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Pan Y, Fu YY, Zhou K, Tian T, Li YS, Yu HQ. Microbial mixotrophic denitrification using iron(II) as an assisted electron donor. WATER RESEARCH X 2023; 19:100176. [PMID: 37020531 PMCID: PMC10068250 DOI: 10.1016/j.wroa.2023.100176] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/15/2023] [Accepted: 03/16/2023] [Indexed: 06/19/2023]
Abstract
Mixotrophic denitrification processes have a great potential in nitrogen removal in biological wastewater treatment processes. However, so far, few studies have focused on the mixotrophic denitrification system using Fe(II) as an exclusively assisted electron donors and the underlying mechanisms in such a process remain unclear. Furthermore, the mechanisms by which microorganisms cover carbon, nitrogen, phosphorus and iron in an iron-assisted mixotrophic system remain unrevealed. In this work, we explore the feasibility of using Fe(II) as an assisted electron donor for enhancing simultaneous nitrogen and phosphorus removal via long-term reactor operation and batch tests. The results show that Fe(II) could provide electrons for efficient nitrate reduction and that biological reactions played a predominant role in these systems. In these systems Thermomonas, a strain of nitrate-reduction Fe(II)-oxidation bacterium, was enriched and accounted for a maximum abundance of 60.2%. These findings indicate a great potential of the Fe(II)-assisted mixotrophic denitrification system for practical use as an efficient simultaneous nitrogen and phosphorus removal process.
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Affiliation(s)
- Yuan Pan
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
- Anhui Province Key Laboratory of Industrial Wastewater and Environmental Treatment, Hefei 230026, China
| | - Ying-Ying Fu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Ke Zhou
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Tian Tian
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Yu-Sheng Li
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
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2
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Bayer T, Tomaszewski EJ, Bryce C, Kappler A, Byrne JM. Continuous cultivation of the lithoautotrophic nitrate-reducing Fe(II)-oxidizing culture KS in a chemostat bioreactor. ENVIRONMENTAL MICROBIOLOGY REPORTS 2023. [PMID: 36992623 DOI: 10.1111/1758-2229.13149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/15/2023] [Indexed: 06/19/2023]
Abstract
Laboratory-based studies on microbial Fe(II) oxidation are commonly performed for 5-10 days in small volumes with high substrate concentrations, resulting in geochemical gradients and volumetric effects caused by sampling. We used a chemostat to enable uninterrupted supply of medium and investigated autotrophic nitrate-reducing Fe(II)-oxidizing culture KS for 24 days. We analysed Fe- and N-speciation, cell-mineral associations, and the identity of minerals. Results were compared to batch systems (50 and 700 mL-static/shaken). The Fe(II) oxidation rate was highest in the chemostat with 7.57 mM Fe(II) d-1 , while the extent of oxidation was similar to the other experimental setups (average oxidation of 92% of all Fe(II)). Short-range ordered Fe(III) phases, presumably ferrihydrite, precipitated and later goethite was detected in the chemostat. The 1 mM solid phase Fe(II) remained in the chemostat, up to 15 μM of reactive nitrite was measured, and 42% of visualized cells were partially or completely mineral-encrusted, likely caused by abiotic oxidation of Fe(II) by nitrite. Despite (partial) encrustation, cells were still viable. Our results show that even with similar oxidation rates as in batch cultures, cultivating Fe(II)-oxidizing microorganisms under continuous conditions reveals the importance of reactive nitrogen intermediates on Fe(II) oxidation, mineral formation and cell-mineral interactions.
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Affiliation(s)
- Timm Bayer
- Geomicrobiology Group, Center for Applied Geoscience, University of Tuebingen, Tuebingen, Germany
| | - Elizabeth J Tomaszewski
- Geomicrobiology Group, Center for Applied Geoscience, University of Tuebingen, Tuebingen, Germany
| | - Casey Bryce
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - Andreas Kappler
- Geomicrobiology Group, Center for Applied Geoscience, University of Tuebingen, Tuebingen, Germany
- Cluster of Excellence: EXC 2124: Controlling Microbes to Fight Infection, Tuebingen, Germany
| | - James M Byrne
- School of Earth Sciences, University of Bristol, Bristol, UK
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3
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Chen G, Du Y, Fang L, Wang X, Liu C, Yu H, Feng M, Chen X, Li F. Distinct arsenic uptake feature in rice reveals the importance of N fertilization strategies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 854:158801. [PMID: 36115399 DOI: 10.1016/j.scitotenv.2022.158801] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 09/05/2022] [Accepted: 09/12/2022] [Indexed: 06/15/2023]
Abstract
The environmental behavior of arsenic (As) is commonly affected by the biogeochemical processes of iron (Fe) and nitrogen (N). In this study, field experiments were conducted to explore As uptake in rice and As translation and distribution in As-contaminated iron-rich paddy soils after applying different forms of N fertilizers, including urea (CO(NH2)2), ammonium bicarbonate (NH4HCO3), nitrate of potash (KNO3), and ammonium bicarbonate + nitrate of potash (NH4HCO3 + KNO3). The results indicated that applying nitrate N fertilizer inhibited the reduction and dissolution of As-bearing iron minerals and promoted microbial-mediated As(III) oxidation in flooded soil, thus reducing the soil As bioavailability. The concentrations of total As and inorganic As ratio (iAs/TAs) in rice grain decreased by 32.4 % and 15.4 %, respectively. However, the application of ammonium nitrogen promoted the reductive dissolution of As-bearing iron minerals and stimulated microbial As(V) reduction in flooded soil, leading to the release of As from soil to porewater. The total As concentration and inorganic As uptake ratio in rice grain increased by 20.1 % and 6.2 %, respectively, when urea was applied, and by 29.6 % and 10.5 %, respectively, when ammonium bicarbonate was applied. However, the simultaneous application of NH4+ and NO3- had no significant effect on As concentration in rice grain and its transformation in paddy soils. Ammonium nitrogen enhanced the organic As concentration in rice grain because the increased As(III) promoted As methylation in soil. In contrast, nitrate decreased the organic As uptake by rice grain because the decreased As(III) diminished As methylation in soil. The results provide reasonable N fertilization strategies for regulating the As biogeochemical process and reducing the risk of As contamination in rice.
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Affiliation(s)
- Gongning Chen
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; College of Environmental Science and Engineering, Guilin University of Technology, Guilin, 541004, China; Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin, 541004, China
| | - Yanhong Du
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Liping Fang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Xiangqin Wang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Chuanping Liu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Huanyun Yu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Mi Feng
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; College of Environmental Science and Engineering, Guilin University of Technology, Guilin, 541004, China; Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin, 541004, China
| | - Xi Chen
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Fangbai Li
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China.
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4
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Neu J, Shipps CC, Guberman-Pfeffer MJ, Shen C, Srikanth V, Spies JA, Kirchhofer ND, Yalcin SE, Brudvig GW, Batista VS, Malvankar NS. Microbial biofilms as living photoconductors due to ultrafast electron transfer in cytochrome OmcS nanowires. Nat Commun 2022; 13:5150. [PMID: 36071037 PMCID: PMC9452534 DOI: 10.1038/s41467-022-32659-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 08/09/2022] [Indexed: 11/09/2022] Open
Abstract
Light-induced microbial electron transfer has potential for efficient production of value-added chemicals, biofuels and biodegradable materials owing to diversified metabolic pathways. However, most microbes lack photoactive proteins and require synthetic photosensitizers that suffer from photocorrosion, photodegradation, cytotoxicity, and generation of photoexcited radicals that are harmful to cells, thus severely limiting the catalytic performance. Therefore, there is a pressing need for biocompatible photoconductive materials for efficient electronic interface between microbes and electrodes. Here we show that living biofilms of Geobacter sulfurreducens use nanowires of cytochrome OmcS as intrinsic photoconductors. Photoconductive atomic force microscopy shows up to 100-fold increase in photocurrent in purified individual nanowires. Photocurrents respond rapidly (<100 ms) to the excitation and persist reversibly for hours. Femtosecond transient absorption spectroscopy and quantum dynamics simulations reveal ultrafast (~200 fs) electron transfer between nanowire hemes upon photoexcitation, enhancing carrier density and mobility. Our work reveals a new class of natural photoconductors for whole-cell catalysis. Despite enormous potential of solar-driven biocatalysis, most living systems lack photoactive proteins and require toxic and expensive synthetic materials limiting the performance. Here, a class of natural photoconductors is demonstrated through sub-picosecond heme-to-heme electron transfer in bacteria-produced protein nanowires.
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Affiliation(s)
- Jens Neu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA. .,Microbial Sciences Institute, Yale University, West Haven, CT, USA.
| | - Catharine C Shipps
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Matthew J Guberman-Pfeffer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Cong Shen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Vishok Srikanth
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Jacob A Spies
- Department of Chemistry, Yale University, New Haven, CT, USA
| | | | - Sibel Ebru Yalcin
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Gary W Brudvig
- Department of Chemistry, Yale University, New Haven, CT, USA
| | | | - Nikhil S Malvankar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA. .,Microbial Sciences Institute, Yale University, West Haven, CT, USA.
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5
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Abstract
Freshwater iron mats are dynamic geochemical environments with broad ecological diversity, primarily formed by the iron-oxidizing bacteria. The community features functional groups involved in biogeochemical cycles for iron, sulfur, carbon, and nitrogen. Despite this complexity, iron mat communities provide an excellent model system for exploring microbial ecological interactions and ecological theories in situ Syntrophies and competition between the functional groups in iron mats, how they connect cycles, and the maintenance of these communities by taxons outside bacteria (the eukaryota, archaea, and viruses) have been largely unstudied. Here, we review what is currently known about freshwater iron mat communities, the taxa that reside there, and the interactions between these organisms, and we propose ways in which future studies may uncover exciting new discoveries. For example, the archaea in these mats may play a greater role than previously thought as they are diverse and widespread in iron mats based on 16S rRNA genes and include methanogenic taxa. Studies with a holistic view of the iron mat community members focusing on their diverse interactions will expand our understanding of community functions, such as those involved in pollution removal. To begin addressing questions regarding the fundamental interactions and to identify the conditions in which they occur, more laboratory culturing techniques and coculture studies, more network and keystone species analyses, and the expansion of studies to more freshwater iron mat systems are necessary. Increasingly accessible bioinformatic, geochemical, and culturing tools now open avenues to address the questions that we pose herein.
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Affiliation(s)
- Chequita N Brooks
- Department of Biology, East Carolina University, Greenville, North Carolina, USA
| | - Erin K Field
- Department of Biology, East Carolina University, Greenville, North Carolina, USA
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6
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Zhang B, Cheng HY, Wang A. Extracellular electron transfer through visible light induced excited-state outer membrane C-type cytochromes of Geobacter sulfurreducens. Bioelectrochemistry 2020; 138:107683. [PMID: 33421898 DOI: 10.1016/j.bioelechem.2020.107683] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 09/09/2020] [Accepted: 09/24/2020] [Indexed: 11/26/2022]
Abstract
Dissimilatory metal-reducing bacteria (DMRB) have a variety of c-type cytochromes (OM c-cyts) intercalated in their outer membrane, and this structure serves as the physiological basis for DMRB to carry out the extracellular electron transfer processes. Using Geobacter sulfurreducens as a model DMRB, we demonstrated that visible-light illumination could alter the electronic state of OM c-cyts from the ground state to the excited state in vivo. The existence of excited-state OM c-cyts in vivo was confirmed by spectroscopy. More importantly, excited-state OM c-cyts had a more negative potential compared to their ground-state counterparts, conferring DMRB with an extra pathway to transfer electrons to semi-conductive electron acceptors. To demonstrate this, using a TiO2-coated electrode as an electron acceptor, we showed that G. sulfurreducens could directly utilise the conduction band of TiO2 as an electron acceptor under visible-light illumination (λ > 420 nm) without causing TiO2 charge separation. When G. sulfurreducens was subject to visible-light illumination, the rate of extracellular electron transfer (EET) to TiO2 accelerated by over 8-fold compared to that observed under dark conditions. Results of additional electrochemical tests provided complementary evidence to support that G. sulfurreducens utilised excited-state OM c-cyts to enhance EET to TiO2.
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Affiliation(s)
- Bo Zhang
- CAS Key Lab of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Hao-Yi Cheng
- CAS Key Lab of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Aijie Wang
- CAS Key Lab of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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7
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Rahman MM, Roberts KL, Grace MR, Kessler AJ, Cook PLM. Role of organic carbon, nitrate and ferrous iron on the partitioning between denitrification and DNRA in constructed stormwater urban wetlands. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 666:608-617. [PMID: 30807951 DOI: 10.1016/j.scitotenv.2019.02.225] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 02/14/2019] [Accepted: 02/14/2019] [Indexed: 06/09/2023]
Abstract
Denitrification (DNF) and dissimilatory nitrate reduction to ammonium (DNRA) are two competing nitrate reduction pathways that remove or recycle nitrogen, respectively. However, factors controlling the partitioning between these two pathways are manifold and our understanding of these factors is critical for the management of N loads in constructed wetlands. An important factor that controls DNRA in an aquatic ecosystem is the electron donor, commonly organic carbon (OC) or alternatively ferrous iron and sulfide. In this study, we investigated the role of natural organic carbon (NOC) and acetate at different OC/NO3- ratios and ferrous iron on the partitioning between DNF and DNRA using the 15N-tracer method in slurries from four constructed stormwater urban wetlands in Melbourne, Australia. The carbon and nitrate experiments revealed that DNF dominated at all OC/NO3- ratios. The higher DNF and DNRA rates observed after the addition of NOC indicates that nitrate reduction was enhanced more by NOC than acetate. Moreover, addition of NOC in slurries stimulated DNRA more than DNF. Interestingly, slurries amended with Fe2+ showed that Fe2+ had significant control on the balance between DNF and DNRA. From two out of four wetlands, a significant increase in DNRA rates (p < .05) at the cost of DNF in the presence of available Fe2+ suggests DNRA is coupled to Fe2+ oxidation. Rates of DNRA increased 1.5-3.5 times in the Fe2+ treatment compared to the control. Overall, our study provides direct evidence that DNRA is linked to Fe2+ oxidation in some wetland sediments and highlights the role of Fe2+ in controlling the partitioning between removal (DNF) and recycling (DNRA) of bioavailable N in stormwater urban constructed wetlands. In our study we also measured anammox and found that it was always <0.05% of total nitrate reduction in these sediments.
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Affiliation(s)
- Md Moklesur Rahman
- Water Studies Centre, School of Chemistry, Monash University, Clayton, Australia.
| | - Keryn L Roberts
- Water Studies Centre, School of Chemistry, Monash University, Clayton, Australia.
| | - Michael R Grace
- Water Studies Centre, School of Chemistry, Monash University, Clayton, Australia.
| | - Adam J Kessler
- Water Studies Centre, School of Chemistry, Monash University, Clayton, Australia.
| | - Perran L M Cook
- Water Studies Centre, School of Chemistry, Monash University, Clayton, Australia.
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8
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Liu T, Chen D, Li X, Li F. Microbially mediated coupling of nitrate reduction and Fe(II) oxidation under anoxic conditions. FEMS Microbiol Ecol 2019; 95:5371120. [DOI: 10.1093/femsec/fiz030] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 03/06/2019] [Indexed: 11/12/2022] Open
Affiliation(s)
- Tongxu Liu
- Guangzhou Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou 510650, P. R. China
| | - Dandan Chen
- Guangzhou Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou 510650, P. R. China
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Xiaomin Li
- The Environmental Research Institute, MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, P. R. China
| | - Fangbai Li
- Guangzhou Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-environmental Science & Technology, Guangzhou 510650, P. R. China
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9
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Bryce C, Blackwell N, Schmidt C, Otte J, Huang YM, Kleindienst S, Tomaszewski E, Schad M, Warter V, Peng C, Byrne JM, Kappler A. Microbial anaerobic Fe(II) oxidation - Ecology, mechanisms and environmental implications. Environ Microbiol 2018; 20:3462-3483. [DOI: 10.1111/1462-2920.14328] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 06/15/2018] [Accepted: 06/16/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Casey Bryce
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Nia Blackwell
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | | | - Julia Otte
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Yu-Ming Huang
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | | | | | - Manuel Schad
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Viola Warter
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Chao Peng
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - James M. Byrne
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Andreas Kappler
- Geomicrobiology; University of Tübingen; Tübingen Germany
- Center for Geomicrobiology, Department of Bioscience; Aarhus University; Aarhus Denmark
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10
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Otte JM, Harter J, Laufer K, Blackwell N, Straub D, Kappler A, Kleindienst S. The distribution of active iron‐cycling bacteria in marine and freshwater sediments is decoupled from geochemical gradients. Environ Microbiol 2018; 20:2483-2499. [DOI: 10.1111/1462-2920.14260] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 04/26/2018] [Accepted: 04/26/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Julia M. Otte
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen Germany
| | - Johannes Harter
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen Germany
| | - Katja Laufer
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen Germany
- Center for Geomicrobiology, Department of BioscienceAarhus University Denmark
| | - Nia Blackwell
- Microbial Ecology, Center for Applied GeosciencesUniversity of Tübingen Germany
| | - Daniel Straub
- Microbial Ecology, Center for Applied GeosciencesUniversity of Tübingen Germany
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen Germany
- Center for Geomicrobiology, Department of BioscienceAarhus University Denmark
| | - Sara Kleindienst
- Microbial Ecology, Center for Applied GeosciencesUniversity of Tübingen Germany
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11
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Peng C, Sundman A, Bryce C, Catrouillet C, Borch T, Kappler A. Oxidation of Fe(II)-Organic Matter Complexes in the Presence of the Mixotrophic Nitrate-Reducing Fe(II)-Oxidizing Bacterium Acidovorax sp. BoFeN1. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:5753-5763. [PMID: 29671587 DOI: 10.1021/acs.est.8b00953] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Fe(II)-organic matter (Fe(II)-OM) complexes are abundant in the environment and may play a key role for the behavior of Fe and pollutants. Mixotrophic nitrate-reducing Fe(II)-oxidizing bacteria (NRFeOx) reduce nitrate coupled to the oxidation of organic compounds and Fe(II). Fe(II) oxidation may occur enzymatically or abiotically by reaction with nitrite that forms during heterotrophic denitrification. However, it is unknown whether Fe(II)-OM complexes can be oxidized by NRFeOx. We used cell-suspension experiments with the mixotrophic nitrate-reducing Fe(II)-oxidizing bacterium Acidovorax sp. strain BoFeN1 to reveal the role of nonorganically bound Fe(II) (aqueous Fe(II)) and nitrite for the rates and extent of oxidation of Fe(II)-OM complexes (Fe(II)-citrate, Fe(II)-EDTA, Fe(II)-humic acid, and Fe(II)-fulvic acid). We found that Fe(II)-OM complexation inhibited microbial nitrate-reducing Fe(II) oxidation; large colloidal and negatively charged complexes showed lower oxidation rates than aqueous Fe(II). Accumulation of nitrite and fast abiotic oxidation of Fe(II)-OM complexes only happened in the presence of aqueous Fe(II) that probably interacted with (nitrite-reducing) enzymes in the periplasm causing nitrite accumulation in the periplasm and outside of the cells, whereas Fe(II)-OM complexes probably could not enter the periplasm and cause nitrite accumulation. These results suggest that Fe(II) oxidation by mixotrophic nitrate reducers in the environment depends on Fe(II) speciation, and that aqueous Fe(II) potentially plays a critical role in regulating microbial denitrification processes.
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Affiliation(s)
- Chao Peng
- Geomicrobiology, Center for Applied Geoscience , University of Tuebingen , Sigwartstrasse 10 , 72076 Tuebingen , Germany
| | - Anneli Sundman
- Geomicrobiology, Center for Applied Geoscience , University of Tuebingen , Sigwartstrasse 10 , 72076 Tuebingen , Germany
| | - Casey Bryce
- Geomicrobiology, Center for Applied Geoscience , University of Tuebingen , Sigwartstrasse 10 , 72076 Tuebingen , Germany
| | | | - Thomas Borch
- Department of Soil and Crop Sciences , Colorado State University , Fort Collins , Colorado 80523 , United States
- Department of Chemistry , Colorado State University , Fort Collins , Colorado 80523 , United States
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geoscience , University of Tuebingen , Sigwartstrasse 10 , 72076 Tuebingen , Germany
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12
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Insights into Carbon Metabolism Provided by Fluorescence In Situ Hybridization-Secondary Ion Mass Spectrometry Imaging of an Autotrophic, Nitrate-Reducing, Fe(II)-Oxidizing Enrichment Culture. Appl Environ Microbiol 2018; 84:AEM.02166-17. [PMID: 29500258 DOI: 10.1128/aem.02166-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 02/20/2018] [Indexed: 01/03/2023] Open
Abstract
The enrichment culture KS is one of the few existing autotrophic, nitrate-reducing, Fe(II)-oxidizing cultures that can be continuously transferred without an organic carbon source. We used a combination of catalyzed amplification reporter deposition fluorescence in situ hybridization (CARD-FISH) and nanoscale secondary ion mass spectrometry (NanoSIMS) to analyze community dynamics, single-cell activities, and interactions among the two most abundant microbial community members (i.e., Gallionellaceae sp. and Bradyrhizobium spp.) under autotrophic and heterotrophic growth conditions. CARD-FISH cell counts showed the dominance of the Fe(II) oxidizer Gallionellaceae sp. under autotrophic conditions as well as of Bradyrhizobium spp. under heterotrophic conditions. We used NanoSIMS to monitor the fate of 13C-labeled bicarbonate and acetate as well as 15N-labeled ammonium at the single-cell level for both taxa. Under autotrophic conditions, only the Gallionellaceae sp. was actively incorporating 13C-labeled bicarbonate and 15N-labeled ammonium. Interestingly, both Bradyrhizobium spp. and Gallionellaceae sp. became enriched in [13C]acetate and [15N]ammonium under heterotrophic conditions. Our experiments demonstrated that Gallionellaceae sp. was capable of assimilating [13C]acetate while Bradyrhizobium spp. were not able to fix CO2, although a metagenomics survey of culture KS recently revealed that Gallionellaceae sp. lacks genes for acetate uptake and that the Bradyrhizobium sp. carries the genetic potential to fix CO2 The study furthermore extends our understanding of the microbial reactions that interlink the nitrogen and Fe cycles in the environment.IMPORTANCE Microbial mechanisms by which Fe(II) is oxidized with nitrate as the terminal electron acceptor are generally referred to as "nitrate-dependent Fe(II) oxidation" (NDFO). NDFO has been demonstrated in laboratory cultures (such as the one studied in this work) and in a variety of marine and freshwater sediments. Recently, the importance of NDFO for the transport of sediment-derived Fe in aquatic ecosystems has been emphasized in a series of studies discussing the impact of NDFO for sedimentary nutrient cycling and redox dynamics in marine and freshwater environments. In this article, we report results from an isotope labeling study performed with the autotrophic, nitrate-reducing, Fe(II)-oxidizing enrichment culture KS, which was first described by Straub et al. (1) about 20 years ago. Our current study builds on the recently published metagenome of culture KS (2).
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Camacho A, Walter XA, Picazo A, Zopfi J. Photoferrotrophy: Remains of an Ancient Photosynthesis in Modern Environments. Front Microbiol 2017; 8:323. [PMID: 28377745 PMCID: PMC5359306 DOI: 10.3389/fmicb.2017.00323] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 02/15/2017] [Indexed: 11/13/2022] Open
Abstract
Photoferrotrophy, the process by which inorganic carbon is fixed into organic matter using light as an energy source and reduced iron [Fe(II)] as an electron donor, has been proposed as one of the oldest photoautotrophic metabolisms on Earth. Under the iron-rich (ferruginous) but sulfide poor conditions dominating the Archean ocean, this type of metabolism could have accounted for most of the primary production in the photic zone. Here we review the current knowledge of biogeochemical, microbial and phylogenetic aspects of photoferrotrophy, and evaluate the ecological significance of this process in ancient and modern environments. From the ferruginous conditions that prevailed during most of the Archean, the ancient ocean evolved toward euxinic (anoxic and sulfide rich) conditions and, finally, much after the advent of oxygenic photosynthesis, to a predominantly oxic environment. Under these new conditions photoferrotrophs lost importance as primary producers, and now photoferrotrophy remains as a vestige of a formerly relevant photosynthetic process. Apart from the geological record and other biogeochemical markers, modern environments resembling the redox conditions of these ancient oceans can offer insights into the past significance of photoferrotrophy and help to explain how this metabolism operated as an important source of organic carbon for the early biosphere. Iron-rich meromictic (permanently stratified) lakes can be considered as modern analogs of the ancient Archean ocean, as they present anoxic ferruginous water columns where light can still be available at the chemocline, thus offering suitable niches for photoferrotrophs. A few bacterial strains of purple bacteria as well as of green sulfur bacteria have been shown to possess photoferrotrophic capacities, and hence, could thrive in these modern Archean ocean analogs. Studies addressing the occurrence and the biogeochemical significance of photoferrotrophy in ferruginous environments have been conducted so far in lakes Matano, Pavin, La Cruz, and the Kabuno Bay of Lake Kivu. To date, only in the latter two lakes a biogeochemical role of photoferrotrophs has been confirmed. In this review we critically summarize the current knowledge on iron-driven photosynthesis, as a remains of ancient Earth biogeochemistry.
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Affiliation(s)
- Antonio Camacho
- Cavanilles Institute for Biodiversity and Evolutionary Biology, University of ValenciaBurjassot, Spain
| | - Xavier A. Walter
- Bristol BioEnergy Centre, Bristol Robotics Laboratory, University of the West of EnglandBristol, UK
| | - Antonio Picazo
- Cavanilles Institute for Biodiversity and Evolutionary Biology, University of ValenciaBurjassot, Spain
| | - Jakob Zopfi
- Aquatic and Stable Isotope Biogeochemistry, Department of Environmental Sciences, University of BaselBasel, Switzerland
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Kappler A, Bryce C. Cryptic biogeochemical cycles: unravelling hidden redox reactions. Environ Microbiol 2017; 19:842-846. [DOI: 10.1111/1462-2920.13687] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andreas Kappler
- Geomicrobiology; Center for Applied Geosciences, University of Tuebingen; Germany
| | - Casey Bryce
- Geomicrobiology; Center for Applied Geosciences, University of Tuebingen; Germany
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Berg JS, Michellod D, Pjevac P, Martinez-Perez C, Buckner CRT, Hach PF, Schubert CJ, Milucka J, Kuypers MMM. Intensive cryptic microbial iron cycling in the low iron water column of the meromictic Lake Cadagno. Environ Microbiol 2016; 18:5288-5302. [DOI: 10.1111/1462-2920.13587] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 10/18/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Jasmine S. Berg
- Max Planck Institute for Marine Microbiology; Bremen 28359 Germany
| | - Dolma Michellod
- Max Planck Institute for Marine Microbiology; Bremen 28359 Germany
| | - Petra Pjevac
- Max Planck Institute for Marine Microbiology; Bremen 28359 Germany
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science; University of Vienna; Vienna Austria
| | | | | | - Philipp F. Hach
- Max Planck Institute for Marine Microbiology; Bremen 28359 Germany
| | - Carsten J. Schubert
- Eawag, Swiss Federal Institute of Aquatic Science and Technology; Kastanienbaum Switzerland
| | - Jana Milucka
- Max Planck Institute for Marine Microbiology; Bremen 28359 Germany
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Evidence for the Existence of Autotrophic Nitrate-Reducing Fe(II)-Oxidizing Bacteria in Marine Coastal Sediment. Appl Environ Microbiol 2016; 82:6120-6131. [PMID: 27496777 PMCID: PMC5068159 DOI: 10.1128/aem.01570-16] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 08/02/2016] [Indexed: 11/23/2022] Open
Abstract
Nitrate-reducing Fe(II)-oxidizing microorganisms were described for the first time ca. 20 years ago. Most pure cultures of nitrate-reducing Fe(II) oxidizers can oxidize Fe(II) only under mixotrophic conditions, i.e., when an organic cosubstrate is provided. A small number of nitrate-reducing Fe(II)-oxidizing cultures have been proposed to grow autotrophically, but unambiguous evidence for autotrophy has not always been provided. Thus, it is still unclear whether or to what extent Fe(II) oxidation coupled to nitrate reduction is an enzymatically catalyzed and energy-yielding autotrophic process or whether Fe(II) is abiotically oxidized by nitrite from heterotrophic nitrate reduction. The aim of the present study was to find evidence for the existence of autotrophic nitrate-reducing Fe(II) oxidizers in coastal marine sediments. Microcosm incubations showed that with increasing incubation times, the stoichiometric ratio of reduced nitrate/oxidized Fe(II) [NO3−reduced/Fe(II)oxidized] decreased, indicating a decreasing contribution of heterotrophic denitrification and/or an increasing contribution of autotrophic nitrate-reducing Fe(II) oxidation over time. After incubations of sediment slurries for >10 weeks, nitrate-reducing activity ceased, although nitrate was still present. This suggests that heterotrophic nitrate reduction had ceased due to the depletion of readily available organic carbon. However, after the addition of Fe(II) to these batch incubation mixtures, the nitrate-reducing activity resumed, and Fe(II) was oxidized, indicating the activity of autotrophic nitrate-reducing Fe(II) oxidizers. The concurrent reduction of 14C-labeled bicarbonate concentrations unambiguously proved that autotrophic C fixation occurred during Fe(II) oxidation and nitrate reduction. Our results clearly demonstrated that autotrophic nitrate-reducing Fe(II)-oxidizing bacteria were present in the investigated coastal marine sediments.
IMPORTANCE Twenty years after the discovery of nitrate-reducing Fe(II) oxidizers, it is still controversially discussed whether autotrophic nitrate-reducing Fe(II)-oxidizing microorganisms exist and to what extent Fe(II) oxidation in this reduction/oxidation process is enzymatically catalyzed or which role abiotic side reactions of Fe(II) with reactive N species play. Most pure cultures of nitrate-reducing Fe(II) oxidizers are mixotrophic; i.e., they need an organic cosubstrate to maintain their activity over several cultural transfers. For the few existing autotrophic isolates and enrichment cultures, either the mechanism of nitrate-reducing Fe(II) oxidation is not known or evidence for their autotrophic lifestyle is controversial. In the present study, we provide evidence for the existence of autotrophic nitrate-reducing Fe(II) oxidizers in coastal marine sediments. The evidence is based on stoichiometries of nitrate reduction and Fe(II) oxidation determined in microcosm incubations and the incorporation of carbon from CO2 under conditions that favor the activity of nitrate-reducing Fe(II) oxidizers.
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Chan CS, Emerson D, Luther GW. The role of microaerophilic Fe-oxidizing micro-organisms in producing banded iron formations. GEOBIOLOGY 2016; 14:509-528. [PMID: 27392195 DOI: 10.1111/gbi.12192] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 04/25/2016] [Indexed: 06/06/2023]
Abstract
Despite the historical and economic significance of banded iron formations (BIFs), we have yet to resolve the formation mechanisms. On modern Earth, neutrophilic microaerophilic Fe-oxidizing micro-organisms (FeOM) produce copious amounts of Fe oxyhydroxides, leading us to wonder whether similar organisms played a role in producing BIFs. To evaluate this, we review the current knowledge of modern microaerophilic FeOM in the context of BIF paleoenvironmental studies. In modern environments wherever Fe(II) and O2 co-exist, microaerophilic FeOM proliferate. These organisms grow in a variety of environments, including the marine water column redoxcline, which is where BIF precursor minerals likely formed. FeOM can grow across a range of O2 concentrations, measured as low as 2 μm to date, although lower concentrations have not been tested. While some extant FeOM can tolerate high O2 concentrations, many FeOM appear to prefer and thrive at low O2 concentrations (~3-25 μm). These are similar to the estimated dissolved O2 concentrations in the few hundred million years prior to the 'Great Oxidation Event' (GOE). We compare biotic and abiotic Fe oxidation kinetics in the presence of varying levels of O2 and show that microaerophilic FeOM contribute substantially to Fe oxidation, at rates fast enough to account for BIF deposition. Based on this synthesis, we propose that microaerophilic FeOM were capable of playing a significant role in depositing the largest, most well-known BIFs associated with the GOE, as well as afterward when global O2 levels increased.
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Affiliation(s)
- C S Chan
- Department of Geological Sciences, University of Delaware, and the Delaware Biotechnology Institute, Newark, DE, USA
- School of Marine Science and Policy, University of Delaware, Newark & Lewes, DE, USA
| | - D Emerson
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, USA
| | - G W Luther
- School of Marine Science and Policy, University of Delaware, Newark & Lewes, DE, USA
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Laufer K, Byrne JM, Glombitza C, Schmidt C, Jørgensen BB, Kappler A. Anaerobic microbial Fe(II) oxidation and Fe(III) reduction in coastal marine sediments controlled by organic carbon content. Environ Microbiol 2016; 18:3159-74. [DOI: 10.1111/1462-2920.13387] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 05/18/2016] [Accepted: 05/20/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Katja Laufer
- Geomicrobiology, Center for Applied Geosciences; University of Tuebingen; Tuebingen Germany
| | - James M. Byrne
- Geomicrobiology, Center for Applied Geosciences; University of Tuebingen; Tuebingen Germany
| | - Clemens Glombitza
- Department of Bioscience; Center for Geomicrobiology, Aarhus University; Aarhus Denmark
| | - Caroline Schmidt
- Geomicrobiology, Center for Applied Geosciences; University of Tuebingen; Tuebingen Germany
| | - Bo Barker Jørgensen
- Department of Bioscience; Center for Geomicrobiology, Aarhus University; Aarhus Denmark
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences; University of Tuebingen; Tuebingen Germany
- Department of Bioscience; Center for Geomicrobiology, Aarhus University; Aarhus Denmark
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Mineralogical Diversity in Lake Pavin: Connections with Water Column Chemistry and Biomineralization Processes. MINERALS 2016. [DOI: 10.3390/min6020024] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Schmid G, Zeitvogel F, Hao L, Ingino P, Adaktylou I, Eickhoff M, Obst M. Submicron-Scale Heterogeneities in Nickel Sorption of Various Cell-Mineral Aggregates Formed by Fe(II)-Oxidizing Bacteria. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:114-125. [PMID: 26588096 DOI: 10.1021/acs.est.5b02955] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Fe(II)-oxidizing bacteria form biogenic cell-mineral aggregates (CMAs) composed of microbial cells, extracellular organic compounds, and ferric iron minerals. CMAs are capable of immobilizing large quantities of heavy metals, such as nickel, via sorption processes. CMAs play an important role for the fate of heavy metals in the environment, particularly in systems characterized by elevated concentrations of dissolved metals, such as mine drainage or contaminated sediments. We applied scanning transmission (soft) X-ray microscopy (STXM) spectrotomography for detailed 3D chemical mapping of nickel sorbed to CMAs on the submicron scale. We analyzed different CMAs produced by phototrophic or nitrate-reducing microbial Fe(II) oxidation and, in addition, a twisted stalk structure obtained from an environmental biofilm. Nickel showed a heterogeneous distribution and was found to be preferentially sorbed to biogenically precipitated iron minerals such as Fe(III)-(oxyhydr)oxides and, to a minor extent, associated with organic compounds. Some distinct nickel accumulations were identified on the surfaces of CMAs. Additional information obtained from scatter plots and angular distance maps, showing variations in the nickel-iron and nickel-organic carbon ratios, also revealed a general correlation between nickel and iron. Although a high correlation between nickel and iron was observed in 2D maps, 3D maps revealed this to be partly due to projection artifacts. In summary, by combining different approaches for data analysis, we unambiguously showed the heterogeneous sorption behavior of nickel to CMAs.
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Affiliation(s)
- Gregor Schmid
- Environmental Analytical Microscopy, Center for Applied Geoscience, University of Tübingen , Hölderlinstrasse 12, 72074 Tübingen, Germany
| | - Fabian Zeitvogel
- Environmental Analytical Microscopy, Center for Applied Geoscience, University of Tübingen , Hölderlinstrasse 12, 72074 Tübingen, Germany
| | - Likai Hao
- Environmental Analytical Microscopy, Center for Applied Geoscience, University of Tübingen , Hölderlinstrasse 12, 72074 Tübingen, Germany
| | - Pablo Ingino
- Environmental Analytical Microscopy, Center for Applied Geoscience, University of Tübingen , Hölderlinstrasse 12, 72074 Tübingen, Germany
| | - Irini Adaktylou
- Environmental Analytical Microscopy, Center for Applied Geoscience, University of Tübingen , Hölderlinstrasse 12, 72074 Tübingen, Germany
| | - Merle Eickhoff
- Environmental Analytical Microscopy, Center for Applied Geoscience, University of Tübingen , Hölderlinstrasse 12, 72074 Tübingen, Germany
| | - Martin Obst
- Environmental Analytical Microscopy, Center for Applied Geoscience, University of Tübingen , Hölderlinstrasse 12, 72074 Tübingen, Germany
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Tian C, Wang C, Tian Y, Wu X, Xiao B. Vertical distribution of Fe and Fe(III)-reducing bacteria in the sediments of Lake Donghu, China. Can J Microbiol 2015; 61:575-83. [PMID: 26156094 DOI: 10.1139/cjm-2015-0129] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In lake sediments, iron (Fe) is the most versatile element, and the redox cycling of Fe has a wide influence on the biogeochemical cycling of organic and inorganic substances. The aim of the present study was to analyze the vertical distribution of Fe and Fe(III)-reducing bacteria (FeRB) in the surface sediment (30 cm) of Lake Donghu, China. At the 3 sites we surveyed, FeRB and Fe(II)-oxidizing bacteria (FeOB) coexisted in anoxic sediments. Geobacter-related FeRB accounted for 5%-31% of the total Bacteria, while Gallionella-related FeOB accounted for only 0.1%-1.3%. A significant correlation between the relative abundance of poorly crystalline Fe and Geobacter spp. suggested that poorly crystalline Fe favored microbial Fe(III) reduction. Poorly crystalline Fe and Geobacter spp. were significantly associated with solid-phase Fe(II) and total inorganic phosphorus levels. Pore water Fe(II) concentrations negatively correlated with NO3(-) at all sites. We concluded that Geobacter spp. were abundant in the sediments of Lake Donghu, and the redox of Fe might participate in the cycling of nitrogen and phosphorus in sediments. These observations provided insight into the roles of microbial Fe cycling in lake sediments.
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Affiliation(s)
- Cuicui Tian
- a Key Laboratory of Algal Biology of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, People's Republic of China.,b University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Chunbo Wang
- a Key Laboratory of Algal Biology of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, People's Republic of China.,b University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yingying Tian
- a Key Laboratory of Algal Biology of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, People's Republic of China.,b University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Xingqiang Wu
- a Key Laboratory of Algal Biology of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, People's Republic of China
| | - Bangding Xiao
- a Key Laboratory of Algal Biology of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, People's Republic of China
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Byrne JM, Klueglein N, Pearce C, Rosso KM, Appel E, Kappler A. Redox cycling of Fe(II) and Fe(III) in magnetite by Fe-metabolizing bacteria. Science 2015; 347:1473-6. [PMID: 25814583 DOI: 10.1126/science.aaa4834] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Microorganisms are a primary control on the redox-induced cycling of iron in the environment. Despite the ability of bacteria to grow using both Fe(II) and Fe(III) bound in solid-phase iron minerals, it is currently unknown whether changing environmental conditions enable the sharing of electrons in mixed-valent iron oxides between bacteria with different metabolisms. We show through magnetic and spectroscopic measurements that the phototrophic Fe(II)-oxidizing bacterium Rhodopseudomonas palustris TIE-1 oxidizes magnetite (Fe3O4) nanoparticles using light energy. This process is reversible in co-cultures by the anaerobic Fe(III)-reducing bacterium Geobacter sulfurreducens. These results demonstrate that Fe ions bound in the highly crystalline mineral magnetite are bioavailable as electron sinks and electron sources under varying environmental conditions, effectively rendering magnetite a naturally occurring battery.
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Affiliation(s)
- James M Byrne
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen, Germany.
| | - Nicole Klueglein
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen, Germany
| | - Carolyn Pearce
- School of Chemistry, University of Manchester, M13 9PL Manchester, UK. Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Kevin M Rosso
- Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Erwin Appel
- Geophysics, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen, Germany
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen, Germany
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Melton ED, Swanner ED, Behrens S, Schmidt C, Kappler A. The interplay of microbially mediated and abiotic reactions in the biogeochemical Fe cycle. Nat Rev Microbiol 2014; 12:797-808. [DOI: 10.1038/nrmicro3347] [Citation(s) in RCA: 503] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Melton ED, Stief P, Behrens S, Kappler A, Schmidt C. High spatial resolution of distribution and interconnections between Fe- and N-redox processes in profundal lake sediments. Environ Microbiol 2014; 16:3287-303. [DOI: 10.1111/1462-2920.12566] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 07/05/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Emily D. Melton
- Geomicrobiology; Center for Applied Geosciences; University of Tübingen; Tübingen 72076 Germany
| | - Peter Stief
- Microsensor Research Group; Max Planck Institute for Marine Microbiology; Bremen Germany
| | - Sebastian Behrens
- Geomicrobiology; Center for Applied Geosciences; University of Tübingen; Tübingen 72076 Germany
| | - Andreas Kappler
- Geomicrobiology; Center for Applied Geosciences; University of Tübingen; Tübingen 72076 Germany
| | - Caroline Schmidt
- Geomicrobiology; Center for Applied Geosciences; University of Tübingen; Tübingen 72076 Germany
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Electron uptake by iron-oxidizing phototrophic bacteria. Nat Commun 2014; 5:3391. [PMID: 24569675 DOI: 10.1038/ncomms4391] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 02/05/2014] [Indexed: 11/08/2022] Open
Abstract
Oxidation-reduction reactions underlie energy generation in nearly all life forms. Although most organisms use soluble oxidants and reductants, some microbes can access solid-phase materials as electron-acceptors or -donors via extracellular electron transfer. Many studies have focused on the reduction of solid-phase oxidants. Far less is known about electron uptake via microbial extracellular electron transfer, and almost nothing is known about the associated mechanisms. Here we show that the iron-oxidizing photoautotroph Rhodopseudomonas palustris TIE-1 accepts electrons from a poised electrode, with carbon dioxide as the sole carbon source/electron acceptor. Both electron uptake and ruBisCo form I expression are stimulated by light. Electron uptake also occurs in the dark, uncoupled from photosynthesis. Notably, the pioABC operon, which encodes a protein system essential for photoautotrophic growth by ferrous iron oxidation, influences electron uptake. These data reveal a previously unknown metabolic versatility of photoferrotrophs to use extracellular electron transfer for electron uptake.
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Interference of ferric ions with ferrous iron quantification using the ferrozine assay. J Microbiol Methods 2013; 95:366-7. [DOI: 10.1016/j.mimet.2013.10.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 10/08/2013] [Indexed: 11/23/2022]
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Potential role of nitrite for abiotic Fe(II) oxidation and cell encrustation during nitrate reduction by denitrifying bacteria. Appl Environ Microbiol 2013; 80:1051-61. [PMID: 24271182 DOI: 10.1128/aem.03277-13] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microorganisms have been observed to oxidize Fe(II) at neutral pH under anoxic and microoxic conditions. While most of the mixotrophic nitrate-reducing Fe(II)-oxidizing bacteria become encrusted with Fe(III)-rich minerals, photoautotrophic and microaerophilic Fe(II) oxidizers avoid cell encrustation. The Fe(II) oxidation mechanisms and the reasons for encrustation remain largely unresolved. Here we used cultivation-based methods and electron microscopy to compare two previously described nitrate-reducing Fe(II) oxidizers ( Acidovorax sp. strain BoFeN1 and Pseudogulbenkiania sp. strain 2002) and two heterotrophic nitrate reducers (Paracoccus denitrificans ATCC 19367 and P. denitrificans Pd 1222). All four strains oxidized ∼8 mM Fe(II) within 5 days in the presence of 5 mM acetate and accumulated nitrite (maximum concentrations of 0.8 to 1.0 mM) in the culture media. Iron(III) minerals, mainly goethite, formed and precipitated extracellularly in close proximity to the cell surface. Interestingly, mineral formation was also observed within the periplasm and cytoplasm; intracellular mineralization is expected to be physiologically disadvantageous, yet acetate consumption continued to be observed even at an advanced stage of Fe(II) oxidation. Extracellular polymeric substances (EPS) were detected by lectin staining with fluorescence microscopy, particularly in the presence of Fe(II), suggesting that EPS production is a response to Fe(II) toxicity or a strategy to decrease encrustation. Based on the data presented here, we propose a nitrite-driven, indirect mechanism of cell encrustation whereby nitrite forms during heterotrophic denitrification and abiotically oxidizes Fe(II). This work adds to the known assemblage of Fe(II)-oxidizing bacteria in nature and complicates our ability to delineate microbial Fe(II) oxidation in ancient microbes preserved as fossils in the geological record.
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Kanaparthi D, Pommerenke B, Casper P, Dumont MG. Chemolithotrophic nitrate-dependent Fe(II)-oxidizing nature of actinobacterial subdivision lineage TM3. THE ISME JOURNAL 2013; 7:1582-94. [PMID: 23514778 PMCID: PMC3721109 DOI: 10.1038/ismej.2013.38] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 01/31/2013] [Accepted: 02/03/2013] [Indexed: 11/08/2022]
Abstract
Anaerobic nitrate-dependent Fe(II) oxidation is widespread in various environments and is known to be performed by both heterotrophic and autotrophic microorganisms. Although Fe(II) oxidation is predominantly biological under acidic conditions, to date most of the studies on nitrate-dependent Fe(II) oxidation were from environments of circumneutral pH. The present study was conducted in Lake Grosse Fuchskuhle, a moderately acidic ecosystem receiving humic acids from an adjacent bog, with the objective of identifying, characterizing and enumerating the microorganisms responsible for this process. The incubations of sediment under chemolithotrophic nitrate-dependent Fe(II)-oxidizing conditions have shown the enrichment of TM3 group of uncultured Actinobacteria. A time-course experiment done on these Actinobacteria showed a consumption of Fe(II) and nitrate in accordance with the expected stoichiometry (1:0.2) required for nitrate-dependent Fe(II) oxidation. Quantifications done by most probable number showed the presence of 1 × 10(4) autotrophic and 1 × 10(7) heterotrophic nitrate-dependent Fe(II) oxidizers per gram fresh weight of sediment. The analysis of microbial community by 16S rRNA gene amplicon pyrosequencing showed that these actinobacterial sequences correspond to ~0.6% of bacterial 16S rRNA gene sequences. Stable isotope probing using (13)CO2 was performed with the lake sediment and showed labeling of these Actinobacteria. This indicated that they might be important autotrophs in this environment. Although these Actinobacteria are not dominant members of the sediment microbial community, they could be of functional significance due to their contribution to the regeneration of Fe(III), which has a critical role as an electron acceptor for anaerobic microorganisms mineralizing sediment organic matter. To the best of our knowledge this is the first study to show the autotrophic nitrate-dependent Fe(II)-oxidizing nature of TM3 group of uncultured Actinobacteria.
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Affiliation(s)
- Dheeraj Kanaparthi
- Department of Biogeochemistry, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Bianca Pommerenke
- Department of Biogeochemistry, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Peter Casper
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department of Limnology of Stratified Lakes, Stechlin, Germany
| | - Marc G Dumont
- Department of Biogeochemistry, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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Nitrate-dependent ferrous iron oxidation by anaerobic ammonium oxidation (anammox) bacteria. Appl Environ Microbiol 2013; 79:4087-93. [PMID: 23624480 DOI: 10.1128/aem.00743-13] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We examined nitrate-dependent Fe(2+) oxidation mediated by anaerobic ammonium oxidation (anammox) bacteria. Enrichment cultures of "Candidatus Brocadia sinica" anaerobically oxidized Fe(2+) and reduced NO3(-) to nitrogen gas at rates of 3.7 ± 0.2 and 1.3 ± 0.1 (mean ± standard deviation [SD]) nmol mg protein(-1) min(-1), respectively (37°C and pH 7.3). This nitrate reduction rate is an order of magnitude lower than the anammox activity of "Ca. Brocadia sinica" (10 to 75 nmol NH4(+) mg protein(-1) min(-1)). A (15)N tracer experiment demonstrated that coupling of nitrate-dependent Fe(2+) oxidation and the anammox reaction was responsible for producing nitrogen gas from NO3(-) by "Ca. Brocadia sinica." The activities of nitrate-dependent Fe(2+) oxidation were dependent on temperature and pH, and the highest activities were seen at temperatures of 30 to 45°C and pHs ranging from 5.9 to 9.8. The mean half-saturation constant for NO3(-) ± SD of "Ca. Brocadia sinica" was determined to be 51 ± 21 μM. Nitrate-dependent Fe(2+) oxidation was further demonstrated by another anammox bacterium, "Candidatus Scalindua sp.," whose rates of Fe(2+) oxidation and NO3(-) reduction were 4.7 ± 0.59 and 1.45 ± 0.05 nmol mg protein(-1) min(-1), respectively (20°C and pH 7.3). Co-occurrence of nitrate-dependent Fe(2+) oxidation and the anammox reaction decreased the molar ratios of consumed NO2(-) to consumed NH4(+) (ΔNO2(-)/ΔNH4(+)) and produced NO3(-) to consumed NH4(+) (ΔNO3(-)/ΔNH4(+)). These reactions are preferable to the application of anammox processes for wastewater treatment.
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30
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Emerson D, Roden E, Twining BS. The microbial ferrous wheel: iron cycling in terrestrial, freshwater, and marine environments. Front Microbiol 2012; 3:383. [PMID: 23118735 PMCID: PMC3484406 DOI: 10.3389/fmicb.2012.00383] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 10/14/2012] [Indexed: 11/24/2022] Open
Affiliation(s)
- David Emerson
- Bigelow Laboratory for Ocean Sciences East Boothbay, ME, USA
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