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McDaniel EA, Scarborough M, Mulat DG, Lin X, Sampara PS, Olson HM, Young RP, Eder EK, Attah IK, Markillie LM, Hoyt DW, Lipton MS, Hallam SJ, Ziels RM. Diverse electron carriers drive syntrophic interactions in an enriched anaerobic acetate-oxidizing consortium. THE ISME JOURNAL 2023; 17:2326-2339. [PMID: 37880541 PMCID: PMC10689502 DOI: 10.1038/s41396-023-01542-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/09/2023] [Accepted: 10/11/2023] [Indexed: 10/27/2023]
Abstract
In many anoxic environments, syntrophic acetate oxidation (SAO) is a key pathway mediating the conversion of acetate into methane through obligate cross-feeding interactions between SAO bacteria (SAOB) and methanogenic archaea. The SAO pathway is particularly important in engineered environments such as anaerobic digestion (AD) systems operating at thermophilic temperatures and/or with high ammonia. Despite the widespread importance of SAOB to the stability of the AD process, little is known about their in situ physiologies due to typically low biomass yields and resistance to isolation. Here, we performed a long-term (300-day) continuous enrichment of a thermophilic (55 °C) SAO community from a municipal AD system using acetate as the sole carbon source. Over 80% of the enriched bioreactor metagenome belonged to a three-member consortium, including an acetate-oxidizing bacterium affiliated with DTU068 encoding for carbon dioxide, hydrogen, and formate production, along with two methanogenic archaea affiliated with Methanothermobacter_A. Stable isotope probing was coupled with metaproteogenomics to quantify carbon flux into each community member during acetate conversion and inform metabolic reconstruction and genome-scale modeling. This effort revealed that the two Methanothermobacter_A species differed in their preferred electron donors, with one possessing the ability to grow on formate and the other only consuming hydrogen. A thermodynamic analysis suggested that the presence of the formate-consuming methanogen broadened the environmental conditions where ATP production from SAO was favorable. Collectively, these results highlight how flexibility in electron partitioning during SAO likely governs community structure and fitness through thermodynamic-driven mutualism, shedding valuable insights into the metabolic underpinnings of this key functional group within methanogenic ecosystems.
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Affiliation(s)
- Elizabeth A McDaniel
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, Canada
| | - Matthew Scarborough
- Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT, USA
| | - Daniel Girma Mulat
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada
| | - Xuan Lin
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada
| | - Pranav S Sampara
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada
| | - Heather M Olson
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Robert P Young
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Elizabeth K Eder
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Isaac K Attah
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Lye Meng Markillie
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - David W Hoyt
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Mary S Lipton
- Environmental and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Steven J Hallam
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, Canada
- ECOSCOPE Training Program, The University of British Columbia, Vancouver, BC, Canada
- Graduate Program in Bioinformatics, The University of British Columbia, Vancouver, BC, Canada
- Genome Science and Technology Program, The University of British Columbia, Vancouver, BC, Canada
- Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - Ryan M Ziels
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada.
- Genome Science and Technology Program, The University of British Columbia, Vancouver, BC, Canada.
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2
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Sakurai R, Fukuda Y, Tada C. Species-specific Primer and Probe Sets for Detection of Syntrophic Long-chain Fatty Acid-degrading Bacteria in Anaerobic Digestion Using Quantitative PCR. Microbes Environ 2023; 38:n/a. [PMID: 37357389 DOI: 10.1264/jsme2.me23023] [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: 06/27/2023] Open
Abstract
Lipid-rich wastes are energy-dense substrates for anaerobic digestion. However, long-chain fatty acids (LCFAs), key intermediates in lipid degradation, inhibit methanogenic activity. In this study, TaqMan-based qPCR assays targeting the 16S rRNA gene of the cardinal LCFA-degrading bacterial species Syntrophomonas palmitatica and S. zehnderi were developed and validated. A trial experiment showed the advantage of species-specific quantification versus genus-specific quantification in assessing bacterial capacity for lipidic waste degradation. These qPCR assays will serve as monitoring tools for estimating the LCFA-degrading capacity of anaerobic digester communities and developing an effective strategy to enrich LCFA-degrading bacteria.
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Affiliation(s)
- Riku Sakurai
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University
| | - Yasuhiro Fukuda
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University
| | - Chika Tada
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University
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3
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Yao G, Tang R, Luo H, Yuan S, Wang W, Xiao L, Chu X, Hu ZH. Zero-valent iron mediated alleviation of methanogenesis inhibition induced by organoarsenic roxarsone. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 819:152080. [PMID: 34856273 DOI: 10.1016/j.scitotenv.2021.152080] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/02/2021] [Accepted: 11/26/2021] [Indexed: 06/13/2023]
Abstract
Zero-valent iron (ZVI) can enhance anaerobic digestion, and has great potential to alleviate/eliminate methanogenesis inhibition. Little is known about the feasibility of utilizing ZVI to alleviate methanogenesis inhibition that is caused by typical animal feed additive roxarsone in livestock wastewater. In this study, the role of ZVI on alleviating roxarsone-induced methanogenic inhibition and its mechanisms were investigated. With the increase of roxarsone concentration from 5 to 50 mg/L, the inhibition of methanogenesis increased from 3.0% to 65.7%. This inhibition was alleviated by 80.7% and 57.2% when 1.0 and 10.0 g/L ZVI were added, respectively. Due to ZVI addition, an efficient arsenic immobilization onto ZVI (45.4-85.8%) was achieved mainly through the formation of FeAsO4 precipitate and adsorption by ZVI. Under the function of ZVI, hydrogenotrophic methanogenic activity was obviously restored. The microbial community analysis indicates that the ZVI-regulated alleviation on the methanogenesis inhibition was attributed to the enrichment of Methanobacterium and Methanosarcina. The findings from this study demonstrate that ZVI addition is an effective way for treatment of organoarsenic-contaminated wastewater.
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Affiliation(s)
- Guanbao Yao
- School of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Rui Tang
- School of Civil Engineering, Hefei University of Technology, Hefei 230009, China.
| | - Haiping Luo
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Shoujun Yuan
- School of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Wei Wang
- School of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Liwen Xiao
- Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin 2, Ireland
| | - Xiangqian Chu
- School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China
| | - Zhen-Hu Hu
- School of Civil Engineering, Hefei University of Technology, Hefei 230009, China; Anhui Provincial Engineering Laboratory for Rural Water Environment and Resources, Hefei University of Technology, Hefei 230009, China; Anhui Province Key Laboratory of Industrial Wastewater and Environmental Treatment, Hefei 230024, China
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4
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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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5
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Effect of feed-to-inoculum ratio on anaerobic digestibility of high-fat content animal rendering wastewater. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2021.108215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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6
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Xie A, Deaver JA, Miller E, Popat SC. Evaluation of electrical current production in microbial electrolysis cells fed with animal rendering wastewater. CHEMOSPHERE 2021; 285:131547. [PMID: 34329127 DOI: 10.1016/j.chemosphere.2021.131547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/07/2021] [Accepted: 07/10/2021] [Indexed: 06/13/2023]
Abstract
Anode-respiring bacteria (ARB) generate electrical current from the oxidation of short chain fatty acids (SCFA), primarily acetate, in microbial electrolysis cells (MECs). Animal rendering wastewater (RW) has high fat content, which under anaerobic conditions can yield acetate, making RW a potential feed for MECs. Yet, excess intermediate long chain fatty acids (LCFA) may limit conversion of LCFA and SCFA, and impact ARB activity. Here, we evaluated electrical current production in single-chamber MECs fed with RW. In RW-fed MECs, 34.26 ± 2.69% of the COD provided was converted to electrical current in an 80-day batch cycle. LCFA accumulated in RW-fed MECs, during which conversion of acetate to electrical current was limited. Diverse sulfate-reducing microorganisms were present in the anode biofilm in RW-fed MECs, whereas the genus Geobacter dominated in inoculum-only control MECs. Detection of H2-utilizing homoacetogens suggested some internal cycling of H2 produced at the cathode. Overall, this study shows that current production is possible from RW, but to be a viable process for RW treatment, further improvement in rates of COD conversion and current production is necessary along with identifying configurations and/or conditions in which the inhibitory effect of LCFA is reduced.
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Affiliation(s)
- Ao Xie
- Department of Environmental Engineering and Earth Sciences, Clemson University, 342 Computer Ct, Anderson, SC, 29625, USA
| | - Jessica A Deaver
- Department of Environmental Engineering and Earth Sciences, Clemson University, 342 Computer Ct, Anderson, SC, 29625, USA
| | - Emily Miller
- Department of Chemical and Biomolecular Engineering, Clemson University, 127 Earle Hall, Clemson, SC, 29634, USA
| | - Sudeep C Popat
- Department of Environmental Engineering and Earth Sciences, Clemson University, 342 Computer Ct, Anderson, SC, 29625, USA.
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7
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Sakurai R, Takizawa S, Fukuda Y, Tada C. Exploration of microbial communities contributing to effective methane production from scum under anaerobic digestion. PLoS One 2021; 16:e0257651. [PMID: 34591868 PMCID: PMC8483398 DOI: 10.1371/journal.pone.0257651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 09/08/2021] [Indexed: 11/18/2022] Open
Abstract
Scum is formed by the adsorption of long-chain fatty acids (LCFAs) onto biomass surface in anaerobic digestion of oily substrates. Since scum is a recalcitrant substrate to be digested, it is disposed via landfilling or incineration, which results in biomass washout and a decrease in methane yield. The microbes contributing to scum degradation are unclear. This study aimed to investigate the cardinal microorganisms in anaerobic scum digestion. We pre-incubated a sludge with scum to enrich scum-degrading microbes. Using this sludge, a 1.3-times higher methane conversion rate (73%) and a faster LCFA degradation compared with control sludge were attained. Then, we analyzed the cardinal scum-degrading microbes in this pre-incubated sludge by changing the initial scum-loading rates. Increased 16S rRNA copy numbers for the syntrophic fatty-acid degrader Syntrophomonas and hydrogenotrophic methanogens were observed in scum high-loaded samples. 16S rRNA amplicon sequencing indicated that Syntrophomonas was the most abundant genus in all the samples. The amino-acid degrader Aminobacterium and hydrolytic genera such as Defluviitoga and Sporanaerobacter became more dominant as the scum-loading rate increased. Moreover, phylogenic analysis on Syntrophomonas revealed that Syntrophomonas palmitatica, which is capable of degrading LCFAs, related species became more dominant as the scum-loading rate increased. These results indicate that a variety of microorganisms that degrade LCFAs, proteins, and sugars are involved in effective scum degradation.
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Affiliation(s)
- Riku Sakurai
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi, Japan
| | - Shuhei Takizawa
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi, Japan
- Research Fellow of Japan Society for the Promotion of Science, Japan Society for the Promotion of Science, Chiyoda-ku, Tokyo, Japan
| | - Yasuhiro Fukuda
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi, Japan
| | - Chika Tada
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi, Japan
- * E-mail:
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8
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Wang T, Zhu G, Kuang B, Jia J, Liu C, Cai G, Li C. Novel insights into the anaerobic digestion of propionate via Syntrophobacter fumaroxidans and Geobacter sulfurreducens: Process and mechanism. WATER RESEARCH 2021; 200:117270. [PMID: 34077836 DOI: 10.1016/j.watres.2021.117270] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 04/21/2021] [Accepted: 05/14/2021] [Indexed: 06/12/2023]
Abstract
The accumulation of volatile fatty acids, particularly propionic acid, significantly inhibits the efficiency of the anaerobic digestion system. In propionate degradation metabolism, the unfavorable thermodynamics of syntrophic reactions, strict ecological niche of syntrophic priopionate oxidizing bacteria, and slow metabolic rate of methanogens are regarded as major limitations. In this study, Geobacter sulfurreducens was co-cultured with Syntrophobacter fumaroxidans in bioelelectrochemical cells to analyze the propionate degradation process, impact factor, mechanism metabolic pathways, and electron transfer comprehensively. The results revealed that the syntroph S. fumaroxidans and syntrophic partner G. sulfurreducens achieved more efficient propionate degradation than the control group, comprising S. fumaroxidans and methanogens. Moreover, the carbon resource concentration and pH were both significantly correlated with propionate degradation (P < 0.01). The results further confirmed that G. sulfurreducen strengthened the consumption of H2 and acetate via direct interspecific electron transfer in propionate degradation. These findings indicate that G. sulfurreducens plays an unidentified functional role in propionate degradation.
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Affiliation(s)
- Tao Wang
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, PR China
| | - Gefu Zhu
- School of Environment and Nature Resources, Renmin University of China, Beijing 100872, PR China
| | - Bin Kuang
- School of Economics and Management, Jiangmen Polytechnic, Jiangmen 529020, PR China
| | - Jianbo Jia
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, PR China
| | - Changyu Liu
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, PR China
| | - Guanjing Cai
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China
| | - Chunxing Li
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
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9
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Iskander SM, Amha YM, Wang P, Dong Q, Liu J, Corbett M, Smith AL. Investigation of Fats, Oils, and Grease Co-digestion With Food Waste in Anaerobic Membrane Bioreactors and the Associated Microbial Community Using MinION Sequencing. Front Bioeng Biotechnol 2021; 9:613626. [PMID: 33912543 PMCID: PMC8072289 DOI: 10.3389/fbioe.2021.613626] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 02/26/2021] [Indexed: 01/23/2023] Open
Abstract
Co-digestion of fats, oils, and grease (FOG) with food waste (FW) can improve the energy recovery in anaerobic membrane bioreactors (AnMBRs). Here, we investigated the effect of co-digestion of FW and FOG in AnMBRs at fat mass loading of 0.5, 0.75, and 1.0 kg m–3 day–1 with a constant organic loading rate of 5.0 gCOD L–1 day–1 in both a single-phase (SP) and two-phase (TP) configuration. A separate mono-digestion of FW at an identical organic loading rate was used as the benchmark. During co-digestion, higher daily biogas production, ranging from 4.0 to 12.0%, was observed in the two-phase methane phase (TP-MP) reactor compared to the SP reactor, but the difference was statistically insignificant (p > 0.05) due to the high variability in daily biogas production. However, the co-digestion of FW with FOG at 1.0 kg m–3 day–1 fat loading rate significantly (p < 0.05) improved daily biogas production in both the SP (11.0%) and TP (13.0%) reactors compared to the mono-digestion of FW. Microbial community analyses using cDNA-based MinION sequencing of weekly biomass samples from the AnMBRs revealed the prevalence of Lactobacillus (92.2–95.7% relative activity) and Anaerolineaceae (13.3–57.5% relative activity), which are known as fermenters and fatty acid degraders. Syntrophic fatty acid oxidizers were mostly present in the SP and TP-MP reactors, possibly because of the low pH and short solid retention time (SRT) in the acid phase digesters. A greater abundance of the mcrA gene copies (and methanogens) was observed in the SP and MP reactors compared to the acid-phase (AP) reactors. This study demonstrates that FW and FOG can be effectively co-digested in AnMBRs and is expected to inform full-scale decisions on the optimum fat loading rate.
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Affiliation(s)
- Syeed Md Iskander
- Astani Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, CA, United States.,Department of Civil and Environmental Engineering, North Dakota State University, Fargo, ND, United States
| | - Yamrot M Amha
- Trussell Technologies, Inc., Pasadena, CA, United States
| | - Phillip Wang
- Astani Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, CA, United States
| | - Qin Dong
- Astani Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, CA, United States
| | - Juhe Liu
- Astani Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, CA, United States
| | | | - Adam L Smith
- Astani Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, CA, United States
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10
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Shakeri Yekta S, Liu T, Mendes Anacleto T, Axelsson Bjerg M, Šafarič L, Goux X, Karlsson A, Björn A, Schnürer A. Effluent solids recirculation to municipal sludge digesters enhances long-chain fatty acids degradation capacity. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:56. [PMID: 33663594 PMCID: PMC7934545 DOI: 10.1186/s13068-021-01913-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/21/2021] [Indexed: 06/05/2023]
Abstract
BACKGROUND Slow degradation kinetics of long-chain fatty acids (LCFA) and their accumulation in anaerobic digesters disrupt methanogenic activity and biogas production at high loads of waste lipids. In this study, we evaluated the effect of effluent solids recirculation on microbial LCFA (oleate) degradation capacity in continuous stirred-tank sludge digesters, with the overall aim of providing operating conditions for efficient co-digestion of waste lipids. Furthermore, the impacts of LCFA feeding frequency and sulfide on process performance and microbial community dynamics were investigated, as parameters that were previously shown to be influential on LCFA conversion to biogas. RESULTS Effluent solids recirculation to municipal sludge digesters enabled biogas production of up to 78% of the theoretical potential from 1.0 g oleate l-1 day-1. In digesters without effluent recirculation, comparable conversion efficiency could only be reached at oleate loading rates up to 0.5 g l-1 day-1. Pulse feeding of oleate (supplementation of 2.0 g oleate l-1 every second day instead of 1.0 g oleate l-1 every day) did not have a substantial impact on the degree of oleate conversion to biogas in the digesters that operated with effluent recirculation, while it marginally enhanced oleate conversion to biogas in the digesters without effluent recirculation. Next-generation sequencing of 16S rRNA gene amplicons of bacteria and archaea revealed that pulse feeding resulted in prevalence of fatty acid-degrading Smithella when effluent recirculation was applied, whereas Candidatus Cloacimonas prevailed after pulse feeding of oleate in the digesters without effluent recirculation. Combined oleate pulse feeding and elevated sulfide level contributed to increased relative abundance of LCFA-degrading Syntrophomonas and enhanced conversion efficiency of oleate, but only in the digesters without effluent recirculation. CONCLUSIONS Effluent solids recirculation improves microbial LCFA degradation capacity, providing possibilities for co-digestion of larger amounts of waste lipids with municipal sludge.
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Affiliation(s)
- Sepehr Shakeri Yekta
- Department of Thematic Studies-Environmental Change, Linköping University, 58183, Linköping, Sweden.
- Biogas Research Center, Linköping University, 58183, Linköping, Sweden.
| | - Tong Liu
- Biogas Research Center, Linköping University, 58183, Linköping, Sweden
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala BioCenter, 75007, Uppsala, Sweden
| | - Thuane Mendes Anacleto
- Post Graduate Program in Plant Biotechnology and Bioprocesses, Federal University of Rio de Janeiro, Rio de Janeiro, 21941-901, Brazil
| | - Mette Axelsson Bjerg
- Department of Thematic Studies-Environmental Change, Linköping University, 58183, Linköping, Sweden
- Biogas Research Center, Linköping University, 58183, Linköping, Sweden
| | - Luka Šafarič
- Department of Thematic Studies-Environmental Change, Linköping University, 58183, Linköping, Sweden
- Biogas Research Center, Linköping University, 58183, Linköping, Sweden
| | - Xavier Goux
- Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology, 4422, Belvaux, Luxembourg
| | - Anna Karlsson
- Biogas Research Center, Linköping University, 58183, Linköping, Sweden
- Scandinavian Biogas Fuels AB, 11160, Stockholm, Sweden
| | - Annika Björn
- Department of Thematic Studies-Environmental Change, Linköping University, 58183, Linköping, Sweden
- Biogas Research Center, Linköping University, 58183, Linköping, Sweden
| | - Anna Schnürer
- Biogas Research Center, Linköping University, 58183, Linköping, Sweden
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala BioCenter, 75007, Uppsala, Sweden
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11
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Performance of Anaerobic Digestion of Acidified Palm Oil Mill Effluent under Various Organic Loading Rates and Temperatures. WATER 2020. [DOI: 10.3390/w12092432] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
This study compared the performance of thermophilic and mesophilic digesters of an anaerobic digestion system from palm oil mill effluent (POME), in which temperature is a key parameter that can greatly affect the performance of anaerobic digestion. The digesters were incubated at two distinct temperatures of 55 and 37 °C, and operated with varying organic loading rates (OLRs) of 2.4, 3.2, and 4.0 g COD/L.d by altering the chemical oxygen demand (COD) of acidified POME during feeding. The results indicated that the performance of anaerobic digestion increased as the OLR increased from 2.4 to 4.0 g COD/L.d. At the OLR of 4.0 g COD/L.d, the thermophilic condition showed the highest methane yield of 0.31 ± 0.01 L/g COD, accompanied by the highest COD removal and volatile solid reduction, which were found to be higher than the mesophilic condition. Microbial community analysis via denaturing gradient gel electrophoresis (DGGE) revealed that Methanothermobacter sp. emerges as the dominant microbe, which is known to utilize the carbon dioxide pathway with hydrogen acting as an electron donor for methane formation
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Ziels RM, Nobu MK, Sousa DZ. Elucidating Syntrophic Butyrate-Degrading Populations in Anaerobic Digesters Using Stable-Isotope-Informed Genome-Resolved Metagenomics. mSystems 2019; 4:e00159-19. [PMID: 31387934 PMCID: PMC6687939 DOI: 10.1128/msystems.00159-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 07/12/2019] [Indexed: 11/20/2022] Open
Abstract
Linking the genomic content of uncultivated microbes to their metabolic functions remains a critical challenge in microbial ecology. Resolving this challenge has implications for improving our management of key microbial interactions in biotechnologies such as anaerobic digestion, which relies on slow-growing syntrophic and methanogenic communities to produce renewable methane from organic waste. In this study, we combined DNA stable-isotope probing (SIP) with genome-centric metagenomics to recover the genomes of populations enriched in 13C after growing on [13C]butyrate. Differential abundance analysis of recovered genomic bins across the SIP metagenomes identified two metagenome-assembled genomes (MAGs) that were significantly enriched in heavy [13C]DNA. Phylogenomic analysis assigned one MAG to the genus Syntrophomonas and the other MAG to the genus Methanothrix. Metabolic reconstruction of the annotated genomes showed that the Syntrophomonas genome encoded all the enzymes for beta-oxidizing butyrate, as well as several mechanisms for interspecies electron transfer via electron transfer flavoproteins, hydrogenases, and formate dehydrogenases. The Syntrophomonas genome shared low average nucleotide identity (<95%) with any cultured representative species, indicating that it is a novel species that plays a significant role in syntrophic butyrate degradation within anaerobic digesters. The Methanothrix genome contained the complete pathway for acetoclastic methanogenesis, indicating that it was enriched in 13C from syntrophic acetate transfer. This study demonstrates the potential of stable-isotope-informed genome-resolved metagenomics to identify in situ interspecies metabolic cooperation within syntrophic consortia important to anaerobic waste treatment as well as global carbon cycling.IMPORTANCE Predicting the metabolic potential and ecophysiology of mixed microbial communities remains a major challenge, especially for slow-growing anaerobes that are difficult to isolate. Unraveling the in situ metabolic activities of uncultured species may enable a more descriptive framework to model substrate transformations by microbiomes, which has broad implications for advancing the fields of biotechnology, global biogeochemistry, and human health. Here, we investigated the in situ function of mixed microbiomes by combining stable-isotope probing with metagenomics to identify the genomes of active syntrophic populations converting butyrate, a C4 fatty acid, into methane within anaerobic digesters. This approach thus moves beyond the mere presence of metabolic genes to resolve "who is doing what" by obtaining confirmatory assimilation of the labeled substrate into the DNA signature. Our findings provide a framework to further link the genomic identities of uncultured microbes with their ecological function within microbiomes driving many important biotechnological and global processes.
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Affiliation(s)
- Ryan M Ziels
- Department of Civil Engineering, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington, USA
| | - Masaru K Nobu
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
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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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Shakeri Yekta S, Liu T, Axelsson Bjerg M, Šafarič L, Karlsson A, Björn A, Schnürer A. Sulfide level in municipal sludge digesters affects microbial community response to long-chain fatty acid loads. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:259. [PMID: 31700542 PMCID: PMC6825336 DOI: 10.1186/s13068-019-1598-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 10/22/2019] [Indexed: 05/19/2023]
Abstract
BACKGROUND Waste lipids are attractive substrates for co-digestion with primary and activated sewage sludge (PASS) to improve biogas production at wastewater treatment plants. However, slow conversion rates of long-chain fatty acids (LCFA), produced during anaerobic digestion (AD), limit the applicability of waste lipids as co-substrates for PASS. Previous observations indicate that the sulfide level in PASS digesters affects the capacity of microbial communities to convert LCFA to biogas. This study assessed the microbial community response to LCFA loads in relation to sulfide level during AD of PASS by investigating process performance and microbial community dynamics upon addition of oleate (C18:1) and stearate (C18:0) to PASS digesters at ambient and elevated sulfide levels. RESULTS Conversion of LCFA to biogas was limited (30% of theoretical biogas potential) during continuous co-digestion with PASS, which resulted in further LCFA accumulation. However, the accumulated LCFA were converted to biogas (up to 66% of theoretical biogas potential) during subsequent batch-mode digestion, performed without additional substrate load. Elevated sulfide level stimulated oleate (but not stearate) conversion to acetate, but oleate and sulfide imposed a synergistic limiting effect on acetoclastic methanogenesis and biogas formation. Next-generation sequencing of 16S rRNA gene amplicons of bacteria and archaea showed that differences in sulfide level and LCFA type resulted in microbial community alterations with distinctly different patterns. Taxonomic profiling of the sequencing data revealed that the phylum Cloacimonetes is likely a key group during LCFA degradation in PASS digesters, where different members take part in degradation of saturated and unsaturated LCFA; genus W5 (family Cloacimonadaceae) and family W27 (order Cloacimonadales), respectively. In addition, LCFA-degrading Syntrophomonas, which is commonly present in lipid-fed digesters, increased in relative abundance after addition of oleate at elevated sulfide level, but not without sulfide or after stearate addition. Stearate conversion to biogas was instead associated with increasing abundance of hydrogen-producing Smithella and hydrogenotrophic Methanobacterium. CONCLUSIONS Long-chain fatty acid chain saturation and sulfide level are selective drivers for establishment of LCFA-degrading microbial communities in municipal sludge digesters.
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Affiliation(s)
- Sepehr Shakeri Yekta
- Department of Thematic Studies-Environmental Change and Biogas Research Center, Linköping University, 581 83 Linköping, Sweden
| | - Tong Liu
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
| | - Mette Axelsson Bjerg
- Department of Thematic Studies-Environmental Change and Biogas Research Center, Linköping University, 581 83 Linköping, Sweden
| | - Luka Šafarič
- Department of Thematic Studies-Environmental Change and Biogas Research Center, Linköping University, 581 83 Linköping, Sweden
| | | | - Annika Björn
- Department of Thematic Studies-Environmental Change and Biogas Research Center, Linköping University, 581 83 Linköping, Sweden
| | - Anna Schnürer
- Department of Thematic Studies-Environmental Change and Biogas Research Center, Linköping University, 581 83 Linköping, Sweden
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
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Substrate-Induced Response in Biogas Process Performance and Microbial Community Relates Back to Inoculum Source. Microorganisms 2018; 6:microorganisms6030080. [PMID: 30081593 PMCID: PMC6163493 DOI: 10.3390/microorganisms6030080] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/01/2018] [Accepted: 08/02/2018] [Indexed: 12/31/2022] Open
Abstract
This study investigated whether biogas reactor performance, including microbial community development, in response to a change in substrate composition is influenced by initial inoculum source. For the study, reactors previously operated with the same grass–manure mixture for more than 120 days and started with two different inocula were used. These reactors initially showed great differences depending on inoculum source, but eventually showed similar performance and overall microbial community structure. At the start of the present experiment, the substrate was complemented with milled feed wheat, added all at once or divided into two portions. The starting hypothesis was that process performance depends on initial inoculum source and microbial diversity, and thus that reactor performance is influenced by the feeding regime. In response to the substrate change, all reactors showed increases and decreases in volumetric and specific methane production, respectively. However, specific methane yield and development of the microbial community showed differences related to the initial inoculum source, confirming the hypothesis. However, the different feeding regimes had only minor effects on process performance and overall community structure, but still induced differences in the cellulose-degrading community and in cellulose degradation.
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Ziels RM, Svensson BH, Sundberg C, Larsson M, Karlsson A, Yekta SS. Microbial rRNA gene expression and co-occurrence profiles associate with biokinetics and elemental composition in full-scale anaerobic digesters. Microb Biotechnol 2018; 11:694-709. [PMID: 29633555 PMCID: PMC6011980 DOI: 10.1111/1751-7915.13264] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 03/05/2018] [Accepted: 03/07/2018] [Indexed: 11/29/2022] Open
Abstract
This study examined whether the abundance and expression of microbial 16S rRNA genes were associated with elemental concentrations and substrate conversion biokinetics in 20 full-scale anaerobic digesters, including seven municipal sewage sludge (SS) digesters and 13 industrial codigesters. SS digester contents had higher methane production rates from acetate, propionate and phenyl acetate compared to industrial codigesters. SS digesters and industrial codigesters were distinctly clustered based on their elemental concentrations, with higher concentrations of NH3 -N, Cl, K and Na observed in codigesters. Amplicon sequencing of 16S rRNA genes and reverse-transcribed 16S rRNA revealed divergent grouping of microbial communities between mesophilic SS digesters, mesophilic codigesters and thermophilic digesters. Higher intradigester distances between Archaea 16S rRNA and rRNA gene profiles were observed in mesophilic codigesters, which also had the lowest acetate utilization biokinetics. Constrained ordination showed that microbial rRNA and rRNA gene profiles were significantly associated with maximum methane production rates from acetate, propionate, oleate and phenyl acetate, as well as concentrations of NH3 -N, Fe, S, Mo and Ni. A co-occurrence network of rRNA gene expression confirmed the three main clusters of anaerobic digester communities based on active populations. Syntrophic and methanogenic taxa were highly represented within the subnetworks, indicating that obligate energy-sharing partnerships play critical roles in stabilizing the digester microbiome. Overall, these results provide new evidence showing that different feed substrates associate with different micronutrient compositions in anaerobic digesters, which in turn may influence microbial abundance, activity and function.
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Affiliation(s)
- Ryan M Ziels
- Department of Civil Engineering, The University of British Columbia, Vancouver, BC, Canada
| | - Bo H Svensson
- Department of Thematic Studies-Environmental Change, Linköping University, Linköping, Sweden.,Biogas Research Center, Linköping University, Linköping, Sweden
| | - Carina Sundberg
- Department of Thematic Studies-Environmental Change, Linköping University, Linköping, Sweden
| | - Madeleine Larsson
- Department of Thematic Studies-Environmental Change, Linköping University, Linköping, Sweden.,Biogas Research Center, Linköping University, Linköping, Sweden
| | | | - Sepehr Shakeri Yekta
- Department of Thematic Studies-Environmental Change, Linköping University, Linköping, Sweden.,Biogas Research Center, Linköping University, Linköping, Sweden
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Ziels RM, Sousa DZ, Stensel HD, Beck DAC. DNA-SIP based genome-centric metagenomics identifies key long-chain fatty acid-degrading populations in anaerobic digesters with different feeding frequencies. THE ISME JOURNAL 2018; 12:112-123. [PMID: 28895946 PMCID: PMC5737908 DOI: 10.1038/ismej.2017.143] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 06/22/2017] [Accepted: 07/22/2017] [Indexed: 12/14/2022]
Abstract
Fats, oils and greases (FOG) are energy-dense wastes that can be added to anaerobic digesters to substantially increase biomethane recovery via their conversion through long-chain fatty acids (LCFAs). However, a better understanding of the ecophysiology of syntrophic LCFA-degrading microbial communities in anaerobic digesters is needed to develop operating strategies that mitigate inhibitory LCFA accumulation from FOG. In this research, DNA stable isotope probing (SIP) was coupled with metagenomic sequencing for a genome-centric comparison of oleate (C18:1)-degrading populations in two anaerobic codigesters operated with either a pulse feeding or continuous-feeding strategy. The pulse-fed codigester microcosms converted oleate into methane at over 20% higher rates than the continuous-fed codigester microcosms. Differential coverage binning was demonstrated for the first time to recover population genome bins (GBs) from DNA-SIP metagenomes. About 70% of the 13C-enriched GBs were taxonomically assigned to the Syntrophomonas genus, thus substantiating the importance of Syntrophomonas species to LCFA degradation in anaerobic digesters. Phylogenetic comparisons of 13C-enriched GBs showed that phylogenetically distinct Syntrophomonas GBs were unique to each codigester. Overall, these results suggest that syntrophic populations in anaerobic digesters can have different adaptive capacities, and that selection for divergent populations may be achieved by adjusting reactor operating conditions to maximize biomethane recovery.
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Affiliation(s)
- Ryan M Ziels
- Department of Civil Engineering, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | - H David Stensel
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
| | - David A C Beck
- eScience Institute, University of Washington, Seattle, WA, USA
- Department of Chemical Engineering, University of Washington, Seattle, WA, USA
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Xu R, Yang ZH, Zheng Y, Zhang HB, Liu JB, Xiong WP, Zhang YR, Ahmad K. Depth-resolved microbial community analyses in the anaerobic co-digester of dewatered sewage sludge with food waste. BIORESOURCE TECHNOLOGY 2017; 244:824-835. [PMID: 28841787 DOI: 10.1016/j.biortech.2017.07.056] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 07/08/2017] [Accepted: 07/10/2017] [Indexed: 06/07/2023]
Abstract
This study evaluated the impacts of FW addition on co-digestion in terms of microbial community. Anaerobic co-digestion (AcoD) reactors were conducted at gradually increased addition of food waste (FW) from 0 to 4kg-VSm-3d-1 for 220days. Although no markable acidification was found at an OLR of 4kg-VSm-3d-1, the unhealthy operation was observed in aspect of an inhibited methane yield (185mLg-1VSadded), which was restricted by 40% when compared with its peak value. Deterioration of digestion process was timely indicated by the dramatic decrease of archaeal population and microbial biodiversity. Furthermore, the cooperation network showed a considerable number of rare species (<1%) were strongly correlated with methane production, which were frequently overlooked due to the limits of detecting resolution or analysis methods before. Advances in the analysis of sensitive microbial community enable us to detect the early disturbances in AcoD reactors.
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Affiliation(s)
- Rui Xu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Zhao-Hui Yang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
| | - Yue Zheng
- Department of Chemical Engineering, University of Washington, Seattle, WA 98195, United States
| | - Hai-Bo Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Jian-Bo Liu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Wei-Ping Xiong
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Yan-Ru Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Kito Ahmad
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
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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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Ziels RM, Beck DAC, Stensel HD. Long-chain fatty acid feeding frequency in anaerobic codigestion impacts syntrophic community structure and biokinetics. WATER RESEARCH 2017; 117:218-229. [PMID: 28402870 DOI: 10.1016/j.watres.2017.03.060] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 05/23/2023]
Abstract
This study investigated the impacts of long-chain fatty acid (LCFA) feeding frequencies on microbial community structure, bioconversion kinetics, and process stability during anaerobic codigestion. Parallel laboratory-scale anaerobic codigesters fed with dairy cattle manure were either pulse-fed every two days or continuously-fed daily, respectively, with oleate (C18:1) in incremental step increases over 200 days up to 64% of the influent chemical oxygen demand (COD). The effluent acetate concentration exceeded 3000 mg/L in the continuous-fed codigester at the highest oleate loading rate, but remained below 100 mg/L in the pulse-fed codigester at the end of its 48-hr oleate feed cycle. Maximum substrate conversion rates of oleate (qmax, oleate) and acetate (qmax, acetate) were significantly higher in the pulse-fed codigester compared to the continuous-fed codigester. 16S rRNA gene amplicon sequencing showed that Bacteria and Archaea community profiles diverged based on the codigester LCFA feeding pattern and loading rate. LCFA-degrading Syntrophomonas bacteria were significantly enriched in both LCFA codigesters relative to the control digester. The pulse-fed codigester had the highest community fraction of Syntrophomonas 16S rRNA genes by the end of the experiment with 43% of Bacteria amplicon sequences. qmax, oleate and qmax, acetate values were both significantly correlated to absolute concentrations of Syntrophomonas and Methanosaeta 16S rRNA genes, respectively. Multiple-linear regression models based on the absolute abundance of Syntrophomonas and Methanosaeta taxa provided improved predictions of oleate and acetate bioconversion kinetics, respectively. These results collectively suggest that pulse feeding rather than continuous feeding LCFA during anaerobic codigestion selected for higher microbial bioconversion kinetics and functional stability, which were related to changes in the physiological diversity and adaptive capacity of syntrophic and methanogenic communities.
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Affiliation(s)
- Ryan M Ziels
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA; Department of Civil Engineering, University of British Columbia, Vancouver, Canada.
| | - David A C Beck
- eScience Institute, University of Washington, Seattle, WA, USA; Department of Chemical Engineering, University of Washington, Seattle, WA, USA
| | - H David Stensel
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
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21
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Importance of sulfide interaction with iron as regulator of the microbial community in biogas reactors and its effect on methanogenesis, volatile fatty acids turnover, and syntrophic long-chain fatty acids degradation. J Biosci Bioeng 2017; 123:597-605. [PMID: 28057469 DOI: 10.1016/j.jbiosc.2016.12.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 10/18/2016] [Accepted: 12/06/2016] [Indexed: 12/30/2022]
Abstract
The inhibitory effects of sulfide on microbial processes during anaerobic digestion have been widely addressed. However, other effects of sulfide are less explored, given that sulfide is a potential sulfur source for microorganisms and its high reactivity triggers a suit of abiotic reactions. We demonstrated that sulfide interaction with Fe regulates the dynamics and activities of microbial community during anaerobic digestion. This was manifested by the S:Fe molar ratio, whose increase adversely influenced the acetoclastic methanogens, Methanosaeta, and turnover of acetate. Dynamics of hydrogenotrophic methanogens, Methanoculleus and Methanobrevibacter, were presumably influenced by sulfide-induced changes in the partial pressure of hydrogen. Interestingly, conversion of the long-chain fatty acid (LCFA), oleate, to methane was enhanced together with the abundance of LCFA-degrading, β-oxidizing Syntrophomonas at an elevated S:Fe molar ratio. The results suggested that sulfur chemical speciation is a controlling factor for microbial community functions in anaerobic digestion processes.
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22
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Meng Y, Luan F, Yuan H, Chen X, Li X. Enhancing anaerobic digestion performance of crude lipid in food waste by enzymatic pretreatment. BIORESOURCE TECHNOLOGY 2017; 224:48-55. [PMID: 27839678 DOI: 10.1016/j.biortech.2016.10.052] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 10/09/2016] [Accepted: 10/19/2016] [Indexed: 06/06/2023]
Abstract
Three lipases were applied to hydrolyze the floatable grease (FG) in the food waste for eliminating FG inhibition and enhancing digestion performance in anaerobic process. Lipase-I, Lipase-II, and Lipase-III obtained from different sources were used. Animal fat (AF) and vegetable oil (VO) are major crude lipids in Chinese food waste, therefore, applied as substrates for anaerobic digestion tests. The results showed that Lipase-I and Lipase-II were capable of obviously releasing long chain fatty acid in AF, VO, and FG when hydrolyzed in the conditions of 24h, 1000-1500μL and 40-50°C. Compared to the untreated controls, the biomethane production rate were increased by 80.8-157.7%, 26.9-53.8%, and 37.0-40.7% for AF, VO, and FG, respectively, and the digestion time was shortened by 10-40d. The finding suggests that pretreating lipids with appropriate lipase could be one of effective methods for enhancing anaerobic digestion of food waste rich in crude lipid.
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Affiliation(s)
- Ying Meng
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing 100029, China; State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Fubo Luan
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Hairong Yuan
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing 100029, China
| | - Xue Chen
- China Power Conservation & Environment Protection CO., LTD, Beijing 100020, China
| | - Xiujin Li
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing 100029, China.
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Ziels RM, Karlsson A, Beck DAC, Ejlertsson J, Yekta SS, Bjorn A, Stensel HD, Svensson BH. Microbial community adaptation influences long-chain fatty acid conversion during anaerobic codigestion of fats, oils, and grease with municipal sludge. WATER RESEARCH 2016; 103:372-382. [PMID: 27486949 DOI: 10.1016/j.watres.2016.07.043] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 06/30/2016] [Accepted: 07/19/2016] [Indexed: 05/23/2023]
Abstract
Codigesting fats, oils, and greases with municipal wastewater sludge can greatly improve biomethane recovery at wastewater treatment facilities. Process loading rates of fats, oils, and greases have been previously tested with little knowledge of the digester microbial community structure, and high transient fat loadings have led to long chain fatty acid (LCFA) accumulation and digester upsets. This study utilized recently-developed quantitative PCR assays for syntrophic LCFA-degrading bacteria along with 16S amplicon sequencing to relate changes in microbial community structure to LCFA accumulation during transient loading increases to an anaerobic codigester receiving waste restaurant oil and municipal wastewater sludge. The 16S rRNA gene concentration of the syntrophic β-oxidizing genus Syntrophomonas increased to ∼15% of the Bacteria community in the codigester, but stayed below 3% in the control digester that was fed only wastewater sludge. Methanosaeta and Methanospirillum were the dominant methanogenic genera enriched in the codigester, and together comprised over 80% of the Archaea community by the end of the experimental period. Constrained ordination showed that changes in the codigester Bacteria and Archaea community structures were related to measures of digester performance. Notably, the effluent LCFA concentration in the codigester was positively correlated to the specific loading rate of waste oil normalized to the Syntrophomonas 16S rRNA concentration. Specific loading rates of 0-1.5 × 10(-12) g VS oil/16S gene copies-day resulted in LCFA concentrations below 30 mg/g TS, whereas LCFA accumulated up to 104 mg/g TS at higher transient loading rates. Based on the community-dependent loading limitations found, enhanced biomethane production from high loadings of fats, oils and greases can be achieved by promoting a higher biomass of slow-growing syntrophic consortia, such as with longer digester solids retention times. This work also demonstrates the potential for controlling the loading rate of fats, oils, and greases based on the analysis of the codigester community structure, such as with quantitative PCR measurements of syntrophic LCFA-degrading bacteria abundance.
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Affiliation(s)
- Ryan M Ziels
- Civil and Environmental Engineering, University of Washington, WA, USA.
| | | | | | | | - Sepehr Shakeri Yekta
- Department of Thematic Studies - Environmental Change, Linköping University, Sweden
| | - Annika Bjorn
- Department of Thematic Studies - Environmental Change, Linköping University, Sweden
| | - H David Stensel
- Civil and Environmental Engineering, University of Washington, WA, USA
| | - Bo H Svensson
- Department of Thematic Studies - Environmental Change, Linköping University, Sweden.
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Kougias PG, Treu L, Campanaro S, Zhu X, Angelidaki I. Dynamic functional characterization and phylogenetic changes due to Long Chain Fatty Acids pulses in biogas reactors. Sci Rep 2016; 6:28810. [PMID: 27353502 PMCID: PMC4926282 DOI: 10.1038/srep28810] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/08/2016] [Indexed: 01/26/2023] Open
Abstract
The process stability of biogas plants is often deteriorated by the accumulation of Long Chain Fatty Acids (LCFA). The microbial community shifts due to LCFA disturbances have been poorly understood as the molecular techniques used were not able to identify the genome characteristics of uncultured microorganisms, and additionally, the presence of limited number of reference genomes in public databases prevented the comprehension of specific functional roles characterizing these microorganisms. The present study is the first research which deciphers by means of high throughput shotgun sequencing the dynamics of the microbial community during an inhibitory shock load induced by single pulses of unsaturated LCFA at two different concentrations (i.e. 2 g/L-reactor and 3 g/L-reactor). The metagenomic analysis showed that only the microbes associated with LCFA degradation could encode proteins related to "chemotaxis" and "flagellar assembly", which promoted the ability to move towards the LCFA sources so as to degrade them. Moreover, the syntrophic interactions found between Syntrophomonas sp. together with Methanosarcina sp. were possibly assigned to the menaquinone-electron transfer. Finally, it was proven that a previously exposed to LCFA inoculum is more efficient in the degradation process of LCFA due to the specialization of the microbial consortium.
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Affiliation(s)
- Panagiotis G. Kougias
- Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Laura Treu
- Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Stefano Campanaro
- Department of Biology, University of Padova, Via U. Bassi 58/b, 35121, Padova Italy
| | - Xinyu Zhu
- Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Irini Angelidaki
- Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark
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Schnürer A. Biogas Production: Microbiology and Technology. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016; 156:195-234. [PMID: 27432246 DOI: 10.1007/10_2016_5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Biogas, containing energy-rich methane, is produced by microbial decomposition of organic material under anaerobic conditions. Under controlled conditions, this process can be used for the production of energy and a nutrient-rich residue suitable for use as a fertilising agent. The biogas can be used for production of heat, electricity or vehicle fuel. Different substrates can be used in the process and, depending on substrate character, various reactor technologies are available. The microbiological process leading to methane production is complex and involves many different types of microorganisms, often operating in close relationships because of the limited amount of energy available for growth. The microbial community structure is shaped by the incoming material, but also by operating parameters such as process temperature. Factors leading to an imbalance in the microbial community can result in process instability or even complete process failure. To ensure stable operation, different key parameters, such as levels of degradation intermediates and gas quality, are often monitored. Despite the fact that the anaerobic digestion process has long been used for industrial production of biogas, many questions need still to be resolved to achieve optimal management and gas yields and to exploit the great energy and nutrient potential available in waste material. This chapter discusses the different aspects that need to be taken into consideration to achieve optimal degradation and gas production, with particular focus on operation management and microbiology.
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Affiliation(s)
- Anna Schnürer
- Department of Microbiology, Swedish University of Agricultural Sciences, 7025, 750 07, Uppsala, Sweden.
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