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Reyes-Umana V, Ewens SD, Meier DAO, Coates JD. Integration of molecular and computational approaches paints a holistic portrait of obscure metabolisms. mBio 2023; 14:e0043123. [PMID: 37855625 PMCID: PMC10746228 DOI: 10.1128/mbio.00431-23] [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] [Indexed: 10/20/2023] Open
Abstract
Microorganisms are essential drivers of earth's geochemical cycles. However, the significance of elemental redox cycling mediated by microorganisms is often underestimated beyond the most well-studied nutrient cycles. Phosphite, (per)chlorate, and iodate are each considered esoteric substrates metabolized by microorganisms. However, recent investigations have indicated that these metabolisms are widespread and ubiquitous, affirming a need to continue studying the underlying microbiology to understand their biogeochemical effects and their interface with each other and our biosphere. This review focuses on combining canonical techniques of culturing microorganisms with modern omic approaches to further our understanding of obscure metabolic pathways and elucidate their importance in global biogeochemical cycles. Using these approaches, marker genes of interest have already been identified for phosphite, (per)chlorate, and iodate using traditional microbial physiology and genetics. Subsequently, their presence was queried to reveal the distribution of metabolic pathways in the environment using publicly available databases. In conjunction with each other, computational and experimental techniques provide a more comprehensive understanding of the location of these microorganisms, their underlying biochemistry and genetics, and how they tie into our planet's geochemical cycles.
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Affiliation(s)
- Victor Reyes-Umana
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - Sophia D. Ewens
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - David A. O. Meier
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - John D. Coates
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
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Liu Q, Niu X, Zhang D, Ye X, Tan P, Shu T, Lin Z. Phototransformation of phosphite induced by zinc oxide nanoparticles (ZnO NPs) in aquatic environments. WATER RESEARCH 2023; 245:120571. [PMID: 37683523 DOI: 10.1016/j.watres.2023.120571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/16/2023] [Accepted: 09/01/2023] [Indexed: 09/10/2023]
Abstract
Phosphite, an essential component in the biogeochemical phosphorus cycle, may make significant contributions to the bioavailable phosphorus pool as well as water eutrophication. However, to date, the potential impacts of coexisting photochemically active substances on the environmental fate and transformation of phosphite in aquatic environments have been sparsely elucidated. In the present study, the effect of zinc oxide nanoparticles (ZnO NPs), a widely distributed photocatalyst in aquatic environments, on phosphite phototransformation under simulated solar irradiation was systematically investigated. The physicochemical characteristics of the pristine and reacted ZnO NPs were thoroughly characterized. The results showed that the presence of ZnO NPs induced the indirect phototransformation of phosphite to phosphate, and the reaction rate increased with increasing ZnO NPs concentration. Through experiments with quenching and trapping free radicals, it was proved that photogenerated reactive oxygen species (ROS), such as hydroxyl radical (•OH), superoxide anion (O2•-), and singlet oxygen (1O2), made substantial contributions to phosphite phototransformation. In addition, the influencing factors such as initial phosphite concentration, pH, water matrixes (Cl-, F-, Br-, SO42-, NO3-, NO2-, HCO3-, humic acid (HA) and citric acid (CA)) were investigated. The component of generated precipitates after the phosphite phototransformation induced by ZnO NPs was still dominated by ZnO NPs, while the presence of amorphous Zn3(PO4)2 was identified. This work explored ZnO NPs-mediated phosphite phototransformation processes, indicating that nanophotocatalysts released into aquatic environments such as ZnO NPs may function as photosensitizers to play a beneficial role in the transformation of phosphite to phosphate, thereby potentially mitigating the toxicity of phosphite to aquatic organisms while exacerbating eutrophication. The findings of this study provide a novel insight into the comprehensive assessment of the environmental fate, potential ecological risk, and biogeochemical behaviors of phosphite in natural aquatic environments under the condition of combined pollution.
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Affiliation(s)
- Qiang Liu
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China; School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming, 525000, PR China
| | - Xiaojun Niu
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China; School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming, 525000, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, PR China.
| | - Dongqing Zhang
- School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming, 525000, PR China.
| | - Xingyao Ye
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China
| | - Peibing Tan
- School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming, 525000, PR China
| | - Ting Shu
- School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming, 525000, PR China
| | - Zhang Lin
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China
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Liao W, Xu R, Stone AT. Adsorption of Phosphorus Oxyanions at the FeOOH(goethite)/Water Interface: The Importance of Basicity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:14389-14396. [PMID: 34477376 DOI: 10.1021/acs.est.1c03734] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
PIII-containing H-phosphonate (HPO32-) and its monoethyl ester (fosetyl), essential pesticides for control of oomycete and fungal pathogens, are among the few pesticides transported by both xylem and phloem, making application as folia spray, soil spray, and trunk injection equally effective. To understand bioavailability and efficacy within soils, knowledge of adsorption to soil minerals is important. FeOOH(goethite) is often selected as an archetypal mineral surface. In the present work, H-phosphonate (with pKa values of 1.5 and 6.78) adsorption onto FeOOH is nearly complete below pH 6 and decreases to negligible amounts by pH 11, following an S-shaped curve. Fosetyl (pKa: 0.9), in contrast, does not adsorb to any significant extent, regardless of pH. To place these observations in context, adsorption of six other phosphorus oxyanions was investigated, and fitted using a CD-MUSIC model. Phosphate defines a similar S-shaped curve but adsorbs more strongly than H-phosphonate. Despite moderate differences in basicity, pH dependence and extents of adsorption for the four additional diprotic oxyanions methylphosphonate (pKas: 2.40, 8.00), benzylphosphonate (2.24, 7.93), phenylphosphonate (1.9, 7.47), and phenyl phosphate (1.1, 6.28) are quite similar to those of H-phosphonate. As with fosetyl, the other low pKa monoprotic oxyanion in our study, phenylphosphinate (pKa: 1.75), does not adsorb. Basicity, that is, pKa, is revealed to be the principal determinant of extents of adsorption.
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Affiliation(s)
- Weichen Liao
- Department of Environmental Health and Engineering G.W.C. Whiting School of Engineering Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Ruizhe Xu
- Department of Civil, Architectural and Environmental Engineering Cockrell School of Engineering The University of Texas at Austin, Austin, Texas 78712, United States
| | - Alan T Stone
- Department of Environmental Health and Engineering G.W.C. Whiting School of Engineering Johns Hopkins University, Baltimore, Maryland 21218, United States
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Ewens SD, Gomberg AFS, Barnum TP, Borton MA, Carlson HK, Wrighton KC, Coates JD. The diversity and evolution of microbial dissimilatory phosphite oxidation. Proc Natl Acad Sci U S A 2021; 118:e2020024118. [PMID: 33688048 PMCID: PMC7980464 DOI: 10.1073/pnas.2020024118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phosphite is the most energetically favorable chemotrophic electron donor known, with a half-cell potential (Eo') of -650 mV for the PO43-/PO33- couple. Since the discovery of microbial dissimilatory phosphite oxidation (DPO) in 2000, the environmental distribution, evolution, and diversity of DPO microorganisms (DPOMs) have remained enigmatic, as only two species have been identified. Here, metagenomic sequencing of phosphite-enriched microbial communities enabled the genome reconstruction and metabolic characterization of 21 additional DPOMs. These DPOMs spanned six classes of bacteria, including the Negativicutes, Desulfotomaculia, Synergistia, Syntrophia, Desulfobacteria, and Desulfomonilia_A Comparing the DPO genes from the genomes of enriched organisms with over 17,000 publicly available metagenomes revealed the global existence of this metabolism in diverse anoxic environments, including wastewaters, sediments, and subsurface aquifers. Despite their newfound environmental and taxonomic diversity, metagenomic analyses suggested that the typical DPOM is a chemolithoautotroph that occupies low-oxygen environments and specializes in phosphite oxidation coupled to CO2 reduction. Phylogenetic analyses indicated that the DPO genes form a highly conserved cluster that likely has ancient origins predating the split of monoderm and diderm bacteria. By coupling microbial cultivation strategies with metagenomics, these studies highlighted the unsampled metabolic versatility latent in microbial communities. We have uncovered the unexpected prevalence, diversity, biochemical specialization, and ancient origins of a unique metabolism central to the redox cycling of phosphorus, a primary nutrient on Earth.
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Affiliation(s)
- Sophia D Ewens
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
- Energy & Biosciences Institute, University of California, Berkeley, CA 94720
| | - Alexa F S Gomberg
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Tyler P Barnum
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Mikayla A Borton
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO 80523
| | - Hans K Carlson
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Kelly C Wrighton
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO 80523
| | - John D Coates
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720;
- Energy & Biosciences Institute, University of California, Berkeley, CA 94720
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
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5
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Yang Y, Wu W, Wang Z, Huang L, Ma X, Zhang Z, Xiang S. UiO‐66/GO Composites with Improved Electrochemical Properties for Effective Detection of Phosphite(P(III)) in Phosphate(P(V)) Buffer Solutions. ChemistrySelect 2020. [DOI: 10.1002/slct.202002594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ying Yang
- Fujian Provincial Key Laboratory of Polymer Materials College of Chemistry and Materials Science, Fujian Normal University 32 Shangshan Road Fuzhou 350007 PR China
| | - Wangui Wu
- Fujian Provincial Key Laboratory of Polymer Materials College of Chemistry and Materials Science, Fujian Normal University 32 Shangshan Road Fuzhou 350007 PR China
| | - Ziyan Wang
- Fujian Provincial Key Laboratory of Polymer Materials College of Chemistry and Materials Science, Fujian Normal University 32 Shangshan Road Fuzhou 350007 PR China
| | - Limei Huang
- Fujian Provincial Key Laboratory of Polymer Materials College of Chemistry and Materials Science, Fujian Normal University 32 Shangshan Road Fuzhou 350007 PR China
| | - Xiuling Ma
- Fujian Provincial Key Laboratory of Polymer Materials College of Chemistry and Materials Science, Fujian Normal University 32 Shangshan Road Fuzhou 350007 PR China
| | - Zhangjing Zhang
- Fujian Provincial Key Laboratory of Polymer Materials College of Chemistry and Materials Science, Fujian Normal University 32 Shangshan Road Fuzhou 350007 PR China
- State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou Fujian 350002 PR China
| | - Shengchang Xiang
- Fujian Provincial Key Laboratory of Polymer Materials College of Chemistry and Materials Science, Fujian Normal University 32 Shangshan Road Fuzhou 350007 PR China
- State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou Fujian 350002 PR China
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Sousa-Silva C, Seager S, Ranjan S, Petkowski JJ, Zhan Z, Hu R, Bains W. Phosphine as a Biosignature Gas in Exoplanet Atmospheres. ASTROBIOLOGY 2020; 20:235-268. [PMID: 31755740 DOI: 10.1089/ast.2018.1954] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A long-term goal of exoplanet studies is the identification and detection of biosignature gases. Beyond the most discussed biosignature gas O2, only a handful of gases have been considered in detail. In this study, we evaluate phosphine (PH3). On Earth, PH3 is associated with anaerobic ecosystems, and as such, it is a potential biosignature gas in anoxic exoplanets. We simulate the atmospheres of habitable terrestrial planets with CO2- and H2-dominated atmospheres and find that PH3 can accumulate to detectable concentrations on planets with surface production fluxes of 1010 to 1014 cm-2 s-1 (corresponding to surface concentrations of 10s of ppb to 100s of ppm), depending on atmospheric composition and ultraviolet (UV) irradiation. While high, the surface flux values are comparable to the global terrestrial production rate of methane or CH4 (1011 cm-2 s-1) and below the maximum local terrestrial PH3 production rate (1014 cm-2 s-1). As with other gases, PH3 can more readily accumulate on low-UV planets, for example, planets orbiting quiet M dwarfs or with a photochemically generated UV shield. PH3 has three strong spectral features such that in any atmosphere scenario one of the three will be unique compared with other dominant spectroscopic molecules. Phosphine's weakness as a biosignature gas is its high reactivity, requiring high outgassing rates for detectability. We calculate that tens of hours of JWST (James Webb Space Telescope) time are required for a potential detection of PH3. Yet, because PH3 is spectrally active in the same wavelength regions as other atmospherically important molecules (such as H2O and CH4), searches for PH3 can be carried out at no additional observational cost to searches for other molecular species relevant to characterizing exoplanet habitability. Phosphine is a promising biosignature gas, as it has no known abiotic false positives on terrestrial planets from any source that could generate the high fluxes required for detection.
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Affiliation(s)
- Clara Sousa-Silva
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts
- Department of Physics, and Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts
| | - Sara Seager
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts
- Department of Physics, and Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts
| | - Sukrit Ranjan
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts
- SCOL Postdoctoral Fellow
| | - Janusz Jurand Petkowski
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts
| | - Zhuchang Zhan
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts
| | - Renyu Hu
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California
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7
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Chang Y, Liu M, Liu J. Highly Selective Fluorescent Sensing of Phosphite through Recovery of Poisoned Nickel Oxide Nanozyme. Anal Chem 2020; 92:3118-3124. [DOI: 10.1021/acs.analchem.9b04736] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Yangyang Chang
- School of Environmental Science and Technology, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), Dalian University of Technology, Dalian 116024, China
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Meng Liu
- School of Environmental Science and Technology, Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), Dalian University of Technology, Dalian 116024, China
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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8
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Figueroa IA, Barnum TP, Somasekhar PY, Carlström CI, Engelbrektson AL, Coates JD. Metagenomics-guided analysis of microbial chemolithoautotrophic phosphite oxidation yields evidence of a seventh natural CO 2 fixation pathway. Proc Natl Acad Sci U S A 2018; 115:E92-E101. [PMID: 29183985 PMCID: PMC5776814 DOI: 10.1073/pnas.1715549114] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dissimilatory phosphite oxidation (DPO), a microbial metabolism by which phosphite (HPO32-) is oxidized to phosphate (PO43-), is the most energetically favorable chemotrophic electron-donating process known. Only one DPO organism has been described to date, and little is known about the environmental relevance of this metabolism. In this study, we used 16S rRNA gene community analysis and genome-resolved metagenomics to characterize anaerobic wastewater treatment sludge enrichments performing DPO coupled to CO2 reduction. We identified an uncultivated DPO bacterium, Candidatus Phosphitivorax (Ca. P.) anaerolimi strain Phox-21, that belongs to candidate order GW-28 within the Deltaproteobacteria, which has no known cultured isolates. Genes for phosphite oxidation and for CO2 reduction to formate were found in the genome of Ca. P. anaerolimi, but it appears to lack any of the known natural carbon fixation pathways. These observations led us to propose a metabolic model for autotrophic growth by Ca. P. anaerolimi whereby DPO drives CO2 reduction to formate, which is then assimilated into biomass via the reductive glycine pathway.
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Affiliation(s)
- Israel A Figueroa
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Tyler P Barnum
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Pranav Y Somasekhar
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Charlotte I Carlström
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Anna L Engelbrektson
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - John D Coates
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
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Qiu H, Geng J, Ren H, Ding L, Xu K, Zhang Y. Aquatic transformation of phosphite under natural sunlight and simulated irradiation. WATER RESEARCH 2017; 109:69-76. [PMID: 27866104 DOI: 10.1016/j.watres.2016.11.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 10/24/2016] [Accepted: 11/05/2016] [Indexed: 06/06/2023]
Abstract
The phototransformation of phosphite (HPO32-, H2PO3-, +3) from Lake Taihu water (THW) under natural sunlight was evaluated. No direct phosphite photoreaction was observed under sunlight. Suspended solids were shown to play important roles in the indirect photoreaction of phosphite in lake water. The phototransformation of phosphite followed pseudo-first-order reaction kinetics and the kinetics constants (k, d-1) decreased as: 0.0324 (original THW), 0.0236 (sterilized THW), 0.0109 (filtered THW) and 0.0102 (sterilized filtered THW). Original THW with 1 mmol L-1 NO3- added was used to simulate the phosphite removal in lakes with serious N pollution. The results showed that the phototransformation was accelerated (with k increased to 0.0386-0.0463 d-1), and sterilization or filtration shown little effect to the transformation, as the half-lives of phosphite drew closer. Under simulated irradiation in NO3- system, increasing NO3- concentration or decreasing pH value promoted phototransformation. The addition of Fe3+ or Fe2+ accelerated photooxidation, while the addition of Mn2+ or Cd2+ inhibited phototransformation. Br-, NO2- and HCO3- in environmental concentrations decreased phototransformation, and HCO3- showed the strongest inhibition. Suwannee River humic acid or Suwannee River fulvic acid strongly inhibited the photooxidation process, and the inhibiting effects varied with their structure. Phosphite photooxidation was strongly inhibited by adding isopropanol or sodium azide as reactive oxygen species (ROS) quenchers. Electron spin resonance analysis indicated that OH was a main oxidant produced in this system. The increased amount of phosphate coincided with the decreased amount of phosphite, which indicated that the transformation product of phosphite was phosphate. Phosphite is a considerable component of the P redox cycle in Lake Taihu.
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Affiliation(s)
- Huimin Qiu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Jinju Geng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
| | - Hongqiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Lili Ding
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Ke Xu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Yan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
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Figueroa IA, Coates JD. Microbial Phosphite Oxidation and Its Potential Role in the Global Phosphorus and Carbon Cycles. ADVANCES IN APPLIED MICROBIOLOGY 2016; 98:93-117. [PMID: 28189156 DOI: 10.1016/bs.aambs.2016.09.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Phosphite [Formula: see text] is a highly soluble, reduced phosphorus compound that is often overlooked in biogeochemical analyses. Although the oxidation of phosphite to phosphate is a highly exergonic process (Eo'=-650mV), phosphite is kinetically stable and can account for 10-30% of the total dissolved P in various environments. There is also evidence that phosphite was more prevalent under the reducing conditions of the Archean period and may have been involved in the development of early life. Its role as a phosphorus source for a variety of extant microorganisms has been known since the 1950s, and the pathways involved in assimilatory phosphite oxidation have been well characterized. More recently, it was demonstrated that phosphite could also act as an electron donor for energy metabolism in a process known as dissimilatory phosphite oxidation (DPO). The bacterium described in this study, Desulfotignum phosphitoxidans strain FiPS-3, was isolated from brackish sediments and is capable of growing by coupling phosphite oxidation to the reduction of either sulfate or carbon dioxide. FiPS-3 remains the only isolated organism capable of DPO, and the prevalence of this metabolism in the environment is still unclear. Nonetheless, given the widespread presence of phosphite in the environment and the thermodynamic favorability of its oxidation, microbial phosphite oxidation may play an important and hitherto unrecognized role in the global phosphorus and carbon cycles.
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Affiliation(s)
- I A Figueroa
- University of California, Berkeley, CA, United States
| | - J D Coates
- University of California, Berkeley, CA, United States
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Qiu H, Geng J, Ren H, Xu Z. Phosphite flux at the sediment-water interface in northern Lake Taihu. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 543:67-74. [PMID: 26580728 DOI: 10.1016/j.scitotenv.2015.10.136] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Revised: 10/23/2015] [Accepted: 10/27/2015] [Indexed: 06/05/2023]
Abstract
Phosphite (H2PO3(-), HPO3(2-), +3 valence), a reduced form of phosphorus (P), has been widely detected in water environments. The role of phosphite in the P biogeochemical cycle has not been investigated systematically and quantitative results on phosphite fluxes are lacking. In this study, intact sediment core simulation was employed to measure the flux of phosphite at the sediment-water interface in northern Lake Taihu. Phosphite fluxes (μmol m(-2) d(-1)) ranged from -38.21±1.14 to 7.10±2.18, with an annual average of -4.72±10.40. On the whole, phosphite migrated from water into sediment and the sediment was primarily a sink. The highest seasonal negative phosphite fluxes (μmol m(-2) d(-1)) occurred in winter (-10.44±18.63), followed by summer (-8.04±5.61) and spring (-2.61±4.17). In autumn, phosphite flux was 2.20±4.07. Higher annual average negative fluxes of phosphite (μmol m(-2) d(-1)) appeared in site ZSB (-12.70±17.96), which contained the highest content of total soluble P. The average yearly migration of phosphite in Lake Taihu from water to sediment was estimated to be (4.04±8.88)×10(6) mol y(-1). The transfer of phosphite from water into sediment usually occurs in winter may due to the season's natural tendency to create more favorable conditions for phosphite biogeochemical reactions. Phosphite fluxes showed significant negative correlations with the original phosphite concentration in water (r=-0.840, p<0.01), as well as organic matter (r=-0.720, p<0.01) and phosphate bound to Ca (Ca-Ps) (r=-0.632, p<0.05) in sediment. These results indicate that microbiological processes and P species bound to Ca may play an important role in the P redox cycle. No significant correlations between phosphite fluxes and dissolved oxygen or oxidation-reduction potential were observed.
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Affiliation(s)
- Huimin Qiu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, China
| | - Jinju Geng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, China.
| | - Hongqiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, China
| | - Zhaoyi Xu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, China
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