and complexity stability relationships in LCFA-fed systems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 874:162420. [PMID: 36842571 DOI: 10.1016/j.scitotenv.2023.162420] [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: 11/30/2022] [Revised: 01/31/2023] [Accepted: 02/19/2023] [Indexed: 06/18/2023]
Abstract
Fats, oil and grease, and their hydrolyzed counterparts-long chain fatty acids (LCFA) make up a large fraction of numerous wastewaters and are challenging to degrade anaerobically, more so, in low temperature anaerobic digestion (LtAD) systems. Herein, we perform a comparative analysis of publicly available Illumina 16S rRNA datasets generated from LCFA-degrading anaerobic microbiomes at low temperatures (10 and 20 °C) to comprehend the factors affecting microbial community dynamics. The various factors considered were the inoculum, substrate and operational characteristics, the reactor operation mode and reactor configuration, and the type of nucleic acid sequenced. We found that LCFA-degrading anaerobic microbiomes were differentiated primarily by inoculum characteristics (inoculum source and morphology) in comparison to the other factors tested. Inoculum characteristics prominently shaped the species richness, species evenness and beta-diversity patterns in the microbiomes even after long term operation of continuous reactors up to 150 days, implying the choice of inoculum needs careful consideration. The generalised additive models represented through beta diversity contour plots revealed that psychrophilic bacteria RBG-13-54-9 from family Anaerolineae, and taxa WCHB1-41 and Williamwhitmania were highly abundant in LCFA-fed microbial niches, suggesting their role in anaerobic treatment of LCFAs at low temperatures of 10-20 °C. Overall, we showed that the following bacterial genera: uncultured Propionibacteriaceae, Longilinea, Christensenellaceae R7 group, Lactivibrio, candidatus Caldatribacterium, Aminicenantales, Syntrophus, Syntrophomonas, Smithella, RBG-13-54-9, WCHB1-41, Trichococcus, Proteiniclasticum, SBR1031, Lutibacter and Lentimicrobium have prominent roles in LtAD of LCFA-rich wastewaters at 10-20 °C. This study provides molecular insights of anaerobic LCFA degradation under low temperatures from collated datasets and will aid in improving LtAD systems for treating LCFA-rich wastewaters.
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Affiliation(s)
- Suniti Singh
- Cranfield Water Science Institute, Cranfield University, College Way, Bedfordshire MK43 0AL, UK.
| | - Ciara Keating
- School of Biodiversity, One Health and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK.
| | - Umer Zeeshan Ijaz
- Infrastructure and Environment Research Division, James Watt School of Engineering, University of Glasgow, UK; Department of Molecular and Clinical Cancer Medicine, University of Liverpool, UK; College of Science and Engineering, NUI Galway, Ireland.
| | - Francis Hassard
- Cranfield Water Science Institute, Cranfield University, College Way, Bedfordshire MK43 0AL, UK; Institute for Nanotechnology and Water Sustainability, University of South Africa, UNISA Science Campus, 1710 Roodepoort, Johannesburg, South Africa.
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Li X, Yang Y, Lu CS, Kobayashi T, Kong Z, Hu Y. Oleate Impacts on Acetoclastic and Hydrogenotrophic Methanogenesis under Mesophilic and Thermophilic Conditions. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:3423. [PMID: 36834117 PMCID: PMC9960261 DOI: 10.3390/ijerph20043423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/07/2023] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
This study investigated oleate inhibition concentration on mesophilic and thermophilic sludge by utilizing acetate and H2/CO2 (80:20, v/v) as substrate, respectively. In addition, another batch experiment was carried out to explore the influence of oleate loads (mM-oleate/g-VS) on methane production. Generally, the mesophilic anaerobic system was more stable than the thermophilic system, which embodied higher microbial abundance, higher methane yield, and higher oleate tolerance. Furthermore, this study provides a possible methanogenic pathway impacted by oleate under mesophilic and thermophilic conditions according to functional microbial composition. Lastly, this paper provides noticeable and avoidable oleate concentrations and loads under different experimental conditions as a guide for future anaerobic bioreactors of lipidic waste biodegradation.
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Affiliation(s)
- Xiang Li
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Yang Yang
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Chen-Shun Lu
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Takuro Kobayashi
- Material Cycles Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan
| | - Zhe Kong
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Yong Hu
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, China
- Material Cycles Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan
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4
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Anaerobic membrane bioreactor-based treatment of poultry slaughterhouse wastewater: Microbial community adaptation and antibiotic resistance gene profiles. Biochem Eng J 2023. [DOI: 10.1016/j.bej.2023.108847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Novel Long-Chain Fatty Acid (LCFA)-Degrading Bacteria and Pathways in Anaerobic Digestion Promoted by Hydrochar as Revealed by Genome-Centric Metatranscriptomics Analysis. Appl Environ Microbiol 2022; 88:e0104222. [PMID: 35938788 PMCID: PMC9397102 DOI: 10.1128/aem.01042-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A large amount of long-chain fatty acids (LCFA) are generated after lipids hydrolysis in anaerobic digestion (AD), and LCFA are difficult to be biodegraded. This study showed that hydrochar (HC), which was produced during the hydrothermal liquefaction of organic wastes, significantly increased the methane production rate (by 56.9%) of oleate, a typical refractory model LCFA. Genomic-centric metatranscriptomics analysis revealed that three novel microbes (Bin138 Spirochaetota sp., Bin35 Smithellaceae sp., and Bin54 Desulfomonilia sp.) that were capable of degrading LCFA were enriched by HC, which played an important role in the degradation of oleate. LCFA was degraded to acetate through the well-known LCFA β-oxidation pathway and the combined β-oxidation and butyrate oxidation pathway. In addition, it was found that HC promoted the direct interspecies electron transfer (DIET) between Methanothrix sp. and Bin54 Desulfomonilia sp. The enriched new types of LCFA-degrading bacteria and the promotion of DIET contributed to the improved methane production rate of oleate by HC. IMPORTANCE Long-chain fatty acids (LCFA) are difficult to be degraded in anaerobic digestion (AD), and the known LCFA degrading bacteria are only limited to the families Syntrophomonadaceae and Syntrophaceae. Here, we found that hydrochar effectively promoted AD of LCFA, and the new LCFA-degrading bacteria and a new metabolic pathway were also revealed based on genomic-centric metatranscriptomic analysis. This study provided a new method for enhancing the AD of organic wastes with high content of LCFA and increased the understanding of the microbes and their metabolic pathways involved in AD of LCFA.
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Holohan BC, Duarte MS, Szabo-Corbacho MA, Cavaleiro AJ, Salvador AF, Pereira MA, Ziels RM, Frijters CTMJ, Pacheco-Ruiz S, Carballa M, Sousa DZ, Stams AJM, O'Flaherty V, van Lier JB, Alves MM. Principles, Advances, and Perspectives of Anaerobic Digestion of Lipids. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:4749-4775. [PMID: 35357187 DOI: 10.1021/acs.est.1c08722] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Several problems associated with the presence of lipids in wastewater treatment plants are usually overcome by removing them ahead of the biological treatment. However, because of their high energy content, waste lipids are interesting yet challenging pollutants in anaerobic wastewater treatment and codigestion processes. The maximal amount of waste lipids that can be sustainably accommodated, and effectively converted to methane in anaerobic reactors, is limited by several problems including adsorption, sludge flotation, washout, and inhibition. These difficulties can be circumvented by appropriate feeding, mixing, and solids separation strategies, provided by suitable reactor technology and operation. In recent years, membrane bioreactors and flotation-based bioreactors have been developed to treat lipid-rich wastewater. In parallel, the increasing knowledge on the diversity of complex microbial communities in anaerobic sludge, and on interspecies microbial interactions, contributed to extend the knowledge and to understand more precisely the limits and constraints influencing the anaerobic biodegradation of lipids in anaerobic reactors. This critical review discusses the most important principles underpinning the degradation process and recent key discoveries and outlines the current knowledge coupling fundamental and applied aspects. A critical assessment of knowledge gaps in the field is also presented by integrating sectorial perspectives of academic researchers and of prominent developers of anaerobic technology.
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Affiliation(s)
- B Conall Holohan
- Microbial Ecology Laboratory, Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland, Galway H91 TK33, Ireland
- NVP Energy Ltd., IDA Technology and Business Park, Mervue, Galway H91 TK33, Ireland
| | - M Salomé Duarte
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
- LABBELS - Associate Laboratory, 4710-057 Braga, Guimarães, Portugal
| | - M Alejandra Szabo-Corbacho
- Department of Environmental Engineering and Water Technology, IHE Delft Institute for Water Education, Westvest 7, 2611 AX Delft, The Netherlands
| | - Ana J Cavaleiro
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
- LABBELS - Associate Laboratory, 4710-057 Braga, Guimarães, Portugal
| | - Andreia F Salvador
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
- LABBELS - Associate Laboratory, 4710-057 Braga, Guimarães, Portugal
| | - M Alcina Pereira
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
- LABBELS - Associate Laboratory, 4710-057 Braga, Guimarães, Portugal
| | - Ryan M Ziels
- Department of Civil Engineering, The University of British Columbia, 6250 Applied Science Lane, Vancouver, BC V6T 1Z 4, Canada
| | | | - Santiago Pacheco-Ruiz
- Biothane, Veolia Water Technologies, Tanthofdreef 21, 2623 EW Delft, The Netherlands
| | - Marta Carballa
- CRETUS, Department of Chemical Engineering, Universidad de Santiago de Compostela, 15705 Santiago de Compostela, Spain
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University and Research, 6708 WE, Wageningen, The Netherlands
| | - Alfons J M Stams
- Laboratory of Microbiology, Wageningen University and Research, 6708 WE, Wageningen, The Netherlands
| | - Vincent O'Flaherty
- Microbial Ecology Laboratory, Microbiology, School of Natural Sciences and Ryan Institute, National University of Ireland, Galway H91 TK33, Ireland
| | - Jules B van Lier
- Department of Environmental Engineering and Water Technology, IHE Delft Institute for Water Education, Westvest 7, 2611 AX Delft, The Netherlands
- Section Sanitary Engineering, CEG Faculty, Delft University of Technology, 2628 CN, Delft, The Netherlands
| | - M Madalena Alves
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
- LABBELS - Associate Laboratory, 4710-057 Braga, Guimarães, Portugal
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Singh S, Rinta-Kanto JM, Lens PNL, Kokko M, Rintala J, O'Flaherty V, Ijaz UZ, Collins G. Microbial community assembly and dynamics in Granular, Fixed-Biofilm and planktonic microbiomes valorizing Long-Chain fatty acids at 20 °C. BIORESOURCE TECHNOLOGY 2022; 343:126098. [PMID: 34626764 DOI: 10.1016/j.biortech.2021.126098] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 10/03/2021] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
Distinct microbial assemblages evolve in anaerobic digestion (AD) reactors to drive sequential conversions of organics to methane. The spatio-temporal development of three such assemblages (granules, biofilms, planktonic) derived from the same inoculum was studied in replicated bioreactors treating long-chain fatty acids (LCFA)-rich wastewater at 20 °C at hydraulic retention times (HRTs) of 12-72 h. We found granular, biofilm and planktonic assemblages differentiated by diversity, structure, and assembly mechanisms; demonstrating a spatial compartmentalisation of the microbiomes from the initial community reservoir. Our analysis linked abundant Methanosaeta and Syntrophaceae-affiliated taxa (Syntrophus and uncultured) to their putative, active roles in syntrophic LCFA bioconversion. LCFA loading rates (stearate, palmitate), and HRT, were significant drivers shaping microbial community dynamics and assembly. This study of the archaea and syntrophic bacteria actively valorising LCFAs at short HRTs and 20 °C will help uncover the microbiology underpinning anaerobic bioconversions of fats, oil and grease.
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Affiliation(s)
- Suniti Singh
- Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, FI-33104 Tampere University, Finland; UNESCO-IHE, Institute for Water Education, Westvest 7, 2611AX Delft, the Netherlands; School of Chemical and Biological Sciences, and Ryan Institute, National University of Ireland Galway, University Road, Galway H91 TK33, Ireland
| | - Johanna M Rinta-Kanto
- Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, FI-33104 Tampere University, Finland
| | - Piet N L Lens
- Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, FI-33104 Tampere University, Finland; UNESCO-IHE, Institute for Water Education, Westvest 7, 2611AX Delft, the Netherlands
| | - Marika Kokko
- Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, FI-33104 Tampere University, Finland
| | - Jukka Rintala
- Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, FI-33104 Tampere University, Finland
| | - Vincent O'Flaherty
- School of Chemical and Biological Sciences, and Ryan Institute, National University of Ireland Galway, University Road, Galway H91 TK33, Ireland
| | - Umer Zeeshan Ijaz
- Water and Environment Group, School of Engineering, University of Glasgow, Glasgow G12 8LT, United Kingdom.
| | - Gavin Collins
- School of Chemical and Biological Sciences, and Ryan Institute, National University of Ireland Galway, University Road, Galway H91 TK33, Ireland; Water and Environment Group, School of Engineering, University of Glasgow, Glasgow G12 8LT, United Kingdom
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8
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Guo B, Yu N, Weissbrodt DG, Liu Y. Effects of micro-aeration on microbial niches and antimicrobial resistances in blackwater anaerobic digesters. WATER RESEARCH 2021; 196:117035. [PMID: 33751974 DOI: 10.1016/j.watres.2021.117035] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/02/2021] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
Anaerobic digestion (AD) of source-diverted blackwater (toilet flush) at ambient room temperature presents challenges for fast hydrolysis of particulate matters. This study investigated the effect of different micro-aeration dosages for blackwater AD. Sequencing batch reactors were operated at ambient room temperature (22 ± 1°C) with micro-aeration (0, 5, 10, 50, and 150 mg O2 g-1 CODfeed per cycle) and gradually reduced hydraulic retention times from 5 d to 2 d. The methanogenesis efficiencies were greater at low oxygen dosages (i.e., 0, 5, 10) while the volatile fatty acids (VFAs) accumulated more at high oxygen dosages (i.e., 50, 150). Microbial communities were significantly different under different oxygen dosages (p<0.05), with segregation of microbial ecological niches in low and high oxygen dosage communities. The low-oxygen-dosage niche (0, 5, and 10 mg g-1 CODfeed) was inhabited by fermenting and syntrophic bacteria (e.g., Cytophaga, Syntrophomonas) and methanogens (e.g., Methanobacterium, Methanolinea, Methanosaeta). The high-oxygen-dosage niche (50 and 150 mg g-1 CODfeed) had significantly (p<0.05) more facultative anaerobic bacteria (Ignavibacteriales and Cloacamonales), and aerobic bacteria (Rhodocyclales). Moreover, blackwater can be a source of antimicrobial resistance genes (ARGs), which are affected by different oxygen dosages. The ARG variation correlated with the microbial community composition (p<0.05). Low-oxygen-dosage communities contained a higher prevalence of mobile gene elements (intI1 and korB) and tetM, ermB, sul1, sul2, and blaCTX-M than the high-oxygen-dosage communities, indicating that oxygen dosage influenced the prevalence of populations carrying ARGs. These findings suggest that application of micro-aeration to AD can be used to control ARG profiles.
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Affiliation(s)
- Bing Guo
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada; Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Najiaowa Yu
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
| | - David G Weissbrodt
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada.
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Basak B, Patil SM, Saha S, Kurade MB, Ha GS, Govindwar SP, Lee SS, Chang SW, Chung WJ, Jeon BH. Rapid recovery of methane yield in organic overloaded-failed anaerobic digesters through bioaugmentation with acclimatized microbial consortium. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 764:144219. [PMID: 33421748 DOI: 10.1016/j.scitotenv.2020.144219] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/27/2020] [Accepted: 11/29/2020] [Indexed: 06/12/2023]
Abstract
Acidification during anaerobic digestion (AD) due to organic overloading is one of the major reasons for process failures and decreased methane productivity in anaerobic digesters. Process failures can cause the anaerobic digesters to stall completely, prolong the digester recovery period, and inflict an increased operational cost on wastewater treatment plants and adverse impacts on the environment. This study investigated the efficacy of bioaugmentation by using acclimatized microbial consortium (AC) in recovering anaerobic digesters stalled due to acidosis. Overloading of digesters with food waste leachate (FWL) led to the accumulation of volatile fatty acids (11.30 g L-1) and a drop in pH (4.67), which resulted in process failure and a 22-fold decline in cumulative methane production compared to that in the initial phase. In the failure phase, the syntrophic and methanogenic activities of the anaerobic digester microbiota were disrupted by a significant decrease in the abundance of syntrophic populations such as Syntrophomonas, Syntrophorhabdus, Sedimentibacter, and Levilinea, and the phylum Euryarchaeota. Bioaugmentation of the failed digesters by adding AC along with the adjustment of pH resulted in the prompt recovery of methane productivity with a 15.7-fold higher yield than that in unaugmented control. The abundance of syntrophic bacteria Syntrophomonas and phylum Euryarchaeota significantly increased by 29- and 17-fold in the recovered digesters, respectively, which showed significant positive correlations with methane productivity. Methanosarcina and acetoclastic Methanosaeta played a major role in the recovery of the digesters; they were later replaced by hydrogenotrophic Methanoculleus. The increase in the abundance of genes associated with biomethanation contributed to digester recovery, according to the functional annotation of 16S rDNA amplicon data. Thus, bioaugmentation with AC could be a viable solution to recover digesters experiencing process failure due to organic overloading.
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Affiliation(s)
- Bikram Basak
- Department of Earth Resources & Environmental Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Swapnil M Patil
- Department of Earth Resources & Environmental Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Shouvik Saha
- Department of Earth Resources & Environmental Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Mayur B Kurade
- Department of Earth Resources & Environmental Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
| | - Geon-Soo Ha
- Department of Earth Resources & Environmental Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Sanjay P Govindwar
- Department of Earth Resources & Environmental Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Sean S Lee
- Department of Earth Resources & Environmental Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Soon Woong Chang
- Department of Environmental Energy Engineering, Kyonggi University, 154-42 Gwanggyosan-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16227, Republic of Korea
| | - Woo Jin Chung
- Department of Environmental Energy Engineering, Kyonggi University, 154-42 Gwanggyosan-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16227, Republic of Korea
| | - Byong-Hun Jeon
- Department of Earth Resources & Environmental Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
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Hao J, de Los Reyes Iii FL, He X. Fat, oil, and grease (FOG) deposits yield higher methane than FOG in anaerobic co-digestion with waste activated sludge. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 268:110708. [PMID: 32510442 DOI: 10.1016/j.jenvman.2020.110708] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 04/21/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
The formation of fat, oil, and grease (FOG) deposits in sewers is a global challenge for the maintenance of sewer collection systems. Tons of FOG deposits (FDs) are removed from sewer systems every year and present an opportunity for increased methane production via anaerobic co-digestion with waste activated sludge (WAS) at water resource recovery facilities with existing anaerobic digesters. We hypothesized that FDs have higher biomethane potential than that of FOG (e.g., FOG collected in grease interceptors), because of the reduction of inhibition of long chain fatty acids due to saponification. In this study, substantially enhanced methane production was found in anaerobic co-digestion of WAS with FDs within the substrate to inoculum (S/I) ratio range of 0.25-1.2, and the maximum ultimate methane production (685.7 ± 24.1 mL/gVSadded, at S/I = 0.5) was 4.0 times higher than in the control (with WAS only) after 42 days of incubation. Although the lag phase period was longer in FD co-digestion (S/I = 0.5) than in FOG co-digestion (S/I = 0.5) under the same organic loading (gVS) and two times the COD loading, the daily methane production rate became higher after Day 15 in FD co-digestion. Significantly higher cumulative methane production (10.2%, p < 0.05) was obtained in FD co-digestion than in FOG co-digestion after 42-days. Microbial community analysis revealed higher levels of Geobacter in FD co-digestion, possibly suggesting a role for direct interspecies electron transfer (DIET) between Methanosaeta and Geobacter. This work provides fundamental insights supporting anaerobic co-digestion of FDs with WAS, demonstrating the advantages of FDs compared to FOG as co-substrate for enhanced biomethane recovery.
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Affiliation(s)
- Jiahou Hao
- College of Environmental Science and Engineering, Guilin University of Technology, Guangxi, 541006, China
| | - Francis L de Los Reyes Iii
- Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Xia He
- College of Environmental Science and Engineering, Guilin University of Technology, Guangxi, 541006, China.
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11
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Conversion of waste cooking oil into biogas: perspectives and limits. Appl Microbiol Biotechnol 2020; 104:2833-2856. [DOI: 10.1007/s00253-020-10431-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/24/2020] [Accepted: 02/03/2020] [Indexed: 10/25/2022]
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12
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Identification of novel potential acetate-oxidizing bacteria in thermophilic methanogenic chemostats by DNA stable isotope probing. Appl Microbiol Biotechnol 2019; 103:8631-8645. [DOI: 10.1007/s00253-019-10078-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [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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Zamorano-López N, Greses S, Aguado D, Seco A, Borrás L. Thermophilic anaerobic conversion of raw microalgae: Microbial community diversity in high solids retention systems. ALGAL RES 2019. [DOI: 10.1016/j.algal.2019.101533] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Acetotrophic Activity Facilitates Methanogenesis from LCFA at Low Temperatures: Screening from Mesophilic Inocula. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2019; 2019:1751783. [PMID: 31191117 PMCID: PMC6525847 DOI: 10.1155/2019/1751783] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 02/14/2019] [Accepted: 04/03/2019] [Indexed: 12/04/2022]
Abstract
The inoculum source plays a crucial role in the anaerobic treatment of wastewaters. Lipids are present in various wastewaters and have a high methanogenic potential, but their hydrolysis results in the production of long chain fatty acids (LCFAs) that are inhibitory to anaerobic microorganisms. Screening of inoculum for the anaerobic treatment of LCFA-containing wastewaters has been performed at mesophilic and thermophilic conditions. However, an evaluation of inocula for producing methane from LCFA-containing wastewater has not yet been conducted at low temperatures and needs to be undertaken. In this study, three inocula (one granular sludge and two municipal digester sludges) were assessed for methane production from LCFA-containing synthetic dairy wastewater (SDW) at low temperatures (10 and 20°C). A methane yield (based on mL-CH4/g-CODadded) of 86-65% with acetate and 45-20% with SDW was achieved within 10 days using unacclimated granular sludge, whereas the municipal digester sludges produced methane only at 20°C but not at 10°C even after 200 days of incubation. The acetotrophic activity in the inoculum was found to be crucial for methane production from LCFA at low temperatures, highlighting the role of Methanosaeta (acetoclastic archaea) at low temperatures. The presence of bacterial taxa from the family Syntrophaceae (Syntrophus and uncultured taxa) in the inoculum was found to be important for methane production from SDW at 10°C. This study suggests the evaluation of acetotrophic activity and the initial microbial community characteristics by high-throughput amplicon sequencing for selecting the inoculum for producing methane at low temperatures (up to 10°C) from lipid-containing wastewaters.
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Yamaguchi T, Nakamura S, Hatamoto M, Tamura E, Tanikawa D, Kawakami S, Nakamura A, Kato K, Nagano A, Yamaguchi T. A novel approach for toluene gas treatment using a downflow hanging sponge reactor. Appl Microbiol Biotechnol 2018; 102:5625-5634. [DOI: 10.1007/s00253-018-8933-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 03/06/2018] [Accepted: 03/09/2018] [Indexed: 10/17/2022]
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Jia Y, Ng SK, Lu H, Cai M, Lee PKH. Genome-centric metatranscriptomes and ecological roles of the active microbial populations during cellulosic biomass anaerobic digestion. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:117. [PMID: 29713376 PMCID: PMC5911951 DOI: 10.1186/s13068-018-1121-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/16/2018] [Indexed: 05/13/2023]
Abstract
BACKGROUND Although anaerobic digestion for biogas production is used worldwide in treatment processes to recover energy from carbon-rich waste such as cellulosic biomass, the activities and interactions among the microbial populations that perform anaerobic digestion deserve further investigations, especially at the population genome level. To understand the cellulosic biomass-degrading potentials in two full-scale digesters, this study examined five methanogenic enrichment cultures derived from the digesters that anaerobically digested cellulose or xylan for more than 2 years under 35 or 55 °C conditions. RESULTS Metagenomics and metatranscriptomics were used to capture the active microbial populations in each enrichment culture and reconstruct their meta-metabolic network and ecological roles. 107 population genomes were reconstructed from the five enrichment cultures using a differential coverage binning approach, of which only a subset was highly transcribed in the metatranscriptomes. Phylogenetic and functional convergence of communities by enrichment condition and phase of fermentation was observed for the highly transcribed populations in the metatranscriptomes. In the 35 °C cultures grown on cellulose, Clostridium cellulolyticum-related and Ruminococcus-related bacteria were identified as major hydrolyzers and primary fermenters in the early growth phase, while Clostridium leptum-related bacteria were major secondary fermenters and potential fatty acid scavengers in the late growth phase. While the meta-metabolism and trophic roles of the cultures were similar, the bacterial populations performing each function were distinct between the enrichment conditions. CONCLUSIONS Overall, a population genome-centric view of the meta-metabolism and functional roles of key active players in anaerobic digestion of cellulosic biomass was obtained. This study represents a major step forward towards understanding the microbial functions and interactions at population genome level during the microbial conversion of lignocellulosic biomass to methane. The knowledge of this study can facilitate development of potential biomarkers and rational design of the microbiome in anaerobic digesters.
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Affiliation(s)
- Yangyang Jia
- B5423-AC1, School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
| | - Siu-Kin Ng
- B5423-AC1, School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
| | - Hongyuan Lu
- B5423-AC1, School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
| | - Mingwei Cai
- B5423-AC1, School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
| | - Patrick K. H. Lee
- B5423-AC1, School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
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Amha YM, Anwar MZ, Brower A, Jacobsen CS, Stadler LB, Webster TM, Smith AL. Inhibition of anaerobic digestion processes: Applications of molecular tools. BIORESOURCE TECHNOLOGY 2018; 247:999-1014. [PMID: 28918349 DOI: 10.1016/j.biortech.2017.08.210] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 08/30/2017] [Accepted: 08/31/2017] [Indexed: 05/25/2023]
Abstract
Inhibition of anaerobic digestion (AD) due to perturbation caused by substrate composition and/or operating conditions can significantly reduce performance. Such perturbations could be limited by elucidating microbial community response to inhibitors and devising strategies to increase community resilience. To this end, advanced molecular methods are increasingly being applied to study the AD microbiome, a diverse community of microbial populations with complex interactions. This literature review of AD inhibition studies indicates that inhibitory concentrations are highly variable, likely stemming from differences in community structure or activity profile and previous exposure to inhibitors. More recent molecular methods such as 'omics' tools, substrate mapping, and real-time sequencing are helping to unravel the complexity of AD inhibition by elucidating physiological and ecological significance of key microbial populations. The AD community must strive towards developing predictive abilities to avoid system failure (e.g., real-time tracking of an indicator species) to improve resilience of AD systems.
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Affiliation(s)
- Yamrot M Amha
- Astani Department of Civil and Environmental Engineering, University of Southern California, 3620 South Vermont Avenue, Los Angeles, CA 90089, USA
| | - Muhammad Zohaib Anwar
- mBioInform ApS, Ole Maaloes Vej 3, 2200 Copenhagen N, Denmark; Department of Environmental Sciences, Aarhus University, Frederiksborgvej, 399, 4000 Roskilde, Denmark
| | - Andrew Brower
- Department of Civil and Environmental Engineering, Rice University, 6100 Main Street, TX 77005, USA
| | - Carsten S Jacobsen
- mBioInform ApS, Ole Maaloes Vej 3, 2200 Copenhagen N, Denmark; Department of Environmental Sciences, Aarhus University, Frederiksborgvej, 399, 4000 Roskilde, Denmark
| | - Lauren B Stadler
- Department of Civil and Environmental Engineering, Rice University, 6100 Main Street, TX 77005, USA
| | - Tara M Webster
- Soil and Crop Sciences Section, Cornell University, 306 Tower Road, Ithaca, NY 14853, USA
| | - Adam L Smith
- Astani Department of Civil and Environmental Engineering, University of Southern California, 3620 South Vermont Avenue, Los Angeles, CA 90089, USA.
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Amha YM, Sinha P, Lagman J, Gregori M, Smith AL. Elucidating microbial community adaptation to anaerobic co-digestion of fats, oils, and grease and food waste. WATER RESEARCH 2017; 123:277-289. [PMID: 28672212 DOI: 10.1016/j.watres.2017.06.065] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 06/22/2017] [Accepted: 06/22/2017] [Indexed: 06/07/2023]
Abstract
Despite growing interest in co-digestion and demonstrated process improvements (e.g., enhanced stability and biogas production), few studies have evaluated how co-digestion impacts the anaerobic digestion (AD) microbiome. Three sequential bench-scale respirometry experiments were conducted at thermophilic temperature (50 °C) with various combinations of primary sludge (PS); thickened waste activated sludge (TWAS); fats, oils, and grease (FOG); and food waste (FW). Two additional runs were then performed to evaluate microbial inhibition at higher organic fractions of FOG (30-60% volatile solids loading (VSL; v/v)). Co-digestion of PS, TWAS, FOG, and FW resulted in a 26% increase in methane production relative to digestion of PS and TWAS. A substantial lag time was observed in biogas production for vessels with FOG addition that decreased by more than half in later runs, likely due to adaptation of the microbial community. 30% FOG with 10% FW showed the highest increase in methane production, increasing 53% compared to digestion of PS and TWAS. FOG addition above 50% VSL was found to be inhibitory with and without FW addition and resulted in volatile fatty acid (VFA) accumulation. Methane production was linked with high relative activity and abundance of syntrophic fatty-acid oxidizers alongside hydrogenotrophic methanogens, signaling the importance of interspecies interactions in AD. Specifically, relative activity of Syntrophomonas was significantly correlated with methane production. Further, methane production increased over subsequent runs along with methyl coenzyme M reductase (mcrA) gene expression, a functional gene in methanogens, suggesting temporal adaptation of the microbial community to co-digestion substrate mixtures. The study demonstrated the benefits of co-digestion in terms of performance enhancement and enrichment of key active microbial populations.
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Affiliation(s)
- Yamrot M Amha
- Astani Department of Civil and Environmental Engineering, University of Southern California, 3620 South Vermont Avenue, Los Angeles, CA 90089, USA
| | - Pooja Sinha
- Astani Department of Civil and Environmental Engineering, University of Southern California, 3620 South Vermont Avenue, Los Angeles, CA 90089, USA
| | - Jewls Lagman
- Astani Department of Civil and Environmental Engineering, University of Southern California, 3620 South Vermont Avenue, Los Angeles, CA 90089, USA
| | - Matt Gregori
- Divert, Inc., 23 Bradford Street, Concord, MA 01742, USA; Southern California Gas Company, 555 West Fifth Street, Los Angeles, CA 90013, USA
| | - Adam L Smith
- Astani Department of Civil and Environmental Engineering, University of Southern California, 3620 South Vermont Avenue, Los Angeles, CA 90089, USA.
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19
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Methanotrophic community composition based on pmoA genes in dissolved methane recovery and biological oxidation closed downflow hanging sponge reactors. Biochem Eng J 2017. [DOI: 10.1016/j.bej.2017.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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20
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Kawai M, Nagao N, Kawasaki N, Imai A, Toda T. Improvement of COD removal by controlling the substrate degradability during the anaerobic digestion of recalcitrant wastewater. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2016; 181:838-846. [PMID: 27449962 DOI: 10.1016/j.jenvman.2016.06.057] [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: 03/09/2016] [Revised: 05/28/2016] [Accepted: 06/26/2016] [Indexed: 06/06/2023]
Abstract
The recalcitrant landfill leachate was anaerobically digested at various mixing ratios with labile synthetic wastewater to evaluate the degradation properties of recalcitrant wastewater. The proportion of leachate to the digestion system was increased in three equal steps, starting from 0% to 100%, and later decreased back to 0% with the same steps. The chemical oxygen demand (COD) for organic carbon and other components were calculated by analyzing the COD and dissolved organic carbon (DOC), and the removal efficiencies of COD carbon and COD others were evaluated separately. The degradation properties of COD carbon and COD others shifted owing to changing of substrate degradability, and the removal efficiencies of COD carbon and COD others were improved after supplying 100% recalcitrant wastewater. The UV absorptive property and total organic carbon (TOC) of each molecular size using high performance liquid chromatography (HPLC)-size exclusion chromatography (SEC) with UVA and TOC detectors were also investigated, and the degradability of different molecular sizes was determined. Although the SEC system detected extracellular polymeric substances (EPS), which are produced by microbes in stressful environments, during early stages of the experiment, EPS were not detected after feeding 100% recalcitrant wastewater. These results suggest that the microbes had acclimatized to the recalcitrant wastewater degradation. The high removal rates of both COD carbon and COD others were sustained when the proportion of labile wastewater in the substrate was 33%, indicating that the effective removal of recalcitrant COD might be controlled by changing the substrate's degradability.
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Affiliation(s)
- Minako Kawai
- Faculty of Science and Engineering, Soka University, 1-236 Tangi-cho Hachioji, Tokyo, Japan; Asian People's Exchange, Inoue Building, Negishi 1-5-12, Taitou-ku, Tokyo, 110-0003, Japan.
| | - Norio Nagao
- Institute of Bioscience, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor Darul Ehsan, Malaysia
| | - Nobuyuki Kawasaki
- Faculty of Sciences and Biotechnology, Universiti Selangor, 45600, Bestari Jaya, Selangor, Malaysia; National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Akio Imai
- National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Tatsuki Toda
- Faculty of Science and Engineering, Soka University, 1-236 Tangi-cho Hachioji, Tokyo, Japan
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21
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Cho SK, Kim DH, Quince C, Im WT, Oh SE, Shin SG. Low-strength ultrasonication positively affects methanogenic granules toward higher AD performance: Implications from microbial community shift. ULTRASONICS SONOCHEMISTRY 2016; 32:198-203. [PMID: 27150761 DOI: 10.1016/j.ultsonch.2016.03.010] [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: 01/22/2016] [Revised: 03/08/2016] [Accepted: 03/08/2016] [Indexed: 06/05/2023]
Abstract
To elucidate the enhanced methane yield from organic wastes, the effects of low-strength ultrasonication on the microbial community structures in upflow anaerobic sludge blanket reactors were for the first time analyzed using pyrosequencing. Interestingly, a more even microbial community was observed in the ultrasonicated granules than in the control, which could compensate for the decreased richness and resulted in comparable (archaea) or even higher (bacteria) diversity. The ultrasonicated granules contained higher levels of δ-Proteobacteria, of which many are reportedly potential syntrophs, as well as methanogenic genera Methanosaeta, Methanotorris, and Methanococcus. The increased presence of syntrophic bacteria with their methanogenic partners was discussed with respect to hydrogen flux; their selective proliferation seems to be responsible for the enhanced anaerobic performance. This study is the first research shedding light on the novel function of low-strength ultrasound shifting the microbial structure towards better biogas production performance, and will facilitate application of low-strength ultrasound to other bioprocesses.
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Affiliation(s)
- Si-Kyung Cho
- Department of Biological and Environmental Science, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang, Gyeonggi-do, Republic of Korea
| | - Dong-Hoon Kim
- Department of Civil Engineering, Inha University, 100 Inha-ro, Nam-gu, Incheon, Republic of Korea
| | | | - Wan-Taek Im
- Department of Biotechnology, Hankyong National University, 327 Chungang-no, Anseong, Gyeonggi-do, Republic of Korea
| | - Sae-Eun Oh
- Department of Environmental Engineering, Hanbat National University, San 16-1, Duckmyoung-dong, Yuseong-gu, Daejeon, Republic of Korea
| | - Seung Gu Shin
- School of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Pohang, Gyeongbuk, Republic of Korea.
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22
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Treu L, Campanaro S, Kougias PG, Zhu X, Angelidaki I. Untangling the Effect of Fatty Acid Addition at Species Level Revealed Different Transcriptional Responses of the Biogas Microbial Community Members. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:6079-90. [PMID: 27154312 DOI: 10.1021/acs.est.6b00296] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In the present study, RNA-sequencing was used to elucidate the change of anaerobic digestion metatranscriptome after long chain fatty acids (oleate) exposure. To explore the general transcriptional behavior of the microbiome, the analysis was first performed on shotgun reads without considering a reference metagenome. As a second step, RNA reads were aligned on the genes encoded by the microbial community, revealing the expression of more than 51 000 different transcripts. The present study is the first research which was able to dissect the transcriptional behavior at a single species level by considering the 106 microbial genomes previously identified. The exploration of the metabolic pathways confirmed the importance of Syntrophomonas species in fatty acids degradation, and also highlighted the presence of protective mechanisms toward the long chain fatty acid effects in bacteria belonging to Clostridiales, Rykenellaceae, and in species of the genera Halothermothrix and Anaerobaculum. Additionally, an interesting transcriptional activation of the chemotaxis genes was evidenced in seven species belonging to Clostridia, Halothermothrix, and Tepidanaerobacter. Surprisingly, methanogens revealed a very versatile behavior different from each other, even among similar species of the Methanoculleus genus, while a strong increase of the expression level in Methanosarcina sp. was evidenced after oleate addition.
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Affiliation(s)
- Laura Treu
- Department of Environmental Engineering, Technical University of Denmark , 2800 Kgs. Lyngby, Denmark
- Department of Agronomy Food Natural Resources Animals and Environment (DAFNAE), University of Padova , Viale dell'Università 16, Legnaro, PD 35020, Italy
| | - Stefano Campanaro
- Department of Biology, University of Padova , Via U. Bassi 58/b, 35121, Padova Italy
| | - Panagiotis G Kougias
- Department of Environmental Engineering, Technical University of Denmark , 2800 Kgs. Lyngby, Denmark
| | - Xinyu Zhu
- Department of Environmental Engineering, Technical University of Denmark , 2800 Kgs. Lyngby, Denmark
| | - Irini Angelidaki
- Department of Environmental Engineering, Technical University of Denmark , 2800 Kgs. Lyngby, Denmark
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23
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Perez-Garcia O, Lear G, Singhal N. Metabolic Network Modeling of Microbial Interactions in Natural and Engineered Environmental Systems. Front Microbiol 2016; 7:673. [PMID: 27242701 PMCID: PMC4870247 DOI: 10.3389/fmicb.2016.00673] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/25/2016] [Indexed: 12/14/2022] Open
Abstract
We review approaches to characterize metabolic interactions within microbial communities using Stoichiometric Metabolic Network (SMN) models for applications in environmental and industrial biotechnology. SMN models are computational tools used to evaluate the metabolic engineering potential of various organisms. They have successfully been applied to design and optimize the microbial production of antibiotics, alcohols and amino acids by single strains. To date however, such models have been rarely applied to analyze and control the metabolism of more complex microbial communities. This is largely attributed to the diversity of microbial community functions, metabolisms, and interactions. Here, we firstly review different types of microbial interaction and describe their relevance for natural and engineered environmental processes. Next, we provide a general description of the essential methods of the SMN modeling workflow including the steps of network reconstruction, simulation through Flux Balance Analysis (FBA), experimental data gathering, and model calibration. Then we broadly describe and compare four approaches to model microbial interactions using metabolic networks, i.e., (i) lumped networks, (ii) compartment per guild networks, (iii) bi-level optimization simulations, and (iv) dynamic-SMN methods. These approaches can be used to integrate and analyze diverse microbial physiology, ecology and molecular community data. All of them (except the lumped approach) are suitable for incorporating species abundance data but so far they have been used only to model simple communities of two to eight different species. Interactions based on substrate exchange and competition can be directly modeled using the above approaches. However, interactions based on metabolic feedbacks, such as product inhibition and synthropy require extensions to current models, incorporating gene regulation and compounding accumulation mechanisms. SMN models of microbial interactions can be used to analyze complex “omics” data and to infer and optimize metabolic processes. Thereby, SMN models are suitable to capitalize on advances in high-throughput molecular and metabolic data generation. SMN models are starting to be applied to describe microbial interactions during wastewater treatment, in-situ bioremediation, microalgae blooms methanogenic fermentation, and bioplastic production. Despite their current challenges, we envisage that SMN models have future potential for the design and development of novel growth media, biochemical pathways and synthetic microbial associations.
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Affiliation(s)
- Octavio Perez-Garcia
- Department of Civil and Environmental Engineering, University of Auckland Auckland, New Zealand
| | - Gavin Lear
- School of Biological Sciences, The University of Auckland Auckland, New Zealand
| | - Naresh Singhal
- Department of Civil and Environmental Engineering, University of Auckland Auckland, New Zealand
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24
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Regueiro L, Spirito CM, Usack JG, Hospodsky D, Werner JJ, Angenent LT. Comparing the inhibitory thresholds of dairy manure co-digesters after prolonged acclimation periods: Part 2--correlations between microbiomes and environment. WATER RESEARCH 2015; 87:458-66. [PMID: 26071316 DOI: 10.1016/j.watres.2015.05.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 05/09/2015] [Accepted: 05/23/2015] [Indexed: 05/13/2023]
Abstract
Here, we studied the microbiome succession and time-scale variability of four mesophilic anaerobic reactors in a co-digestion study with the objective to find links between changing environmental conditions and the microbiome composition. The changing environmental conditions were ensured by gradual increases in loading rates and mixing ratios of three co-substrates with a constant manure-feeding scheme during an operating period longer than 900 days. Each co-substrate (i.e., alkaline hydrolysate, food waste, and glycerol) was co-digested separately. High throughput 16S rRNA gene sequencing was used to examine the microbiome succession. The alkaline hydrolysate reactor microbiome shifted and adapted to high concentrations of free ammonia, total volatile fatty acids, and potassium to maintain its function. The addition of food waste and glycerol as co-substrates also led to microbiome changes, but to a lesser extent, especially in the case of the glycerol reactor microbiome. The divergence of the food waste reactor microbiome was primarily linked to increasing free ammonia levels in the reactor; though, these levels remained below previously reported inhibitory levels for acclimated biomass. The glycerol reactor microbiome succession included an increase in Syntrophomonadaceae family members, which have previously been linked to long-chain fatty acid degradation. The glycerol reactor exhibited rapid failure and limited adaptation at the end of the study.
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Affiliation(s)
- Leticia Regueiro
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA; Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, Rúa Lope Gómez de Marzoa s/n, E-15782 Santiago de Compostela, Spain
| | - Catherine M Spirito
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Joseph G Usack
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Denina Hospodsky
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | | | - Largus T Angenent
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA.
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25
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Aida AA, Kuroda K, Yamamoto M, Nakamura A, Hatamoto M, Yamaguchi T. Diversity Profile of Microbes Associated with Anaerobic Sulfur Oxidation in an Upflow Anaerobic Sludge Blanket Reactor Treating Municipal Sewage. Microbes Environ 2015; 30:157-63. [PMID: 25817585 PMCID: PMC4462926 DOI: 10.1264/jsme2.me14105] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We herein analyzed the diversity of microbes involved in anaerobic sulfur oxidation in an upflow anaerobic sludge blanket (UASB) reactor used for treating municipal sewage under low-temperature conditions. Anaerobic sulfur oxidation occurred in the absence of oxygen, with nitrite and nitrate as electron acceptors; however, reactor performance parameters demonstrated that anaerobic conditions were maintained. In order to gain insights into the underlying basis of anaerobic sulfur oxidation, the microbial diversity that exists in the UASB sludge was analyzed comprehensively to determine their identities and contribution to sulfur oxidation. Sludge samples were collected from the UASB reactor over a period of 2 years and used for bacterial 16S rRNA gene-based terminal restriction fragment length polymorphism (T-RFLP) and next-generation sequencing analyses. T-RFLP and sequencing results both showed that microbial community patterns changed markedly from day 537 onwards. Bacteria belonging to the genus Desulforhabdus within the phylum Proteobacteria and uncultured bacteria within the phylum Fusobacteria were the main groups observed during the period of anaerobic sulfur oxidation. Their abundance correlated with temperature, suggesting that these bacterial groups played roles in anaerobic sulfur oxidation in UASB reactors.
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Affiliation(s)
- Azrina A Aida
- Department of Environmental Systems Engineering, Nagaoka University of Technology
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26
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Ziels RM, Beck DAC, Martí M, Gough HL, Stensel HD, Svensson BH. Monitoring the dynamics of syntrophic β-oxidizing bacteria during anaerobic degradation of oleic acid by quantitative PCR. FEMS Microbiol Ecol 2015; 91:fiv028. [PMID: 25873606 DOI: 10.1093/femsec/fiv028] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2015] [Indexed: 11/12/2022] Open
Abstract
The ecophysiology of long-chain fatty acid-degrading syntrophic β-oxidizing bacteria has been poorly understood due to a lack of quantitative abundance data. Here, TaqMan quantitative PCR (qPCR) assays targeting the 16S rRNA gene of the known mesophilic syntrophic β-oxidizing bacterial genera Syntrophomonas and Syntrophus were developed and validated. Microbial community dynamics were followed using qPCR and Illumina-based high-throughput amplicon sequencing in triplicate methanogenic bioreactors subjected to five consecutive batch feedings of oleic acid. With repeated oleic acid feeding, the initial specific methane production rate significantly increased along with the relative abundances of Syntrophomonas and methanogenic archaea in the bioreactor communities. The novel qPCR assays showed that Syntrophomonas increased from 7 to 31% of the bacterial community 16S rRNA gene concentration, whereas that of Syntrophus decreased from 0.02 to less than 0.005%. High-throughput amplicon sequencing also revealed that Syntrophomonas became the dominant genus within the bioreactor microbiomes. These results suggest that increased specific mineralization rates of oleic acid were attributed to quantitative shifts within the microbial communities toward higher abundances of syntrophic β-oxidizing bacteria and methanogenic archaea. The novel qPCR assays targeting syntrophic β-oxidizing bacteria may thus serve as monitoring tools to indicate the fatty acid β-oxidization potential of anaerobic digester communities.
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Affiliation(s)
- Ryan M Ziels
- Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, WA 98195, USA
| | - David A C Beck
- eScience Institute, University of Washington, Box 355014, Seattle, WA 98195, USA Department of Chemical Engineering, University of Washington, Box 355014, Seattle, WA 98195, USA
| | - Magalí Martí
- Department of Thematic Studies-Environmental Change, Linköping University, SE-581 83 Linköping, Sweden
| | - Heidi L Gough
- Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, WA 98195, USA
| | - H David Stensel
- Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, WA 98195, USA
| | - Bo H Svensson
- Department of Thematic Studies-Environmental Change, Linköping University, SE-581 83 Linköping, Sweden
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He X, Zhang Q, Cooney MJ, Yan T. Biodegradation of fat, oil and grease (FOG) deposits under various redox conditions relevant to sewer environment. Appl Microbiol Biotechnol 2015; 99:6059-68. [PMID: 25715780 DOI: 10.1007/s00253-015-6457-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 01/30/2015] [Accepted: 02/01/2015] [Indexed: 10/24/2022]
Abstract
Fat, oil and, grease (FOG) deposits are one primary cause of sanitary sewer overflows (SSOs). While numerous studies have examined the formation of FOG deposits in sewer pipes, little is known about their biodegradation under sewer environments. In this study, FOG deposit biodegradation potential was determined by studying the biodegradation of calcium palmitate in laboratory under aerobic, nitrate-reducing, sulfate-reducing, and methanogenic conditions. Over 110 days of observation, calcium palmitate was biodegraded to CO2 under aerobic and nitrate-reducing conditions. An approximate 13 times higher CO2 production rate was observed under aerobic condition than under nitrate-reducing condition. Under sulfate-reducing condition, calcium palmitate was recalcitrant to biodegradation as evidenced by small reduction in sulfate. No evidence was found to support calcium palmitate degradation under methanogenic condition in the simulated sewer environment. Dominant microbial populations in the aerobic and nitrate-reducing microcosms were identified by Illumina seqeuncing, which may contain the capability to degrade calcium palmitate under both aerobic and nitrate-reducing conditions. Further study on these populations and their functional genes could shed more light on this microbial process and eventually help develop engineering solutions for SSOs control in the future.
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Affiliation(s)
- Xia He
- Department of Civil and Environmental Engineering, University of Hawaii at Manoa, Honolulu, HI, 96822, USA
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28
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Miłobędzka A, Muszyński A. Population dynamics of filamentous bacteria identified in Polish full-scale wastewater treatment plants with nutrients removal. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2015; 71:675-684. [PMID: 25768213 DOI: 10.2166/wst.2014.512] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A comprehensive study of the identity and population dynamics of filamentous bacteria in five Polish full-scale municipal wastewater treatment plants (WWTPs) with nutrients removal had been carried out for 2 years. A quantitative culture-independent, molecular method - fluorescence in situ hybridization - was applied to evaluate the structure of different filamentous bacteria populations and their temporal variations. Activated sludge was examined for the abundance of 11 groups of filamentous bacteria. On average, filaments constituted 28% of all bacteria. All samples presented a low diversity of probe-defined filamentous bacteria, usually with significant domination of Chloroflexi (with distinction to types 1851, 0803 and others) and/or Microthrix (14% and 7% of EUBmix, respectively). Haliscomenobacter hydrossis, Mycolata, Skermania piniformis and TM7 were less abundant, whereas Curvibacter, Thiothrix/021N and family Gordonia have not been detected in any of the samples. The tested WWTPs showed similarity among species found and differences in their abundance. The composition of filamentous populations was rather stable in each plant and similar to those found in other European countries. Little differences between plants were shown by multivariate analysis of variance in terms of Chloroflexi and Microthrix. No significant general correlations have been found with Pearson product-moment correlation coefficient and Spearman's rank correlation coefficient. Medium correlation strength between the presence of different filaments was recorded only for Microthrix and Skermania piniformis. Deleterious effect on settling properties of sludge (measured as sludge volume index) was found only for abundance of Microthrix; a strong linear correlation was recorded between them. However, no other correlations with wastewater and operational data were revealed.
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Affiliation(s)
- A Miłobędzka
- Faculty of Environmental Engineering, Department of Biology, Warsaw University of Technology, Nowowiejska 20, Warsaw 00-653, Poland E-mail:
| | - A Muszyński
- Faculty of Environmental Engineering, Department of Biology, Warsaw University of Technology, Nowowiejska 20, Warsaw 00-653, Poland E-mail:
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Aida AA, Hatamoto M, Yamamoto M, Ono S, Nakamura A, Takahashi M, Yamaguchi T. Molecular characterization of anaerobic sulfur-oxidizing microbial communities in up-flow anaerobic sludge blanket reactor treating municipal sewage. J Biosci Bioeng 2014; 118:540-5. [DOI: 10.1016/j.jbiosc.2014.04.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 04/01/2014] [Accepted: 04/16/2014] [Indexed: 10/25/2022]
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30
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Hwang OH, Raveendar S, Kim YJ, Kim JH, Choi JW, Kim TH, Choi DY, Jeon CO, Cho SB, Lee KT. Deodorization of pig slurry and characterization of bacterial diversity using 16S rDNA sequence analysis. J Microbiol 2014; 52:918-29. [PMID: 25359269 DOI: 10.1007/s12275-014-4251-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 09/01/2014] [Accepted: 09/05/2014] [Indexed: 02/05/2023]
Abstract
The concentration of major odor-causing compounds including phenols, indoles, short-chain fatty acids (SCFAs) and branched chain fatty acids (BCFAs) in response to the addition of powdered horse radish (PHR) and spent mushroom compost (SMC) was compared with control non-treated slurry (CNS) samples. A total of 97,465 rDNAs sequence reads were generated from three different samples (CNS, n = 2; PHR, n = 3; SMC, n = 3) using bar-coded pyrosequencing. The number of operational taxonomic units (OTUs) was lower in the PHR slurry compared with the other samples. A total of 11 phyla were observed in the slurry samples, while the phylogenetic analysis revealed that the slurry microbiome predominantly comprised members of the Bacteroidetes, Firmicutes, and Proteobacteria phyla. The rarefaction analysis showed the bacterial species richness varied among the treated samples. Overall, at the OTU level, 2,558 individual genera were classified, 276 genera were found among the three samples, and 1,832 additional genera were identified in the individual samples. A principal component analysis revealed the differences in microbial communities among the CNS, PHR, and SMC pig slurries. Correlation of the bacterial community structure with the Kyoto Encyclopedia of Genes and Genomes (KEGG) predicted pathways showed that the treatments altered the metabolic capabilities of the slurry microbiota. Overall, these results demonstrated that the PHR and S MC treatments significantly reduced the malodor compounds in pig slurry (P < 0.05).
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Affiliation(s)
- Ok-Hwa Hwang
- National Institute of Animal Science, Rural Development Administration, Suwon, 441-706, Republic of Korea
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31
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Hatamoto M, Kaneshige M, Nakamura A, Yamaguchi T. Bacteroides luti sp. nov., an anaerobic, cellulolytic and xylanolytic bacterium isolated from methanogenic sludge. Int J Syst Evol Microbiol 2014; 64:1770-1774. [DOI: 10.1099/ijs.0.056630-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A mesophilic, anaerobic, cellulolytic and xylanolytic strain, UasXn-3T, was isolated from anaerobic granular sludge in a mesophilic upflow anaerobic sludge blanket reactor, which was used to treat municipal sewage. The cells were Gram-stain-negative, non-motile, and non-spore-forming rods. The optimal temperature for growth was 37–40 °C and the optimal pH for growth was pH 6.5–7.0. Strain UasXn-3T could grow on several polysaccharides and sugars, including cellulose, cellobiose, xylan, xylose, glucose, fructose, arabinose, mannose, raffinose, trehalose and starch. The DNA G+C content was 44.4 mol%. On the basis of comparative 16S rRNA gene sequence analysis, strain UasXn-3T was identified as a member of the genus
Bacteroides
and most closely related to
Bacteroides oleiciplenus
,
B. intestinalis
,
B. cellulosilyticus
and
B. graminisolvens
(sequence similarities of 91.3–91.6 %). Since the genetic and phenotypic properties suggest that strain UasXn-3T represents a novel species, we propose the name Bacteroides luti sp. nov. The type strain is UasXn-3T ( = JCM 19020T = DSM 26991T).
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Affiliation(s)
- Masashi Hatamoto
- Department of Environmental Systems Engineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Masami Kaneshige
- Department of Environmental Systems Engineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Akinobu Nakamura
- Department of Environmental Systems Engineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Takashi Yamaguchi
- Department of Environmental Systems Engineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
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32
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Ramos DT, da Silva MLB, Nossa CW, Alvarez PJJ, Corseuil HX. Assessment of microbial communities associated with fermentative-methanogenic biodegradation of aromatic hydrocarbons in groundwater contaminated with a biodiesel blend (B20). Biodegradation 2014; 25:681-91. [PMID: 24748449 DOI: 10.1007/s10532-014-9691-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 04/09/2014] [Indexed: 11/25/2022]
Abstract
A controlled field experiment was conducted to assess the potential for fermentative-methanogenic biostimulation (by ammonium-acetate injection) to enhance biodegradation of benzene, toluene, ethylbenzene and xylenes (BTEX) as well as polycyclic aromatic hydrocarbons (PAHs) in groundwater contaminated with biodiesel B20 (20:80 v/v soybean biodiesel and diesel). Changes in microbial community structure were assessed by pyrosequencing 16S rRNA analyses. BTEX and PAH removal began 0.7 year following the release, concomitantly with the increase in the relative abundance of Desulfitobacterium and Geobacter spp. (from 5 to 52.7 % and 15.8 to 37.3 % of total Bacteria 16S rRNA, respectively), which are known to anaerobically degrade hydrocarbons. The accumulation of anaerobic metabolites acetate and hydrogen that could hinder the thermodynamic feasibility of BTEX and PAH biotransformations under fermentative/methanogenic conditions was apparently alleviated by the growing predominance of Methanosarcina. This suggests the importance of microbial population shifts that enrich microorganisms capable of interacting syntrophically to enhance the feasibility of fermentative-methanogenic bioremediation of biodiesel blend releases.
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Affiliation(s)
- Débora Toledo Ramos
- Department of Sanitary and Environmental Engineering, Federal University of Santa Catarina, Florianópolis, SC, Brazil,
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33
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Sieber JR, Le HM, McInerney MJ. The importance of hydrogen and formate transfer for syntrophic fatty, aromatic and alicyclic metabolism. Environ Microbiol 2013; 16:177-88. [DOI: 10.1111/1462-2920.12269] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 08/14/2013] [Accepted: 08/26/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Jessica R. Sieber
- Department of Microbiology and Plant Biology; University of Oklahoma; Norman OK 73019 USA
| | - Huynh M. Le
- Department of Microbiology and Plant Biology; University of Oklahoma; Norman OK 73019 USA
| | - Michael J. McInerney
- Department of Microbiology and Plant Biology; University of Oklahoma; Norman OK 73019 USA
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34
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Zonta Z, Alves MM, Flotats X, Palatsi J. Modelling inhibitory effects of long chain fatty acids in the anaerobic digestion process. WATER RESEARCH 2013; 47:1369-80. [PMID: 23276428 DOI: 10.1016/j.watres.2012.12.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 12/03/2012] [Accepted: 12/05/2012] [Indexed: 05/26/2023]
Abstract
Mathematical modelling of anaerobic digestion process has been used to give new insights regarding dynamics of the long chain fatty acids (LCFA) inhibition. Previously published experimental data, including batch tests with clay mineral bentonite additions, were used for parameter identification. New kinetics were considered to describe the bio-physics of the inhibitory process, including: i) adsorption of LCFA over granular biomass and ii) specific LCFA substrate (saturated/unsaturated) and LCFA-degrading populations. Furthermore, iii) a new variable was introduced to describe the state of damage of the acetoclastic methanogens in order to account for the loss of cell-functionality (inhibition) induced by the adsorbed LCFAs. The proposed model modifications are state compatible and easy to be integrated into the International Water Association's Anaerobic Digestion Model N°1 (ADM1) framework. Practical identifiability of model parameters was assessed with a global sensitivity analysis, while calibration and model structure validation were performed on independent data sets. A reliable simulation of the LCFA-inhibition process can be achieved, if the model includes the description of the adsorptive nature of the LCFAs and the LCFA-damage over specific biomass. The importance of microbial population structure (saturated/unsaturated LCFA-degraders) and the high sensitivity of acetoclastic population to LCFA are evidenced, providing a plausible explanation of experimental based hypothesis.
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Affiliation(s)
- Z Zonta
- IRTA, GIRO Joint Research Unit IRTA-UPC, Torre Marimon, E-08140 Caldes de Montbui, Barcelona, Spain
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35
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Zhang C, Xiao G, Peng L, Su H, Tan T. The anaerobic co-digestion of food waste and cattle manure. BIORESOURCE TECHNOLOGY 2013; 129:170-176. [PMID: 23246757 DOI: 10.1016/j.biortech.2012.10.138] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 10/27/2012] [Accepted: 10/27/2012] [Indexed: 06/01/2023]
Abstract
This study assessed the anaerobic co-digestion of food waste and cattle manure, in order to identify the key parameters that determine the biogas and methane yield. Results of both batch and semi-continuous tests indicated that the total methane production is enhanced in co-digestion, with an optimum food waste (FM) to cattle manure (CM) ratio of 2. At this ratio, the total methane production in batch tests was enhanced by 41.1%, and the corresponding methane yield was 388 mL/g-VS. In the semi-continuous mode, the total methane production in co-digestion, at the organic loading rate (OLR) of 10 g-VSFW/L/d, increased by 55.2%, corresponding to the methane yield of 317 mL/g-VS. Addition of cattle manure enhanced the buffer capacity (created by NH4+ and VFAs), allowing high organic load without pH control. The C/N ratio and the higher biodegradation of lipids might be the main reasons for the biogas production improvement.
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Affiliation(s)
- Cunsheng Zhang
- Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing 100029, PR China
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36
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Tian Z, Chauliac D, Pullammanappallil P. Comparison of non-agitated and agitated batch, thermophilic anaerobic digestion of sugarbeet tailings. BIORESOURCE TECHNOLOGY 2013; 129:411-420. [PMID: 23262019 DOI: 10.1016/j.biortech.2012.11.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 11/06/2012] [Accepted: 11/11/2012] [Indexed: 06/01/2023]
Abstract
Sugar beet tailings were anaerobically digested at non-agitated and agitated conditions in identical thermophilic batch reactors. The average methane yield in the agitated digester was only 74% of that in the non-agitated digester. Ninety percent of the ultimate methane yield was produced in approximately 5 days in the non-agitated digester whereas it took 12 days in agitated digester. Even upon using an active inoculum from non-agitated digester the methane rate and yield was low in the agitated digester. On the other hand when the poorly performing inoculum from the agitated digester was transferred to the non-agitated digester, its activity was immediately enhanced. The non-agitated digester harbored a diverse microbial community with phylotypes Methanoculleus and Methanosarcina being dominant methanogens. Methanosaeta was the only methanogen detected in the agitated digester. It also contained a hydrogen-producing bacterial phylotype Petrotoga in high proportion which was not detected in the other digester.
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Affiliation(s)
- Zhuoli Tian
- Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL 32611, United States
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37
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Maphosa F, Lieten SH, Dinkla I, Stams AJ, Smidt H, Fennell DE. Ecogenomics of microbial communities in bioremediation of chlorinated contaminated sites. Front Microbiol 2012; 3:351. [PMID: 23060869 PMCID: PMC3462421 DOI: 10.3389/fmicb.2012.00351] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 09/12/2012] [Indexed: 11/29/2022] Open
Abstract
Organohalide compounds such as chloroethenes, chloroethanes, and polychlorinated benzenes are among the most significant pollutants in the world. These compounds are often found in contamination plumes with other pollutants such as solvents, pesticides, and petroleum derivatives. Microbial bioremediation of contaminated sites, has become commonplace whereby key processes involved in bioremediation include anaerobic degradation and transformation of these organohalides by organohalide respiring bacteria and also via hydrolytic, oxygenic, and reductive mechanisms by aerobic bacteria. Microbial ecogenomics has enabled us to not only study the microbiology involved in these complex processes but also develop tools to better monitor and assess these sites during bioremediation. Microbial ecogenomics have capitalized on recent advances in high-throughput and -output genomics technologies in combination with microbial physiology studies to address these complex bioremediation problems at a system level. Advances in environmental metagenomics, transcriptomics, and proteomics have provided insights into key genes and their regulation in the environment. They have also given us clues into microbial community structures, dynamics, and functions at contaminated sites. These techniques have not only aided us in understanding the lifestyles of common organohalide respirers, for example Dehalococcoides, Dehalobacter, and Desulfitobacterium, but also provided insights into novel and yet uncultured microorganisms found in organohalide respiring consortia. In this paper, we look at how ecogenomic studies have aided us to understand the microbial structures and functions in response to environmental stimuli such as the presence of chlorinated pollutants.
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Affiliation(s)
- Farai Maphosa
- Laboratory of Microbiology, Wageningen UniversityWageningen, Netherlands
| | | | | | - Alfons J. Stams
- Laboratory of Microbiology, Wageningen UniversityWageningen, Netherlands
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen UniversityWageningen, Netherlands
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38
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Methanogenic octadecene degradation by syntrophic enrichment culture from brackish sediments. Curr Microbiol 2012; 65:561-7. [PMID: 22842907 DOI: 10.1007/s00284-012-0195-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 06/21/2012] [Indexed: 10/28/2022]
Abstract
A microbial enrichment culture from brackish sediments was able to grow on octadec-1-ene (an unsaturated aliphatic hydrocarbon) as sole source of carbon and energy, under methanogenic conditions. Octadecene degradation is stopped either when bromoethanesulfonic acid, a selective inhibitor of methanogenesis is introduced, or when hydrogen is introduced. In the presence of bromoethanesulfonic acid, the degradation is restored by the addition of a hydrogenotrophic sulfate-reducing microorganism with sulfate. Results of molecular biodiversity, which revealed the presence of bacteria as well as of acetoclastic and hydrogenotrophic methanogens, are consistent with a syntrophic degradation involving Bacteria and Archaea. This is the first demonstration of syntrophic alkene degradation by microbial communities, showing that syntrophy is more widespread than we could have thought so far. These results highlight the need for a better understanding of microbial interactions and their role in the organic-matter degradation in polluted environments.
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39
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Sieber JR, McInerney MJ, Gunsalus RP. Genomic insights into syntrophy: the paradigm for anaerobic metabolic cooperation. Annu Rev Microbiol 2012; 66:429-52. [PMID: 22803797 DOI: 10.1146/annurev-micro-090110-102844] [Citation(s) in RCA: 313] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Syntrophy is a tightly coupled mutualistic interaction between hydrogen-/formate-producing and hydrogen-/formate-using microorganisms that occurs throughout the microbial world. Syntrophy is essential for global carbon cycling, waste decomposition, and biofuel production. Reverse electron transfer, e.g., the input of energy to drive critical redox reactions, is a defining feature of syntrophy. Genomic analyses indicate multiple systems for reverse electron transfer, including ion-translocating ferredoxin:NAD(+) oxidoreductase and hydrogenases, two types of electron transfer flavoprotein:quinone oxidoreductases, and other quinone reactive complexes. Confurcating hydrogenases that couple the favorable production of hydrogen from reduced ferredoxin with the unfavorable production of hydrogen from NADH are present in almost all syntrophic metabolizers, implicating their critical role in syntrophy. Transcriptomic analysis shows upregulation of many genes without assigned functions in the syntrophic lifestyle. High-throughput technologies provide insight into the mechanisms used to establish and maintain syntrophic consortia and conserve energy from reactions that operate close to thermodynamic equilibrium.
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Affiliation(s)
- Jessica R Sieber
- Department of Botany and Microbiology, University of Oklahoma, Norman, 73019, USA.
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40
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Identification of glucose-fermenting bacteria in a full-scale enhanced biological phosphorus removal plant by stable isotope probing. Microbiology (Reading) 2012; 158:1818-1825. [DOI: 10.1099/mic.0.058818-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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41
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Key players and team play: anaerobic microbial communities in hydrocarbon-contaminated aquifers. Appl Microbiol Biotechnol 2012; 94:851-73. [PMID: 22476263 DOI: 10.1007/s00253-012-4025-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Revised: 03/13/2012] [Accepted: 03/14/2012] [Indexed: 02/06/2023]
Abstract
Biodegradation of anthropogenic pollutants in shallow aquifers is an important microbial ecosystem service which is mainly brought about by indigenous anaerobic microorganisms. For the management of contaminated sites, risk assessment and control of natural attenuation, the assessment of in situ biodegradation and the underlying microbial processes is essential. The development of novel molecular methods, "omics" approaches, and high-throughput techniques has revealed new insight into complex microbial communities and their functions in anoxic environmental systems. This review summarizes recent advances in the application of molecular methods to study anaerobic microbial communities in contaminated terrestrial subsurface ecosystems. We focus on current approaches to analyze composition, dynamics, and functional diversity of subsurface communities, to link identity to activity and metabolic function, and to identify the ecophysiological role of not yet cultured microbes and syntrophic consortia. We discuss recent molecular surveys of contaminated sites from an ecological viewpoint regarding degrader ecotypes, abiotic factors shaping anaerobic communities, and biotic interactions underpinning the importance of microbial cooperation for microbial ecosystem services such as contaminant degradation.
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42
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Baserba MG, Angelidaki I, Karakashev D. Effect of continuous oleate addition on microbial communities involved in anaerobic digestion process. BIORESOURCE TECHNOLOGY 2012; 106:74-81. [PMID: 22206917 DOI: 10.1016/j.biortech.2011.12.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 12/05/2011] [Accepted: 12/05/2011] [Indexed: 05/31/2023]
Abstract
In the present study, the microbial diversity in anaerobic reactors, continuously exposed to oleate, added to a manure reactor influent, was investigated. Relative changes in archaeal community were less remarkable in comparison to changes in bacterial community indicating that dominant archaeal composition remained relatively stable. Majority of the analyzed bacterial amplicons were phylogenetically affiliated with uncultured bacteria belonging to Firmicutes, Bacteroidetes, Proteobacteria and Thermotogae phyla. Bacterial community changes in response to oleate addition resulted in a less diverse bacterial consortium related to functional specialization of the species towards oleate degradation. For the archaeal domain, the sequences were affiliated within Euryarchaeota phylum with three major groups (Methanosarcina, Methanosaeta and Methanobacterium genera). Results obtained in this study deliver a comprehensive picture on oleate degrading microbial communities in high organic strength wastewater. The findings might be utilized for development of strategies for biogas production from lipid-riched wastes.
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Affiliation(s)
- Manel Garrido Baserba
- DTU Environment, Technical University of Denmark, Building 113, DK-2800 Kgs. Lyngby, Denmark.
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43
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Ahmad A, Ghufran R, Wahid ZA. Bioenergy from anaerobic degradation of lipids in palm oil mill effluent. REVIEWS IN ENVIRONMENTAL SCIENCE AND BIO/TECHNOLOGY 2011; 10:353-376. [DOI: 10.1007/s11157-011-9253-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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44
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Gray ND, Sherry A, Grant RJ, Rowan AK, Hubert CRJ, Callbeck CM, Aitken CM, Jones DM, Adams JJ, Larter SR, Head IM. The quantitative significance of Syntrophaceae and syntrophic partnerships in methanogenic degradation of crude oil alkanes. Environ Microbiol 2011; 13:2957-75. [PMID: 21914097 PMCID: PMC3258425 DOI: 10.1111/j.1462-2920.2011.02570.x] [Citation(s) in RCA: 192] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Libraries of 16S rRNA genes cloned from methanogenic oil degrading microcosms amended with North Sea crude oil and inoculated with estuarine sediment indicated that bacteria from the genera Smithella (Deltaproteobacteria, Syntrophaceace) and Marinobacter sp. (Gammaproteobacteria) were enriched during degradation. Growth yields and doubling times (36 days for both Smithella and Marinobacter) were determined using qPCR and quantitative data on alkanes, which were the predominant hydrocarbons degraded. The growth yield of the Smithella sp. [0.020 g(cell-C)/g(alkane-C)], assuming it utilized all alkanes removed was consistent with yields of bacteria that degrade hydrocarbons and other organic compounds in methanogenic consortia. Over 450 days of incubation predominance and exponential growth of Smithella was coincident with alkane removal and exponential accumulation of methane. This growth is consistent with Smithella's occurrence in near surface anoxic hydrocarbon degrading systems and their complete oxidation of crude oil alkanes to acetate and/or hydrogen in syntrophic partnership with methanogens in such systems. The calculated growth yield of the Marinobacter sp., assuming it grew on alkanes, was [0.0005 g(cell-C)/g(alkane-C)] suggesting that it played a minor role in alkane degradation. The dominant methanogens were hydrogenotrophs (Methanocalculus spp. from the Methanomicrobiales). Enrichment of hydrogen-oxidizing methanogens relative to acetoclastic methanogens was consistent with syntrophic acetate oxidation measured in methanogenic crude oil degrading enrichment cultures. qPCR of the Methanomicrobiales indicated growth characteristics consistent with measured rates of methane production and growth in partnership with Smithella.
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Affiliation(s)
- N D Gray
- School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
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45
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Tang YQ, Ji P, Hayashi J, Koike Y, Wu XL, Kida K. Characteristic microbial community of a dry thermophilic methanogenic digester: its long-term stability and change with feeding. Appl Microbiol Biotechnol 2011; 91:1447-61. [DOI: 10.1007/s00253-011-3479-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 06/28/2011] [Accepted: 07/13/2011] [Indexed: 11/28/2022]
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Struchtemeyer CG, Duncan KE, McInerney MJ. Evidence for syntrophic butyrate metabolism under sulfate-reducing conditions in a hydrocarbon-contaminated aquifer. FEMS Microbiol Ecol 2011; 76:289-300. [PMID: 21223338 DOI: 10.1111/j.1574-6941.2011.01046.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The importance of syntrophy in the degradation of butyrate in an aquifer where sulfate reduction was shown to be an important terminal electron-accepting process was assessed. Hydrocarbon-contaminated aquifer sediments coupled butyrate degradation to sulfate reduction and methane production. Butyrate degradation in methanogenic microcosms was inhibited by the addition of 2-bromoethanesulfonic acid, and was restored by the addition of 10 mM sulfate and a hydrogen- and formate-using sulfate reducer, but not by the addition of 10 mM sulfate alone. Molybdate addition inhibited butyrate degradation in sulfate-reducing microcosms. The addition of CO, which inhibits hydrogenases, to sulfate-reducing microcosms inhibited butyrate metabolism and caused the hydrogen partial pressure to increase to levels that would make syntrophic butyrate degradation via sulfate reduction energetically unfavorable (-5 to +3 kJ mol(-1) ). DNA extracted from the most probable number cultures and contaminated sediments contained sequences related to members of the families Syntrophomonadaceae and Syntrophaceae, whose members are known to syntrophically degrade fatty acids, as well as sequences related to uncultured Firmicutes, Desulfobulbaceae, Desulfobacteriaceae, and Desulfovibrionaceae. These data show that contaminated sediments degraded butyrate syntrophically coupled to methane production and sulfate reduction.
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Palatsi J, Viñas M, Guivernau M, Fernandez B, Flotats X. Anaerobic digestion of slaughterhouse waste: main process limitations and microbial community interactions. BIORESOURCE TECHNOLOGY 2011; 102:2219-2227. [PMID: 21030248 DOI: 10.1016/j.biortech.2010.09.121] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 09/21/2010] [Accepted: 09/29/2010] [Indexed: 05/30/2023]
Abstract
Fresh pig/cattle slaughterhouse waste mixtures, with different lipid-protein ratios, were characterized and their anaerobic biodegradability assessed in batch tests. The resultant methane potentials were high (270-300 L(CH4) kg(-1)(COD)) making them interesting substrates for the anaerobic digestion process. However, when increasing substrate concentrations in consecutive batch tests, up to 15 g(COD) kg(-1), a clear inhibitory process was monitored. Despite the reported severe inhibition, related to lipid content, the system was able to recover activity and successfully degrade the substrate. Furthermore, 16SrRNA gene-based DGGE results showed an enrichment of specialized microbial populations, such as β-oxidizing/proteolitic bacteria (Syntrophomonas sp., Coprothermobacter sp. and Anaerobaculum sp.), and syntrophic methanogens (Methanosarcina sp.). Consequently, the lipid concentration of substrate and the structure of the microbial community are the main limiting factors for a successful anaerobic treatment of fresh slaughterhouse waste.
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Affiliation(s)
- J Palatsi
- GIRO Technological Centre, Centre IRTA-UPC, Barcelona, Spain
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Enrichment and identification of methane-oxidizing bacteria by using down-flow hanging sponge bioreactors under low methane concentration. ANN MICROBIOL 2010. [DOI: 10.1007/s13213-010-0171-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Cuetos MJ, Gómez X, Otero M, Morán A. Anaerobic digestion and co-digestion of slaughterhouse waste (SHW): influence of heat and pressure pre-treatment in biogas yield. WASTE MANAGEMENT (NEW YORK, N.Y.) 2010; 30:1780-9. [PMID: 20176467 DOI: 10.1016/j.wasman.2010.01.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 01/11/2010] [Accepted: 01/28/2010] [Indexed: 05/08/2023]
Abstract
Mesophilic anaerobic digestion (34+/-1 degrees C) of pre-treated (for 20 min at 133 degrees C, >3 bar) slaughterhouse waste and its co-digestion with the organic fraction of municipal solid waste (OFMSW) have been assessed. Semi-continuously-fed digesters worked with a hydraulic retention time (HRT) of 36 d and organic loading rates (OLR) of 1.2 and 2.6 kg VS(feed)/m(3)d for digestion and co-digestion, respectively, with a previous acclimatization period in all cases. It was not possible to carry out an efficient treatment of hygienized waste, even less so when OFMSW was added as co-substrate. These digesters presented volatile fatty acids (VFA), long chain fatty acids (LCFA) and fats accumulation, leading to instability and inhibition of the degradation process. The aim of applying a heat and pressure pre-treatment to promote splitting of complex lipids and nitrogen-rich waste into simpler and more biodegradable constituents and to enhance biogas production was not successful. These results indicate that the temperature and the high pressure of the pre-treatment applied favoured the formation of compounds that are refractory to anaerobic digestion. The pre-treated slaughterhouse wastes and the final products of these systems were analyzed by FTIR and TGA. These tools verified the existence of complex nitrogen-containing polymers in the final effluents, confirming the formation of refractory compounds during pre-treatment.
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Affiliation(s)
- M J Cuetos
- Institute of Natural Resources (IRENA), University of León, Avda. de Portugal 41, 24071 León, Spain.
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Cavaleiro AJ, Sousa DZ, Alves MM. Methane production from oleate: assessing the bioaugmentation potential of Syntrophomonas zehnderi. WATER RESEARCH 2010; 44:4940-4947. [PMID: 20696454 DOI: 10.1016/j.watres.2010.07.039] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 07/02/2010] [Accepted: 07/13/2010] [Indexed: 05/29/2023]
Abstract
The potential for improving long-chain fatty acids (LCFA) conversion to methane was evaluated by bioaugmenting a non-acclimated anaerobic granular sludge with Syntrophomonas zehnderi. Batch bioaugmentation assays were performed with and without the solid microcarrier sepiolite, using 1 mM oleate as sole carbon and energy source. When S. zehnderi was added to the anaerobic sludge methane production from oleate was faster. High methane yields, i.e. 89 ± 5% and 72 ± 1%, were observed in bioaugmented assays in the absence and presence of sepiolite, respectively. Sepiolite stimulated a faster methane production from oleate and prevented the accumulation of acetate. Acetoclastic activity was affected by oleate in the absence of sepiolite, where methane production rate was 26% lower than in assays with microcarrier.
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Affiliation(s)
- A J Cavaleiro
- Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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