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Cui S, Wang R, Chen Q, Pugliese L, Wu S. Geobatteries in environmental biogeochemistry: Electron transfer and utilization. ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY 2024; 22:100446. [PMID: 39104555 PMCID: PMC11298864 DOI: 10.1016/j.ese.2024.100446] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 06/29/2024] [Accepted: 06/30/2024] [Indexed: 08/07/2024]
Abstract
The efficiency of direct electron flow from electron donors to electron acceptors in redox reactions is significantly influenced by the spatial separation of these components. Geobatteries, a class of redox-active substances naturally present in soil-water systems, act as electron reservoirs, reversibly donating, storing, and accepting electrons. This capability allows the temporal and spatial decoupling of redox half-reactions, providing a flexible electron transfer mechanism. In this review, we systematically examine the critical role of geobatteries in influencing electron transfer and utilization in environmental biogeochemical processes. Typical redox-active centers within geobatteries, such as quinone-like moieties, nitrogen- and sulfur-containing groups, and variable-valent metals, possess the potential to repeatedly charge and discharge. Various characterization techniques, ranging from qualitative methods like elemental analysis, imaging, and spectroscopy, to quantitative techniques such as chemical, spectroscopic, and electrochemical methods, have been developed to evaluate this reversible electron transfer capacity. Additionally, current research on the ecological and environmental significance of geobatteries extends beyond natural soil-water systems (e.g., soil carbon cycle) to engineered systems such as water treatment (e.g., nitrogen removal) and waste management (e.g., anaerobic digestion). Despite these advancements, challenges such as the complexity of environmental systems, difficulties in accurately quantifying electron exchange capacity, and scaling-up issues must be addressed to fully unlock their potential. This review underscores both the promise and challenges associated with geobatteries in responding to environmental issues, such as climate change and pollutant transformation.
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Affiliation(s)
- Shihao Cui
- Department of Agroecology, Aarhus University, Blichers Allé 20, 8830, Tjele, Denmark
| | - Rui Wang
- Department of Biological and Chemical Engineering, Aarhus University, Gustav Wieds Vej 10, 8000, Aarhus, Denmark
| | - Qing Chen
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Lorenzo Pugliese
- Department of Agroecology, Aarhus University, Blichers Allé 20, 8830, Tjele, Denmark
| | - Shubiao Wu
- Department of Agroecology, Aarhus University, Blichers Allé 20, 8830, Tjele, Denmark
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2
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Hoover RL, Keffer JL, Polson SW, Chan CS. Gallionellaceae pangenomic analysis reveals insight into phylogeny, metabolic flexibility, and iron oxidation mechanisms. mSystems 2023; 8:e0003823. [PMID: 37882557 PMCID: PMC10734462 DOI: 10.1128/msystems.00038-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 09/20/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE Neutrophilic iron-oxidizing bacteria (FeOB) produce copious iron (oxyhydr)oxides that can profoundly influence biogeochemical cycles, notably the fate of carbon and many metals. To fully understand environmental microbial iron oxidation, we need a thorough accounting of iron oxidation mechanisms. In this study, we show the Gallionellaceae FeOB genomes encode both characterized iron oxidases as well as uncharacterized multiheme cytochromes (MHCs). MHCs are predicted to transfer electrons from extracellular substrates and likely confer metabolic capabilities that help Gallionellaceae occupy a range of different iron- and mineral-rich niches. Gallionellaceae appear to specialize in iron oxidation, so it would be advantageous for them to have multiple mechanisms to oxidize various forms of iron, given the many iron minerals on Earth, as well as the physiological and kinetic challenges faced by FeOB. The multiple iron/mineral oxidation mechanisms may help drive the widespread ecological success of Gallionellaceae.
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Affiliation(s)
- Rene L. Hoover
- Microbiology Graduate Program, University of Delaware, Newark, Delaware, USA
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
| | - Jessica L. Keffer
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
| | - Shawn W. Polson
- Department of Computer and Information Sciences, University of Delaware, Newark, Delaware, USA
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, USA
| | - Clara S. Chan
- Microbiology Graduate Program, University of Delaware, Newark, Delaware, USA
- Department of Earth Sciences, University of Delaware, Newark, Delaware, USA
- School of Marine Science and Policy, University of Delaware, Newark, Delaware, USA
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3
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Zhang Y, O'Loughlin EJ, Park SY, Kwon MJ. Effects of Fe(III) (hydr)oxide mineralogy on the development of microbial communities originating from soil, surface water, groundwater, and aerosols. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:166993. [PMID: 37717756 DOI: 10.1016/j.scitotenv.2023.166993] [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: 07/03/2023] [Revised: 09/09/2023] [Accepted: 09/09/2023] [Indexed: 09/19/2023]
Abstract
Microbial Fe(III) reduction is a key component of the iron cycle in natural environments. However, the susceptibility of Fe(III) (hydr)oxides to microbial reduction varies depending on the mineral's crystallinity, and the type of Fe(III) (hydr)oxide in turn will affect the composition of the microbial community. We created microcosm reactors with microbial communities from four different sources (soil, surface water, groundwater, and aerosols), three Fe(III) (hydr)oxides (lepidocrocite, goethite, and hematite) as electron acceptors, and acetate as an electron donor to investigate the shaping effect of Fe(III) mineral type on the development of microbial communities. During a 10-month incubation, changes in microbial community composition, Fe(III) reduction, and acetate utilization were monitored. Overall, there was greater reduction of lepidocrocite than of goethite and hematite, and the development of microbial communities originating from the same source diverged when supplied with different Fe(III) (hydr)oxides. Furthermore, each Fe(III) mineral was associated with unique taxa that emerged from different sources. This study illustrates the taxonomic diversity of Fe(III)-reducing microbes from a broad range of natural environments.
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Affiliation(s)
- Yidan Zhang
- Department of Earth and Environmental Sciences, Korea University, Seoul 02841, South Korea
| | - Edward J O'Loughlin
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States
| | - Su-Young Park
- Department of Earth and Environmental Sciences, Korea University, Seoul 02841, South Korea
| | - Man Jae Kwon
- Department of Earth and Environmental Sciences, Korea University, Seoul 02841, South Korea.
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4
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Liang ZH, Sun H, Li Y, Hu A, Tang Q, Yu HQ. Enforcing energy consumption promotes microbial extracellular respiration for xenobiotic bioconversion. Environ Microbiol 2023; 25:2943-2957. [PMID: 37602917 DOI: 10.1111/1462-2920.16484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 08/08/2023] [Indexed: 08/22/2023]
Abstract
Extracellular electron transfer (EET) empowers electrogens to catalyse the bioconversion of a wide range of xenobiotics in the environment. Synthetic bioengineering has proven effective in promoting EET output. However, conventional strategies mainly focus on modifications of EET-related genes or pathways, which leads to a bottleneck due to the intricate nature of electrogenic metabolic properties and intricate pathway regulation that remain unelucidated. Herein, we propose a novel EET pathway-independent approach, from an energy manipulation perspective, to enhance microbial EET output. The Controlled Hydrolyzation of ATP to Enhance Extracellular Respiration (CHEER) strategy promotes energy utilization and persistently reduces the intracellular ATP level in Shewanella oneidensis, a representative electrogenic microbe. This approach leads to the accelerated consumption of carbon substrate, increased biomass accumulation and an expanded intracellular NADH pool. Both microbial electrolysis cell and microbial fuel cell tests exhibit that the CHEER strain substantially enhances EET capability. Analysis of transcriptome profiles reveals that the CHEER strain considerably bolsters biomass synthesis and metabolic activity. When applied to the bioconversion of model xenobiotics including methyl orange, Cr(VI) and U(VI), the CHEER strain consistently exhibits enhanced removal efficiencies. This work provides a new perspective and a feasible strategy to enhance microbial EET for efficient xenobiotic conversion.
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Affiliation(s)
- Zi-Han Liang
- Department of Environmental Science and Technology, University of Science and Technology of China, Hefei, China
| | - Hong Sun
- CAS Key Laboratory of Urban Pollutant Conversion, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Yang Li
- CAS Key Laboratory of Urban Pollutant Conversion, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Anyi Hu
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
| | - Qiang Tang
- Department of Environmental Science and Technology, University of Science and Technology of China, Hefei, China
| | - Han-Qing Yu
- Department of Environmental Science and Technology, University of Science and Technology of China, Hefei, China
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5
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Olmsted CN, Ort R, Tran PQ, McDaniel EA, Roden EE, Bond DR, He S, McMahon KD. Environmental predictors of electroactive bacterioplankton in small boreal lakes. Environ Microbiol 2023; 25:705-720. [PMID: 36529539 DOI: 10.1111/1462-2920.16314] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Extracellular electron transfer (EET) by electroactive bacteria in anoxic soils and sediments is an intensively researched subject, but EET's function in planktonic ecology has been less considered. Following the discovery of an unexpectedly high prevalence of EET genes in a bog lake's bacterioplankton, we hypothesized that the redox capacities of dissolved organic matter (DOM) enrich for electroactive bacteria by mediating redox chemistry. We developed the bioinformatics pipeline FEET (Find EET) to identify and summarize predicted EET protein-encoding genes from metagenomics data. We then applied FEET to 36 bog and thermokarst lakes and correlated gene occurrence with environmental data to test our predictions. Our results provide indirect evidence that DOM may participate in bacterioplankton EET. We found a similarly high prevalence of genes encoding putative EET proteins in most of these lakes, where oxidative EET strongly correlated with DOM. Numerous novel clusters of multiheme cytochromes that may enable EET were identified. Taxa previously not considered EET-capable were found to carry EET genes. We propose that EET and DOM interactions are of ecologically important to bacterioplankton in small boreal lakes, and that EET, particularly by methylotrophs and anoxygenic phototrophs, should be further studied and incorporated into methane emission models of melting permafrost.
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Affiliation(s)
- Charles N Olmsted
- Department of Molecular and Environmental Toxicology, University of Wisconsin - Madison, Madison, Wisconsin, USA
- Trout Lake Station, Center for Limnology, University of Wisconsin - Madison, Boulder, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Roger Ort
- Trout Lake Station, Center for Limnology, University of Wisconsin - Madison, Boulder, Wisconsin, USA
| | - Patricia Q Tran
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin, USA
- Department of Integrative Biology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Elizabeth A McDaniel
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Eric E Roden
- Department of Geoscience, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Daniel R Bond
- Department of Plant and Microbial Biology and BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, USA
| | - Shaomei He
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Katherine D McMahon
- Department of Bacteriology, University of Wisconsin - Madison, Madison, Wisconsin, USA
- Department of Civil and Environmental Engineering, University of Wisconsin - Madison, Madison, Wisconsin, USA
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6
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Luo X, Huang L, Cai X, Zhou L, Zhou S, Yuan Y. Structure and core taxa of bacterial communities involved in extracellular electron transfer in paddy soils across China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 844:157196. [PMID: 35810886 DOI: 10.1016/j.scitotenv.2022.157196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/25/2022] [Accepted: 07/02/2022] [Indexed: 06/15/2023]
Abstract
Microbial communities with extracellular electron transfer (EET) activity are capable of driving geochemical changes and cycles, but a comprehensive understanding of the key microbiota responsible for EET in complex soil matrices is still lacking. Herein, the EET activities, in terms of maximum current density (jmax) and accumulated charge output (Cout), of 41 paddy soils across China were evaluated from the exoelectrogenic properties with a conventional bioelectrochemical system (BES). The jmax with a range of 8.85 × 10-4 to 0.41 A/m2 and Cout with a range of 0.27 to 172.21C were obtained from these soil-based BESs. The bacterial community analyses revealed that the most abundant phylum, order, and genus were Firmicutes, Clostridiales, and Clostridum-sensus-stricto 10, respectively. Bacterial network analysis displayed the positive correlations between the majority of electroactive bacteria-containing genera and multiple other genera, indicating their underlying cooperation for the EET. Partial least squares regression (PLSR) model showed remarkable performance in describing the EET activity with 75 most abundant genera as input variables, identified that 32 genera were very important for governing the EET activities. Multiple linear regression (MLR) analyses further prioritized that the genera norank-c-Berkelbacteria and Fonticella were the key contributors, while the genus Paenibacillus was the key competitor against bacterial exoelectrogenesis in paddy soils. Moreover, the spearman analysis showed that the abundance of these keystone taxa was mainly influenced by the carbon content and pH. This approach provides a promising avenue to monitor the microbial activities in paddy soils as well as the links between microbial community composition and ecological function.
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Affiliation(s)
- Xiaoshan Luo
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Lingyan Huang
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Xixi Cai
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Lihua Zhou
- Department of Pharmaceutical Engineering, School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, School of Resources and Environment, Fujian Agriculture and Forestry, Fuzhou 350000, China
| | - Yong Yuan
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China.
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7
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Berger S, Shaw DR, Berben T, Ouboter HT, In 't Zandt MH, Frank J, Reimann J, Jetten MSM, Welte CU. Current production by non-methanotrophic bacteria enriched from an anaerobic methane-oxidizing microbial community. Biofilm 2021; 3:100054. [PMID: 34308332 PMCID: PMC8258643 DOI: 10.1016/j.bioflm.2021.100054] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/12/2021] [Accepted: 05/19/2021] [Indexed: 12/21/2022] Open
Abstract
In recent years, the externalization of electrons as part of respiratory metabolic processes has been discovered in many different bacteria and some archaea. Microbial extracellular electron transfer (EET) plays an important role in many anoxic natural or engineered ecosystems. In this study, an anaerobic methane-converting microbial community was investigated with regard to its potential to perform EET. At this point, it is not well-known if or how EET confers a competitive advantage to certain species in methane-converting communities. EET was investigated in a two-chamber electrochemical system, sparged with methane and with an applied potential of +400 mV versus standard hydrogen electrode. A biofilm developed on the working electrode and stable low-density current was produced, confirming that EET indeed did occur. The appearance and presence of redox centers at −140 to −160 mV and at −230 mV in the biofilm was confirmed by cyclic voltammetry scans. Metagenomic analysis and fluorescence in situ hybridization of the biofilm showed that the anaerobic methanotroph ‘Candidatus Methanoperedens BLZ2’ was a significant member of the biofilm community, but its relative abundance did not increase compared to the inoculum. On the contrary, the relative abundance of other members of the microbial community significantly increased (up to 720-fold, 7.2% of mapped reads), placing these microorganisms among the dominant species in the bioanode community. This group included Zoogloea sp., Dechloromonas sp., two members of the Bacteroidetes phylum, and the spirochete Leptonema sp. Genes encoding proteins putatively involved in EET were identified in Zoogloea sp., Dechloromonas sp. and one member of the Bacteroidetes phylum. We suggest that instead of methane, alternative carbon sources such as acetate were the substrate for EET. Hence, EET in a methane-driven chemolithoautotrophic microbial community seems a complex process in which interactions within the microbial community are driving extracellular electron transfer to the electrode.
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Affiliation(s)
- S Berger
- Institute for Water and Wetland Research, Department of Microbiology, Radboud University, Nijmegen, the Netherlands
| | - D R Shaw
- Biological and Environmental Science and Engineering Division, Water Desalination and Reuse Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Soehngen Institute of Anaerobic Microbiology, Radboud University, Nijmegen, the Netherlands
| | - T Berben
- Institute for Water and Wetland Research, Department of Microbiology, Radboud University, Nijmegen, the Netherlands
| | - H T Ouboter
- Institute for Water and Wetland Research, Department of Microbiology, Radboud University, Nijmegen, the Netherlands.,Soehngen Institute of Anaerobic Microbiology, Radboud University, Nijmegen, the Netherlands
| | - M H In 't Zandt
- Institute for Water and Wetland Research, Department of Microbiology, Radboud University, Nijmegen, the Netherlands.,Netherlands Earth System Science Center, Utrecht University, Utrecht, the Netherlands
| | - J Frank
- Institute for Water and Wetland Research, Department of Microbiology, Radboud University, Nijmegen, the Netherlands.,Soehngen Institute of Anaerobic Microbiology, Radboud University, Nijmegen, the Netherlands
| | - J Reimann
- Institute for Water and Wetland Research, Department of Microbiology, Radboud University, Nijmegen, the Netherlands
| | - M S M Jetten
- Institute for Water and Wetland Research, Department of Microbiology, Radboud University, Nijmegen, the Netherlands.,Netherlands Earth System Science Center, Utrecht University, Utrecht, the Netherlands.,Soehngen Institute of Anaerobic Microbiology, Radboud University, Nijmegen, the Netherlands
| | - C U Welte
- Institute for Water and Wetland Research, Department of Microbiology, Radboud University, Nijmegen, the Netherlands.,Soehngen Institute of Anaerobic Microbiology, Radboud University, Nijmegen, the Netherlands
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8
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Comprehensive dataset of shotgun metagenomes from oxygen stratified freshwater lakes and ponds. Sci Data 2021; 8:131. [PMID: 33990618 PMCID: PMC8121793 DOI: 10.1038/s41597-021-00910-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 03/29/2021] [Indexed: 11/20/2022] Open
Abstract
Stratified lakes and ponds featuring steep oxygen gradients are significant net sources of greenhouse gases and hotspots in the carbon cycle. Despite their significant biogeochemical roles, the microbial communities, especially in the oxygen depleted compartments, are poorly known. Here, we present a comprehensive dataset including 267 shotgun metagenomes from 41 stratified lakes and ponds mainly located in the boreal and subarctic regions, but also including one tropical reservoir and one temperate lake. For most lakes and ponds, the data includes a vertical sample set spanning from the oxic surface to the anoxic bottom layer. The majority of the samples were collected during the open water period, but also a total of 29 samples were collected from under the ice. In addition to the metagenomic sequences, the dataset includes environmental variables for the samples, such as oxygen, nutrient and organic carbon concentrations. The dataset is ideal for further exploring the microbial taxonomic and functional diversity in freshwater environments and potential climate change impacts on the functioning of these ecosystems. Measurement(s) | Metagenome | Technology Type(s) | DNA sequencing | Factor Type(s) | lake | Sample Characteristic - Environment | lake with an anoxic hypolimnion • freshwater biome | Sample Characteristic - Location | Sweden • Finland • Canada • Switzerland • Commonwealth of Puerto Rico |
Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.14191043
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9
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Rissanen AJ, Saarela T, Jäntti H, Buck M, Peura S, Aalto SL, Ojala A, Pumpanen J, Tiirola M, Elvert M, Nykänen H. Vertical stratification patterns of methanotrophs and their genetic controllers in water columns of oxygen-stratified boreal lakes. FEMS Microbiol Ecol 2021; 97:fiaa252. [PMID: 33316049 PMCID: PMC7840105 DOI: 10.1093/femsec/fiaa252] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 12/10/2020] [Indexed: 11/20/2022] Open
Abstract
The vertical structuring of methanotrophic communities and its genetic controllers remain understudied in the water columns of oxygen-stratified lakes. Therefore, we used 16S rRNA gene sequencing to study the vertical stratification patterns of methanotrophs in two boreal lakes, Lake Kuivajärvi and Lake Lovojärvi. Furthermore, metagenomic analyses were performed to assess the genomic characteristics of methanotrophs in Lovojärvi and the previously studied Lake Alinen Mustajärvi. The methanotroph communities were vertically structured along the oxygen gradient. Alphaproteobacterial methanotrophs preferred oxic water layers, while Methylococcales methanotrophs, consisting of putative novel genera and species, thrived, especially at and below the oxic-anoxic interface and showed distinct depth variation patterns, which were not completely predictable by their taxonomic classification. Instead, genomic differences among Methylococcales methanotrophs explained their variable vertical depth patterns. Genes in clusters of orthologous groups (COG) categories L (replication, recombination and repair) and S (function unknown) were relatively high in metagenome-assembled genomes representing Methylococcales clearly thriving below the oxic-anoxic interface, suggesting genetic adaptations for increased stress tolerance enabling living in the hypoxic/anoxic conditions. By contrast, genes in COG category N (cell motility) were relatively high in metagenome-assembled genomes of Methylococcales thriving at the oxic-anoxic interface, which suggests genetic adaptations for increased motility at the vertically fluctuating oxic-anoxic interface.
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Affiliation(s)
- Antti J Rissanen
- Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 6, FI-33720, Tampere, Finland
| | - Taija Saarela
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
| | - Helena Jäntti
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
| | - Moritz Buck
- Department of Ecology and Genetics/Limnology, Uppsala University, Norbyvägen 18D, SE-75236, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, box 7050, SE-75007, Uppsala, Sweden
| | - Sari Peura
- Department of Forest Mycology and Plant Pathology, Science for Life Laboratory, Swedish University of Agricultural Sciences, Almas allé 5, SE-75651, Uppsala, Sweden
| | - Sanni L Aalto
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
- Department of Biological and Environmental Sciences, University of Jyväskylä, Survontie 9 C, FI-40014, Jyväskylä, Finland
| | - Anne Ojala
- Ecosystems and Environment Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 1, FI-00014, Helsinki, Finland
- Institute of Atmospheric and Earth System Research (INAR)/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Viikinkaari 1, FI-00014, Helsinki, Finland
| | - Jukka Pumpanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
| | - Marja Tiirola
- Department of Biological and Environmental Sciences, University of Jyväskylä, Survontie 9 C, FI-40014, Jyväskylä, Finland
| | - Marcus Elvert
- MARUM - Center for Marine Environmental Sciences & Faculty of Geosciences, University of Bremen, Leobener Str. 8, D-28359, Bremen, Germany
| | - Hannu Nykänen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
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10
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Tsuji JM, Tran N, Schiff SL, Venkiteswaran JJ, Molot LA, Tank M, Hanada S, Neufeld JD. Anoxygenic photosynthesis and iron-sulfur metabolic potential of Chlorobia populations from seasonally anoxic Boreal Shield lakes. THE ISME JOURNAL 2020; 14:2732-2747. [PMID: 32747714 PMCID: PMC7784702 DOI: 10.1038/s41396-020-0725-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/02/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022]
Abstract
Aquatic environments with high levels of dissolved ferrous iron and low levels of sulfate serve as an important systems for exploring biogeochemical processes relevant to the early Earth. Boreal Shield lakes, which number in the tens of millions globally, commonly develop seasonally anoxic waters that become iron rich and sulfate poor, yet the iron-sulfur microbiology of these systems has been poorly examined. Here we use genome-resolved metagenomics and enrichment cultivation to explore the metabolic diversity and ecology of anoxygenic photosynthesis and iron/sulfur cycling in the anoxic water columns of three Boreal Shield lakes. We recovered four high-completeness and low-contamination draft genome bins assigned to the class Chlorobia (formerly phylum Chlorobi) from environmental metagenome data and enriched two novel sulfide-oxidizing species, also from the Chlorobia. The sequenced genomes of both enriched species, including the novel "Candidatus Chlorobium canadense", encoded the cyc2 gene that is associated with photoferrotrophy among cultured Chlorobia members, along with genes for phototrophic sulfide oxidation. One environmental genome bin also encoded cyc2. Despite the presence of cyc2 in the corresponding draft genome, we were unable to induce photoferrotrophy in "Ca. Chlorobium canadense". Genomic potential for phototrophic sulfide oxidation was more commonly detected than cyc2 among environmental genome bins of Chlorobia, and metagenome and cultivation data suggested the potential for cryptic sulfur cycling to fuel sulfide-based growth. Overall, our results provide an important basis for further probing the functional role of cyc2 and indicate that anoxygenic photoautotrophs in Boreal Shield lakes could have underexplored photophysiology pertinent to understanding Earth's early microbial communities.
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Affiliation(s)
- J M Tsuji
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - N Tran
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - S L Schiff
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - J J Venkiteswaran
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
- Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON, N2L 3C5, Canada
| | - L A Molot
- York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
| | - M Tank
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures GmbH, Inhoffenstrasse 7B, 38124, Braunschweig, Germany
- Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 192-0397, Japan
| | - S Hanada
- Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 192-0397, Japan
| | - J D Neufeld
- University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada.
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11
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Bhattacharya S, Roy C, Mandal S, Sarkar J, Rameez MJ, Mondal N, Mapder T, Chatterjee S, Pyne P, Alam M, Haldar PK, Roy R, Fernandes S, Peketi A, Chakraborty R, Mazumdar A, Ghosh W. Aerobic microbial communities in the sediments of a marine oxygen minimum zone. FEMS Microbiol Lett 2020; 367:5911577. [PMID: 32975580 PMCID: PMC7568448 DOI: 10.1093/femsle/fnaa157] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 09/23/2020] [Indexed: 12/20/2022] Open
Abstract
The ecology of aerobic microorganisms is never explored in marine oxygen minimum zone (OMZ) sediments. Here we reveal aerobic bacterial communities along ∼3 m sediment-horizons of the eastern Arabian Sea OMZ. Sulfide-containing sediment-cores retrieved from 530 mbsl (meters beneath the sea-level) and 580 mbsl were explored at 15–30 cm intervals, using metagenomics, pure-culture-isolation, genomics and metatranscriptomics. Genes for aerobic respiration, and oxidation of methane/ammonia/alcohols/thiosulfate/sulfite/organosulfur-compounds, were detected in the metagenomes from all 25 sediment-samples explored. Most probable numbers for aerobic chemolithoautotrophs and chemoorganoheterotrophs at individual sample-sites were up to 1.1 × 107 (g sediment)-1. The sediment-sample collected from 275 cmbsf (centimeters beneath the seafloor) of the 530-mbsl-core yielded many such obligately aerobic isolates belonging to Cereibacter, Guyparkeria, Halomonas, Methylophaga, Pseudomonas and Sulfitobacter which died upon anaerobic incubation, despite being provided with all possible electron acceptors and fermentative substrates. High percentages of metatranscriptomic reads from the 275 cmbsf sediment-sample, and metagenomic reads from all 25 sediment-samples, matched the isolates’ genomic sequences including those for aerobic metabolisms, genetic/environmental information processing and cell division, thereby illustrating the bacteria's in-situ activity, and ubiquity across the sediment-horizons, respectively. The findings hold critical implications for organic carbon sequestration/remineralization, and inorganic compounds oxidation, within the sediment realm of global marine OMZs.
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Affiliation(s)
| | - Chayan Roy
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Subhrangshu Mandal
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Jagannath Sarkar
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Moidu Jameela Rameez
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Nibendu Mondal
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Tarunendu Mapder
- Department of Chemistry, Bose Institute, 93/1 APC Road, Kolkata 700009, India
| | - Sumit Chatterjee
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Prosenjit Pyne
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Masrure Alam
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Prabir Kumar Haldar
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Rimi Roy
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Svetlana Fernandes
- Gas Hydrate Research Group, Geological Oceanography, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India
| | - Aditya Peketi
- Gas Hydrate Research Group, Geological Oceanography, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India
| | - Ranadhir Chakraborty
- Department of Biotechnology, University of North Bengal, Raja Rammohanpur, District - Darjeeling, West Bengal 734013, India
| | - Aninda Mazumdar
- Gas Hydrate Research Group, Geological Oceanography, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India
| | - Wriddhiman Ghosh
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
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12
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St James AR, Yavitt JB, Zinder SH, Richardson RE. Linking microbial Sphagnum degradation and acetate mineralization in acidic peat bogs: from global insights to a genome-centric case study. ISME JOURNAL 2020; 15:293-303. [PMID: 32951020 DOI: 10.1038/s41396-020-00782-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 09/09/2020] [Accepted: 09/14/2020] [Indexed: 11/09/2022]
Abstract
Ombrotrophic bogs accumulate large stores of soil carbon that eventually decompose to carbon dioxide and methane. Carbon accumulates because Sphagnum mosses slow microbial carbon decomposition processes, leading to the production of labile intermediate compounds. Acetate is a major product of Sphagnum degradation, yet rates of hydrogenotrophic methanogenesis far exceed rates of aceticlastic methanogenesis, suggesting that alternative acetate mineralization processes exist. Two possible explanations are aerobic respiration and anaerobic respiration via humic acids as electron acceptors. While these processes have been widely observed, microbial community interactions linking Sphagnum degradation and acetate mineralization remain cryptic. In this work, we use ordination and network analysis of functional genes from 110 globally distributed peatland metagenomes to identify conserved metabolic pathways in Sphagnum bogs. We then use metagenome-assembled genomes (MAGs) from McLean Bog, a Sphagnum bog in New York State, as a local case study to reconstruct pathways of Sphagnum degradation and acetate mineralization. We describe metabolically flexible Acidobacteriota MAGs that contain all genes to completely degrade Sphagnum cell wall sugars under both aerobic and anaerobic conditions. Finally, we propose a hypothetical model of acetate oxidation driven by changes in peat redox potential that explain how bogs may circumvent aceticlastic methanogenesis through aerobic and humics-driven respiration.
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Affiliation(s)
- Andrew R St James
- School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, USA.
| | - Joseph B Yavitt
- Department of Natural Resources, Cornell University, Ithaca, NY, USA
| | | | - Ruth E Richardson
- School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, USA
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13
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Chaput G, Billings AF, DeDiego L, Orellana R, Adkins JN, Nicora CD, Kim YM, Chu R, Simmons B, DeAngelis KM. Lignin induced iron reduction by novel sp., Tolumonas lignolytic BRL6-1. PLoS One 2020; 15:e0233823. [PMID: 32941430 PMCID: PMC7497984 DOI: 10.1371/journal.pone.0233823] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 08/26/2020] [Indexed: 11/19/2022] Open
Abstract
Lignin is the second most abundant carbon polymer on earth and despite having more fuel value than cellulose, it currently is considered a waste byproduct in many industrial lignocellulose applications. Valorization of lignin relies on effective and green methods of de-lignification, with a growing interest in the use of microbes. Here we investigate the physiology and molecular response of the novel facultative anaerobic bacterium, Tolumonas lignolytica BRL6-1, to lignin under anoxic conditions. Physiological and biochemical changes were compared between cells grown anaerobically in either lignin-amended or unamended conditions. In the presence of lignin, BRL6-1 accumulates higher biomass and has a shorter lag phase compared to unamended conditions, and 14% of the proteins determined to be significantly higher in abundance by log2 fold-change of 2 or greater were related to Fe(II) transport in late logarithmic phase. Ferrozine assays of the supernatant confirmed that Fe(III) was bound to lignin and reduced to Fe(II) only in the presence of BRL6-1, suggesting redox activity by the cells. LC-MS/MS analysis of the secretome showed an extra band at 20 kDa in lignin-amended conditions. Protein sequencing of this band identified a protein of unknown function with homology to enzymes in the radical SAM superfamily. Expression of this protein in lignin-amended conditions suggests its role in radical formation. From our findings, we suggest that BRL6-1 is using a protein in the radical SAM superfamily to interact with the Fe(III) bound to lignin and reducing it to Fe(II) for cellular use, increasing BRL6-1 yield under lignin-amended conditions. This interaction potentially generates organic free radicals and causes a radical cascade which could modify and depolymerize lignin. Further research should clarify the extent to which this mechanism is similar to previously described aerobic chelator-mediated Fenton chemistry or radical producing lignolytic enzymes, such as lignin peroxidases, but under anoxic conditions.
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Affiliation(s)
- Gina Chaput
- Department of Microbiology, University of Massachusetts–Amherst, Amherst, MA, United States of America
| | - Andrew F. Billings
- Department of Microbiology, University of Massachusetts–Amherst, Amherst, MA, United States of America
| | - Lani DeDiego
- Department of Microbiology, University of Massachusetts–Amherst, Amherst, MA, United States of America
| | - Roberto Orellana
- Departamento de Biología, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha, Playa Ancha, Valparaíso, Chile
| | - Joshua N. Adkins
- Biological Sciences Department, Pacific Northwest National Laboratory, Richland, Washington, DC, United States of America
| | - Carrie D. Nicora
- Biological Sciences Department, Pacific Northwest National Laboratory, Richland, Washington, DC, United States of America
| | - Young-Mo Kim
- Biological Sciences Department, Pacific Northwest National Laboratory, Richland, Washington, DC, United States of America
| | - Rosalie Chu
- Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, DC, United States of America
| | - Blake Simmons
- U.S. Department of Energy Joint Genome Institute, Berkeley, California, United States of America
| | - Kristen M. DeAngelis
- Department of Microbiology, University of Massachusetts–Amherst, Amherst, MA, United States of America
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14
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Fernandez L, Peura S, Eiler A, Linz AM, McMahon KD, Bertilsson S. Diazotroph Genomes and Their Seasonal Dynamics in a Stratified Humic Bog Lake. Front Microbiol 2020; 11:1500. [PMID: 32714313 PMCID: PMC7341956 DOI: 10.3389/fmicb.2020.01500] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 06/09/2020] [Indexed: 12/28/2022] Open
Abstract
Aquatic N-fixation is generally associated with the growth and mass development of Cyanobacteria in nitrogen-deprived photic zones. However, sequenced genomes and environmental surveys suggest active aquatic N-fixation also by many non-cyanobacterial groups. Here, we revealed the seasonal variation and genomic diversity of potential N-fixers in a humic bog lake using metagenomic data and nif gene clusters analysis. Groups with diazotrophic operons were functionally divergent and included Cholorobi, Geobacter, Desulfobacterales, Methylococcales, and Acidobacteria. In addition to nifH (a gene that encodes the dinitrogenase reductase component of the molybdenum nitrogenase), we also identified sequences corresponding to vanadium and iron-only nitrogenase genes. Within the Chlorobi population, the nitrogenase (nifH) cluster was included in a well-structured retrotransposon. Furthermore, the presence of light-harvesting photosynthesis genes implies that anoxygenic photosynthesis may fuel nitrogen fixation under the prevailing low-irradiance conditions. The presence of rnf genes (related to the expression of H+/Na+-translocating ferredoxin: NAD+ oxidoreductase) in Methylococcales and Desulfobacterales suggests that other energy-generating processes may drive the costly N-fixation in the absence of photosynthesis. The highly reducing environment of the anoxic bottom layer of Trout Bog Lake may thus also provide a suitable niche for active N-fixers and primary producers. While future studies on the activity of these potential N-fixers are needed to clarify their role in freshwater nitrogen cycling, the metagenomic data presented here enabled an initial characterization of previously overlooked diazotrophs in freshwater biomes.
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Affiliation(s)
- Leyden Fernandez
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Sari Peura
- Department of Forest Mycology and Plant Pathology, Science for Life Laboratory, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Alexander Eiler
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
- Centre for Biogeochemistry in the Anthropocene, Department of Biosciences, Section for Aquatic Biology and Toxicology, University of Oslo, Oslo, Norway
| | - Alexandra M. Linz
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin–Madison, Madison, WI, United States
| | - Katherine D. McMahon
- Department of Bacteriology, University of Wisconsin–Madison, Madison, WI, United States
- Department of Civil and Environmental Engineering, University of Wisconsin–Madison, Madison, WI, United States
| | - Stefan Bertilsson
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
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15
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Lau MP, Del Giorgio P. Reactivity, fate and functional roles of dissolved organic matter in anoxic inland waters. Biol Lett 2020; 16:20190694. [PMID: 32097596 DOI: 10.1098/rsbl.2019.0694] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The transit of organic matter (OM) through the aquatic compartment of its global cycle has been intensively studied, traditionally with a focus on the processing and degradation of its dissolved fraction (dissolved organic matter, DOM). Because this is so intimately related to oxidation, the notion tenaciously persists that where oxygen is absent, DOM turnover is markedly slowed. In this Opinion Piece, we outline how diverse processes shape, transform and degrade DOM also in anoxic aquatic environments, and we focus here on inland waters as a particular case study. A suite of biogeochemical DOM functions that have received comparatively little attention may only be expressed in anoxic conditions and may result in enhanced biogeochemical roles of these deoxygenated habitats on a network scale.
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Affiliation(s)
- Maximilian P Lau
- Département des sciences biologiques, Université du Québec à Montréal (UQAM), 141 Avenue du Président-Kennedy, Montréal, Quebec, Canada H2X 1Y4
| | - Paul Del Giorgio
- Département des sciences biologiques, Université du Québec à Montréal (UQAM), 141 Avenue du Président-Kennedy, Montréal, Quebec, Canada H2X 1Y4
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16
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Yee MO, Rotaru AE. Extracellular electron uptake in Methanosarcinales is independent of multiheme c-type cytochromes. Sci Rep 2020; 10:372. [PMID: 31941946 PMCID: PMC6962339 DOI: 10.1038/s41598-019-57206-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 12/23/2019] [Indexed: 11/14/2022] Open
Abstract
The co-occurrence of Geobacter and Methanosarcinales is often used as a proxy for the manifestation of direct interspecies electron transfer (DIET) in the environment. Here we tested eleven new co-culture combinations between methanogens and electrogens. Previously, only the most electrogenic Geobacter paired by DIET with Methanosarcinales methanogens, namely G. metallireducens and G. hydrogenophilus. Here we provide additional support, and show that five additional Methanosarcinales paired with G. metallireducens, while a strict hydrogenotroph could not. We also show that G. hydrogenophilus, which is incapable to grow with a strict hydrogenotrophic methanogen, could pair with a strict non-hydrogenotrophic Methanosarcinales. Likewise, an electrogen outside the Geobacter cluster (Rhodoferrax ferrireducens) paired with Methanosarcinales but not with strict hydrogenotrophic methanogens. The ability to interact with electrogens appears to be conserved among Methanosarcinales, the only methanogens with c-type cytochromes, including multihemes (MHC). Nonetheless, MHC, which are often linked to extracellular electron transfer, were neither unique nor universal to Methanosarcinales and only two of seven Methanosarcinales tested had MHC. Of these two, one strain had an MHC-deletion knockout available, which we hereby show is still capable to retrieve extracellular electrons from G. metallireducens or an electrode suggesting an MHC-independent strategy for extracellular electron uptake.
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Affiliation(s)
- Mon Oo Yee
- Nordcee, Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Amelia-Elena Rotaru
- Nordcee, Department of Biology, University of Southern Denmark, Odense, Denmark.
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17
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Van Steendam C, Smets I, Skerlos S, Raskin L. Improving anaerobic digestion via direct interspecies electron transfer requires development of suitable characterization methods. Curr Opin Biotechnol 2019; 57:183-190. [DOI: 10.1016/j.copbio.2019.03.018] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 03/27/2019] [Accepted: 03/27/2019] [Indexed: 02/06/2023]
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