1
|
Park MJ, Kim YJ, Park M, Yu J, Namirimu T, Roh YR, Kwon KK. Establishment of Genome Based Criteria for Classification of the Family Desulfovibrionaceae and Proposal of Two Novel Genera, Alkalidesulfovibrio gen. nov. and Salidesulfovibrio gen. nov. Front Microbiol 2022; 13:738205. [PMID: 35694308 PMCID: PMC9174804 DOI: 10.3389/fmicb.2022.738205] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 04/11/2022] [Indexed: 01/14/2023] Open
Abstract
Bacteria in the Desulfovibrionaceae family, which contribute to S element turnover as sulfate-reducing bacteria (SRB) and disproportionation of partially oxidized sulfoxy anions, have been extensively investigated since the importance of the sulfur cycle emerged. Novel species belonging to this taxon are frequently reported, because they exist in various environments and are easy to culture using established methods. Due to the rapid expansion of the taxon, correction and reclassification have been conducted. The development of high-throughput sequencing facilitated rapid expansion of genome sequence database. Genome-based criteria, based on these databases, proved to be potential classification standard by overcoming the limitations of 16S rRNA-based phylogeny. Although standards methods for taxogenomics are being established, the addition of a novel genus requires extensive calculations with taxa, including many species, such as Desulfovibrionaceae. Thus, the genome-based criteria for classification of Desulfovibrionaceae were established and validated in this study. The average amino-acid identity (AAI) cut-off value, 63.43 ± 0.01, was calculated to be an appropriate criterion for genus delineation of the family Desulfovibrionaceae. By applying the AAI cut-off value, 88 genomes of the Desulfovibrionaceae were divided into 27 genera, which follows the core gene phylogeny results. In this process, two novel genera (Alkalidesulfovibrio and Salidesulfovibrio) and one former invalid genus (“Psychrodesulfovibrio”) were officially proposed. Further, by applying the 95–96% average nucleotide identity (ANI) standard and the 70% digital DNA–DNA hybridization standard values for species delineation of strains that were classified as the same species, five strains have the potential to be newly classified. After verifying that the classification was appropriately performed through relative synonymous codon usage analysis, common characteristics were listed by group. In addition, by detecting metal resistance related genes via in silico analysis, it was confirmed that most strains display metal tolerance.
Collapse
Affiliation(s)
- Mi-Jeong Park
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan, South Korea
- Department of Applied Ocean Science, University of Science and Technology, Daejeon, South Korea
| | - Yun Jae Kim
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan, South Korea
| | - Myeongkyu Park
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, South Korea
| | - Jihyun Yu
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan, South Korea
- Department of Applied Ocean Science, University of Science and Technology, Daejeon, South Korea
| | - Teddy Namirimu
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan, South Korea
- Department of Applied Ocean Science, University of Science and Technology, Daejeon, South Korea
| | - Yoo-Rim Roh
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan, South Korea
- Department of Applied Ocean Science, University of Science and Technology, Daejeon, South Korea
| | - Kae Kyoung Kwon
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan, South Korea
- Department of Applied Ocean Science, University of Science and Technology, Daejeon, South Korea
- *Correspondence: Kae Kyoung Kwon,
| |
Collapse
|
2
|
Waite DW, Chuvochina M, Pelikan C, Parks DH, Yilmaz P, Wagner M, Loy A, Naganuma T, Nakai R, Whitman WB, Hahn MW, Kuever J, Hugenholtz P. Proposal to reclassify the proteobacterial classes Deltaproteobacteria and Oligoflexia, and the phylum Thermodesulfobacteria into four phyla reflecting major functional capabilities. Int J Syst Evol Microbiol 2020; 70:5972-6016. [DOI: 10.1099/ijsem.0.004213] [Citation(s) in RCA: 696] [Impact Index Per Article: 174.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The class
Deltaproteobacteria
comprises an ecologically and metabolically diverse group of bacteria best known for dissimilatory sulphate reduction and predatory behaviour. Although this lineage is the fourth described class of the phylum
Proteobacteria
, it rarely affiliates with other proteobacterial classes and is frequently not recovered as a monophyletic unit in phylogenetic analyses. Indeed, one branch of the class
Deltaproteobacteria
encompassing Bdellovibrio-like predators was recently reclassified into a separate proteobacterial class, the
Oligoflexia
. Here we systematically explore the phylogeny of taxa currently assigned to these classes using 120 conserved single-copy marker genes as well as rRNA genes. The overwhelming majority of markers reject the inclusion of the classes
Deltaproteobacteria
and
Oligoflexia
in the phylum
Proteobacteria
. Instead, the great majority of currently recognized members of the class
Deltaproteobacteria
are better classified into four novel phylum-level lineages. We propose the names Desulfobacterota phyl. nov. and Myxococcota phyl. nov. for two of these phyla, based on the oldest validly published names in each lineage, and retain the placeholder name SAR324 for the third phylum pending formal description of type material. Members of the class
Oligoflexia
represent a separate phylum for which we propose the name Bdellovibrionota phyl. nov. based on priority in the literature and general recognition of the genus Bdellovibrio. Desulfobacterota phyl. nov. includes the taxa previously classified in the phylum
Thermodesulfobacteria
, and these reclassifications imply that the ability of sulphate reduction was vertically inherited in the
Thermodesulfobacteria
rather than laterally acquired as previously inferred. Our analysis also indicates the independent acquisition of predatory behaviour in the phyla Myxococcota and Bdellovibrionota, which is consistent with their distinct modes of action. This work represents a stable reclassification of one of the most taxonomically challenging areas of the bacterial tree and provides a robust framework for future ecological and systematic studies.
Collapse
Affiliation(s)
- David W Waite
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| | - Maria Chuvochina
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| | - Claus Pelikan
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology, Vienna, Austria
| | - Donovan H Parks
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| | | | - Michael Wagner
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology, Vienna, Austria
| | - Alexander Loy
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology, Vienna, Austria
| | | | - Ryosuke Nakai
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Hokkaido, Japan
| | - William B Whitman
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Martin W Hahn
- Research Department for Limnology, University of Innsbruck, Mondsee, Austria
| | - Jan Kuever
- Department of Microbiology, Bremen Institute for Materials Testing, Bremen, Germany
| | - Philip Hugenholtz
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
| |
Collapse
|
3
|
Han K, Yoon J, Yeum Y, Park S, Kim HK, Kim M, Chung HM, Kwon S, Yun ST, Kim Y. Efficacy of in situ well-based denitrification bio-barrier (WDB) remediating high nitrate flux in groundwater near a stock-raising complex. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 258:110004. [PMID: 31929050 DOI: 10.1016/j.jenvman.2019.110004] [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: 08/31/2019] [Revised: 12/14/2019] [Accepted: 12/15/2019] [Indexed: 06/10/2023]
Abstract
This study assessed the feasibility of an in situ well-based denitrification bio-barrier (WDB) for managing groundwater contaminated with high-strength nitrate. To evaluate the efficacy of WDB using fumarate as a carbon source and/or electron donor, three sequential single-well push-pull tests (SWPPTs) were conducted at six test sites. The values of the isotope enrichment factor (ɛ) ranging from -6.5‰ to -22.6‰ and the detection and degradation of nitrite and nitrous oxide confirmed complete in situ denitrification of nitrate to nitrogen gas. The ratio of the first-order rate coefficient of fumarate to nitrate (k1,fum/k1,NO3) was obtained to estimate the amount and frequency of fumarate injection for the effective design of WDB. At three sites, the ratios ranged from 0.67 to 0.80, while the other two sites showed higher ratios of 2.97 and 2.20 than the theoretical values and significant amounts of sulfate reduction, theoretically equivalent to 6.5% of total fumarate consumption. Considering the theoretical mole ratio of fumarate to nitrate of 0.98, the amount and frequency of fumarate injection is site specific. During the operating WDB, the average annual nitrate mass degraded (95% CI) was 2.2 ± 1.0 kg N/yr/well. The amount of N reduced by one well of WDB is equivalent to treating 110 m3 of groundwater at 30 mg N/L to the level of 10 mg N/L for one year. WDB would be an effective remediation option for managing high nitrate flux in groundwater.
Collapse
Affiliation(s)
- Kyungjin Han
- Department of Environmental Engineering, Korea University, Sejong, 30019, Republic of Korea
| | - Jonghyun Yoon
- National Institute of Environmental Research, Incheon, 22689, Republic of Korea
| | - Yuhoon Yeum
- Program in Environmental Technology and Policy, Korea University, Sejong, 30019, Republic of Korea
| | - Sunhwa Park
- National Institute of Environmental Research, Incheon, 22689, Republic of Korea
| | - Hyun-Koo Kim
- National Institute of Environmental Research, Incheon, 22689, Republic of Korea
| | - Moonsu Kim
- National Institute of Environmental Research, Incheon, 22689, Republic of Korea
| | - Hyen Mi Chung
- National Institute of Environmental Research, Incheon, 22689, Republic of Korea
| | - Sooyoul Kwon
- Department of Environmental Health, Korea National Open University, Seoul, 03087, Republic of Korea
| | - Seong-Taek Yun
- Department of Earth and Environmental Sciences and KU-KIST Green School, Korea University, Seoul, 02841, Republic of Korea
| | - Young Kim
- Department of Environmental Engineering, Korea University, Sejong, 30019, Republic of Korea; Program in Environmental Technology and Policy, Korea University, Sejong, 30019, Republic of Korea.
| |
Collapse
|
4
|
The diversity of sulfate-reducing bacteria in the seven bioreactors. Arch Microbiol 2018; 200:945-950. [PMID: 29610938 DOI: 10.1007/s00203-018-1510-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/27/2018] [Accepted: 03/29/2018] [Indexed: 10/17/2022]
Abstract
Anaerobic technology has a wide scope of application in different areas such as manufacturing, food industry, and agriculture. Nowadays, it is mainly used to produce electrical and thermal energy from crop processing, solid waste treatment or wastewater treatment. More intensively, trend nowadays is usage of this technology biodegradable and biomass waste processing and biomethane or hydrogen production. In this paper, the diversities of sulfate-reducing bacteria (SRB) under different imputed raw material to the bioreactors were characterized. These diversities at the beginning of sampling and after cultivation were compared. Desulfovibrio, Desulfobulbus, and Desulfomicrobium genus as dominant among sulfate reducers in the bioreactors were detected. The Desulfobulbus species were dominant among other SRB genera before cultivation, but these bacteria were detected only in three out of the seven bioreactors after cultivation dominant.
Collapse
|
5
|
Liu ZH, Yin H, Lin Z, Dang Z. Sulfate-reducing bacteria in anaerobic bioprocesses: basic properties of pure isolates, molecular quantification, and controlling strategies. ACTA ACUST UNITED AC 2018. [DOI: 10.1080/21622515.2018.1437783] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Ze-hua Liu
- School of Environment and Energy, South China University of Technology, Guangzhou, People’s Republic of China
- Key Lab Pollution Control and Ecosystem Restoration in Industry Cluster, Ministry of Education, Guangzhou, People’s Republic of China
- Guangdong Environmental Protection Key Laboratory of Solid Waste Treatment and Recycling, Guangzhou, People’s Republic of China
- Guangdong Provincial Engineering and Technology Research Center for Environment Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou, People’s Republic of China
| | - Hua Yin
- School of Environment and Energy, South China University of Technology, Guangzhou, People’s Republic of China
| | - Zhang Lin
- School of Environment and Energy, South China University of Technology, Guangzhou, People’s Republic of China
| | - Zhi Dang
- School of Environment and Energy, South China University of Technology, Guangzhou, People’s Republic of China
| |
Collapse
|
6
|
Reprint of: Contribution of enrichments and resampling for sulfate reducing bacteria diversity assessment by high-throughput cultivation. J Microbiol Methods 2017; 138:100-105. [PMID: 28571925 DOI: 10.1016/j.mimet.2017.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 01/07/2015] [Accepted: 01/07/2015] [Indexed: 11/20/2022]
Abstract
The development of new high-throughput cultivation methods aims to increase the isolation efficiency as compared to standard techniques that often require enrichment procedures to compensate the low microbial recovery. In the current study, estuarine sulfate-reducing bacteria were isolated using an anaerobic isolation procedure in 384-well microplates. Ninety-nine strains were recovered from initial sediments. Isolates were identified according to their partial 16S rRNA sequences and clustered into 13 phylotypes. Besides, the increase in species richness obtained through enrichments or resampling was investigated. Forty-four enrichment procedures were conducted and shifts in sulfate-reducing bacterial communities were investigated through dsrAB gene fingerprinting. Despite efforts in conducting numerous enrichment conditions only few of them were statistically different from initial sample. The cultural diversity obtained from 3 of the most divergent enrichments, as well as from resampled sediments equally contributed to raise the sulfate-reducing diversity up to 22 phylotypes. Enrichments (selection of metabolism) or resampling (transient populations and micro-heterogeneity) may still be helpful to assess new microbial phylotypes. Nevertheless, all the newly cultivated strains were all representatives of minor Operational Taxonomic Units and could eventually be recovered by maintaining high-throughput isolation effort from the initial sediments.
Collapse
|
7
|
da Silva SM, Amaral C, Neves SS, Santos C, Pimentel C, Rodrigues-Pousada C. An HcpR paralog of Desulfovibrio gigas provides protection against nitrosative stress. FEBS Open Bio 2015; 5:594-604. [PMID: 26273559 PMCID: PMC4534486 DOI: 10.1016/j.fob.2015.07.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 07/01/2015] [Indexed: 01/12/2023] Open
Abstract
Desulfovibrio gigas genome encodes two HcpR paralogs, HcpR1 and HcpR2. Cells lacking HcpR1 are less tolerant to NO. HcpR1 regulates the expression of several genes related to nitrogen metabolism. Phylogenetic analyses indicate that the presence of HcpR paralogs is a common finding among Desulfovibrio species.
Desulfovibrio gigas belongs to the group of sulfate reducing bacteria (SRB). These ubiquitous and metabolically versatile microorganisms are often exposed to reactive nitrogen species (RNS). Nonetheless, the mechanisms and regulatory elements involved in nitrosative stress protection are still poorly understood. The transcription factor HcpR has emerged as a putative regulator of nitrosative stress response among anaerobic bacteria. HcpR is known to orchestrate the expression of the hybrid cluster protein gene, hcp, proposed to be involved in cellular defense against RNS. According to phylogenetic analyses, the occurrence of hcpR paralog genes is a common feature among several Desulfovibrio species. Within the D. gigas genome we have identified two HcpR-related sequences. One of these sequences, hcpR1, was found in the close vicinity of the hcp gene and this finding prompted us to proceed with its functional characterization. We observed that the growth of a D. gigas strain lacking hcpR1 is severely impaired under nitrosative stress. An in silico search revealed several putative targets of HcpR1 that were experimentally validated. The fact that HcpR1 regulates several genes encoding proteins involved in nitrite and nitrate metabolism, together with the sensitive growth phenotype to NO displayed by an hcpR1 mutant strain, strongly supports a relevant role of this factor under nitrosative stress. Moreover, the finding that several Desulfovibrio species possess HcpR paralogs, which have been transmitted vertically in the evolution and diversification of the genus, suggests that these sequences may confer adaptive or survival advantage to these organisms, possibly by increasing their tolerance to nitrosative stress.
Collapse
Key Words
- BI, Bayesian inference
- BS, bootstrap
- CRP/FNR, cAMP receptor protein/fumarate and nitrate reductase regulatory protein
- Desulfovibrio
- Frdx, ferredoxin
- GSNO, S-nitrosoglutathione
- HGT, horizontal gene transfer
- Hcp, hybrid cluster protein
- HcpR
- ML, maximum likelihood
- MP, maximum parsimony
- Molecular phylogeny
- NO, nitric oxide
- Nitrosative stress
- PP, posterior probability
- RNS, reactive nitrogen species
- ROO, rubredoxin oxygen reductase
- SRB, sulfate reducing bacteria
- Sulfate reducing bacteria
- Transcription regulation
Collapse
Affiliation(s)
- Sofia M da Silva
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Catarina Amaral
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Susana S Neves
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Cátia Santos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Catarina Pimentel
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Claudina Rodrigues-Pousada
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| |
Collapse
|
8
|
Colin Y, Goñi-Urriza M, Caumette P, Guyoneaud R. Contribution of enrichments and resampling for sulfate reducing bacteria diversity assessment by high-throughput cultivation. J Microbiol Methods 2015; 110:92-7. [PMID: 25578508 DOI: 10.1016/j.mimet.2015.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 01/07/2015] [Accepted: 01/07/2015] [Indexed: 10/24/2022]
Abstract
The development of new high-throughput cultivation methods aims to increase the isolation efficiency as compared to standard techniques that often require enrichment procedures to compensate the low microbial recovery. In the current study, estuarine sulfate-reducing bacteria were isolated using an anaerobic isolation procedure in 384-well microplates. Ninety-nine strains were recovered from initial sediments. Isolates were identified according to their partial 16S rRNA sequences and clustered into 13 phylotypes. Besides, the increase in species richness obtained through enrichments or resampling was investigated. Forty-four enrichment procedures were conducted and shifts in sulfate-reducing bacterial communities were investigated through dsrAB gene fingerprinting. Despite efforts in conducting numerous enrichment conditions only few of them were statistically different from initial sample. The cultural diversity obtained from 3 of the most divergent enrichments, as well as from resampled sediments equally contributed to raise the sulfate-reducing diversity up to 22 phylotypes. Enrichments (selection of metabolism) or resampling (transient populations and micro-heterogeneity) may still be helpful to assess new microbial phylotypes. Nevertheless, all the newly cultivated strains were all representatives of minor Operational Taxonomic Units and could eventually be recovered by maintaining high-throughput isolation effort from the initial sediments.
Collapse
Affiliation(s)
- Yannick Colin
- Equipe Environnement et Microbiologie, IPREM UMR CNRS 5254, Université de Pau et des Pays de l'Adour, IBEAS, BP 1155, 64013 Pau Cedex, France
| | - Marisol Goñi-Urriza
- Equipe Environnement et Microbiologie, IPREM UMR CNRS 5254, Université de Pau et des Pays de l'Adour, IBEAS, BP 1155, 64013 Pau Cedex, France
| | - Pierre Caumette
- Equipe Environnement et Microbiologie, IPREM UMR CNRS 5254, Université de Pau et des Pays de l'Adour, IBEAS, BP 1155, 64013 Pau Cedex, France
| | - Rémy Guyoneaud
- Equipe Environnement et Microbiologie, IPREM UMR CNRS 5254, Université de Pau et des Pays de l'Adour, IBEAS, BP 1155, 64013 Pau Cedex, France.
| |
Collapse
|
9
|
Population Analysis of Mesophilic Microbial Fuel Cells Fed with Carbon Monoxide. Appl Biochem Biotechnol 2013; 172:713-26. [DOI: 10.1007/s12010-013-0556-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 09/26/2013] [Indexed: 11/25/2022]
|
10
|
Aulenta F, Catapano L, Snip L, Villano M, Majone M. Linking bacterial metabolism to graphite cathodes: electrochemical insights into the H(2) -producing capability of Desulfovibrio sp. CHEMSUSCHEM 2012; 5:1080-1085. [PMID: 22581429 DOI: 10.1002/cssc.201100720] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 01/19/2012] [Indexed: 05/31/2023]
Abstract
Microbial biocathodes allow converting and storing electricity produced from renewable sources in chemical fuels (e.g., H(2) ) and are, therefore, attracting considerable attention as alternative catalysts to more expensive and less available noble metals (notably Pt). Microbial biocathodes for H(2) production rely on the ability of hydrogenase-possessing microorganisms to catalyze proton reduction, with a solid electrode serving as direct electron donor. This study provides new chemical and electrochemical data on the bioelectrocatalytic activity of Desulfovibrio species. A combination of chronoamperometry, cyclic voltammetry, and impedance spectroscopy tests were used to assess the performance of the H(2) -producing microbial biocathode and to shed light on the involved electron transfer mechanisms. Cells attached onto a graphite electrode were found to catalyze H(2) production for cathode potentials more reducing than -900 mV vs. standard hydrogen electrode. The highest obtained H(2) production was 8 mmol L(-1) per day, with a Coulombic efficiency close to 100 %. The electrochemical performance of the biocathode changed over time probably due to the occurrence of enzyme activation processes induced by extended electrode polarization. Remarkably, H(2) (at least up to 20 % v/v) was not found to significantly inhibit its own production.
Collapse
Affiliation(s)
- Federico Aulenta
- Department of Chemistry, Sapienza University of Rome, P.Le Aldo Moro 5, 00185 Rome, Italy.
| | | | | | | | | |
Collapse
|
11
|
van Houten BHGW, van Doesburg W, Dijkman H, Copini C, Smidt H, Stams AJM. Long-term performance and microbial community analysis of a full-scale synthesis gas fed reactor treating sulfate- and zinc-rich wastewater. Appl Microbiol Biotechnol 2009; 84:555-63. [PMID: 19543724 PMCID: PMC2729981 DOI: 10.1007/s00253-009-2075-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 06/04/2009] [Accepted: 06/04/2009] [Indexed: 11/28/2022]
Abstract
The performance of a full-scale (500 m3) sulfidogenic synthesis gas fed gas-lift reactor treating metal- and sulfate-rich wastewater was investigated over a period of 128 weeks. After startup, the reactor had a high methanogenic activity of 46 Nm3·h−1. Lowering the carbon dioxide feed rate during the first 6 weeks gradually lowered the methane production rate. Between weeks 8 and 93, less than 1% of the hydrogen supplied was used for methanogenesis. Denaturing gradient gel electrophoresis analysis of polymerase chain reaction-amplified 16S rRNA gene fragments showed that the archaeal community decreased in diversity but did not disappear completely. After the carbon dioxide feed rate increased in week 88, the methane production rate also increased, confirming that methane production was carbon dioxide limited. Even though lowering the carbon dioxide feed appeared to affect part of the sulfate-reducing community, it did not prevent achieving the desired rates of sulfate reduction. The average sulfate conversion rate was 181 kg∙h−1 for the first 92 weeks. After 92 weeks, the sulfate input rate was increased and from week 94 to 128, the average weekly sulfate conversion rate was 295 kg·h−1 (SD ± 87). Even higher sulfate conversion rates of up to 400 kg·h−1 could be sustained for weeks 120–128. The long-term performance and stability together with the ability to control methanogenesis demonstrates that synthesis gas fed reactor can be used successfully at full scale to treat metal and sulfate-rich wastewater.
Collapse
|