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A Novel Regulator Participating in Nitrogen Removal Process of Bacillus subtilis JD-014. Int J Mol Sci 2021; 22:ijms22126543. [PMID: 34207153 PMCID: PMC8234713 DOI: 10.3390/ijms22126543] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/02/2021] [Accepted: 06/07/2021] [Indexed: 12/02/2022] Open
Abstract
Aerobic denitrification is considered as a promising biological method to eliminate the nitrate contaminants in waterbodies. However, the molecular mechanism of this process varies in different functional bacteria. In this study, the nitrogen removal characteristics for a newly isolated aerobic denitrifier Bacillus subtilis JD-014 were investigated, and the potential functional genes involved in the aerobic denitrification process were further screened through transcriptome analysis. JD-014 exhibited efficient denitrification performance when having sodium succinate as the carbon source with the range of nitrate concentration between 50 and 300 mg/L. Following the transcriptome data, most of the up-regulated differentially expressed genes (DEGs) were associated with cell motility, carbohydrate metabolism, and energy metabolism. Moreover, gene nirsir annotated as sulfite reductase was screened out and further identified as a regulator participating in the nitrogen removal process within JD-014. The findings in present study provide meaningful information in terms of a comprehensive understanding of genetic regulation of nitrogen metabolism, especially for Bacillus strains.
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102
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Phylogeny and Evolutionary History of Respiratory Complex I Proteins in Melainabacteria. Genes (Basel) 2021; 12:genes12060929. [PMID: 34207155 PMCID: PMC8235220 DOI: 10.3390/genes12060929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 12/13/2022] Open
Abstract
The evolution of oxygenic photosynthesis was one of the most transformative evolutionary events in Earth's history, leading eventually to the oxygenation of Earth's atmosphere and, consequently, the evolution of aerobic respiration. Previous work has shown that the terminal electron acceptors (complex IV) of aerobic respiration likely evolved after the evolution of oxygenic photosynthesis. However, complex I of the respiratory complex chain can be involved in anaerobic processes and, therefore, may have pre-dated the evolution of oxygenic photosynthesis. If so, aerobic respiration may have built upon respiratory chains that pre-date the rise of oxygen in Earth's atmosphere. The Melainabacteria provide a unique opportunity to examine this hypothesis because they contain genes for aerobic respiration but likely diverged from the Cyanobacteria before the evolution of oxygenic photosynthesis. Here, we examine the phylogenies of translated complex I sequences from 44 recently published Melainabacteria metagenome assembled genomes and genomes from other Melainabacteria, Cyanobacteria, and other bacterial groups to examine the evolutionary history of complex I. We find that complex I appears to have been present in the common ancestor of Melainabacteria and Cyanobacteria, supporting the idea that aerobic respiration built upon respiratory chains that pre-date the evolution of oxygenic photosynthesis and the rise of oxygen.
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103
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Zhang Y, Zhang Z, Chen Y. Biochar Mitigates N 2O Emission of Microbial Denitrification through Modulating Carbon Metabolism and Allocation of Reducing Power. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:8068-8078. [PMID: 34029075 DOI: 10.1021/acs.est.1c01976] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
To elucidate the direct effects of biochar on denitrification metabolism at the cellular level, the global response of model denitrifying soil bacterium (Paracoccus denitrificans) to biochar addition was investigated by physiological, proteomic, and metabolomics analyses. The enhancement effect on denitrification was positively correlated with its pyrolysis temperatures (300-500 °C) and dosages (0.1-1%), regardless of precursors [corn straw (CS) or wheat straw). Moreover, the stimulating effect of CS biochar made at 500 °C (CS-500) was mainly attributed to the bulk particles rather than the released soluble compounds. Without direct contact with cells, bulk CS-500 particles might directly modulate the carbon metabolism by the adsorption of extracellular metabolites. Since carbon flux to storage was shifted to oxidative catabolism and growth assimilation, more share of the produced reducing power was used for nitrogen reduction. Meanwhile, except for nitrate reductase, both protein expressions and enzyme activities of nitrite reductase, nitric oxide reductase, and nitrous oxide reductase were up-regulated. Accordingly, the accumulation of N2O was reduced by 98% due to the optimized electron distribution among denitrifying enzymes. Eventually, the growth rate of Pc. denitrificans enhanced because of the improved energy utilization efficiency. These results updated the regulation mechanism of biochar on denitrification metabolism and N2O mitigation.
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Affiliation(s)
- Yu Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Zhengzhe Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
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104
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Hu B, Quan J, Huang K, Zhao J, Xing G, Wu P, Chen Y, Ding X, Hu Y. Effects of C/N ratio and dissolved oxygen on aerobic denitrification process: A mathematical modeling study. CHEMOSPHERE 2021; 272:129521. [PMID: 33485044 DOI: 10.1016/j.chemosphere.2020.129521] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 12/26/2020] [Accepted: 12/28/2020] [Indexed: 06/12/2023]
Abstract
COD to ammonium nitrogen (C/N) ratio and dissolved oxygen (DO) concentration are the most important factors affecting aerobic denitrification process, however, the effects of those on the mix-cultured aerobic denitrification process are still ambiguous. A mathematical model based on the framework of activated sludge model No. 3 (ASM3) was proposed for simulating nitrogen removal in an aerobic denitrification SBR process via anoxic/aerobic denitrification. AQUASIM 2.1G was employed for parameter estimation, sensitivity analysis and model calibration, as well as model validation. Ultimately, the impacts of the C/N ratio and the DO concentration on the aerobic denitrification process were revealed by the validated model. The model proposed well described nitrogen removal in an aerobic denitrification SBR process. The total nitrogen (TN) removal efficiency of the process increased with the increasing of C/N ratio and the decreasing of DO concentration. C/N ratio impacted the synthesis of cell internal storage products (XSTO), and the effects of DO concentration on the process resulted from the competition with substrate between heterotrophs and aerobic denitrifiers. High C/N ratio was preferred, however, the DO concentration should be maintained at a relatively lower level under the premise of ensuring the aerobic condition.
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Affiliation(s)
- Bo Hu
- School of Civil Engineering, Chang' an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, Chang'an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China.
| | - Jianing Quan
- School of Civil Engineering, Chang' an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, Chang'an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China
| | - Kun Huang
- School of Civil Engineering, Chang' an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, Chang'an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China
| | - Jianqiang Zhao
- Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, Chang'an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China; School of Water and Environment, Chang' an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China
| | - Guohua Xing
- School of Civil Engineering, Chang' an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, Chang'an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China
| | - Pei Wu
- School of Civil Engineering, Chang' an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, Chang'an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China
| | - Ying Chen
- Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, Chang'an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China; School of Water and Environment, Chang' an University, The middle section of the south 2nd ring road, 710064, Xi'an, Shaanxi Province, China
| | - Xiaoqian Ding
- School of Architecture and Civil Engineering, Xi'an University of Science and Technology, Yanta Road No. 58, 710054, Xi'an, Shaanxi Province, China
| | - Yuansheng Hu
- Civil Engineering, College of Engineering and Informatics, National University of Ireland, University Road, H91 TK33, Galway, Ireland
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105
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Shan J, Sanford RA, Chee-Sanford J, Ooi SK, Löffler FE, Konstantinidis KT, Yang WH. Beyond denitrification: The role of microbial diversity in controlling nitrous oxide reduction and soil nitrous oxide emissions. GLOBAL CHANGE BIOLOGY 2021; 27:2669-2683. [PMID: 33547715 DOI: 10.1111/gcb.15545] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 01/11/2021] [Indexed: 05/02/2023]
Abstract
Many biotic and abiotic processes contribute to nitrous oxide (N2 O) production in the biosphere, but N2 O consumption in the environment has heretofore been attributed primarily to canonical denitrifying microorganisms. The nosZ genes encoding the N2 O reductase enzyme, NosZ, responsible for N2 O reduction to dinitrogen are now known to include two distinct groups: the well-studied Clade I which denitrifiers typically possess, and the novel Clade II possessed by diverse groups of microorganisms, most of which are non-denitrifiers. Clade II N2 O reducers could play an important, previously unrecognized role in controlling N2 O emissions for several reasons, including: (1) the consumption of N2 O produced by processes other than denitrification, (2) hypothesized non-respiratory functions of NosZ as an electron sink or for N2 O detoxification, (3) possible differing enzyme kinetics of Clade II NosZ compared to Clade I NosZ, and (4) greater nosZ gene abundance for Clade II compared to Clade I in soils of many ecosystems. Despite the potential ecological significance of Clade II NosZ, a census of 800 peer-reviewed original research articles discussing nosZ and published from 2013 to 2019 showed that the percentage of articles evaluating or mentioning Clade II nosZ increased from 5% in 2013 to only 22% in 2019. The census revealed that the slowly spreading awareness of Clade II nosZ may result in part from disciplinary silos, with the percentage of nosZ articles mentioning Clade II nosZ ranging from 0% in Agriculture and Agronomy journals to 32% in Multidisciplinary Sciences journals. In addition, inconsistent nomenclature for Clade I nosZ and Clade II nosZ, with 17 different terminologies used in the literature, may have created confusion about the two distinct groups of N2 O reducers. We provide recommendations to accelerate advances in understanding the role of the diversity of N2 O reducers in regulating soil N2 O emissions.
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Affiliation(s)
- Jun Shan
- State Key Laboratory of Soil and Sustainable Agriculture, Changshu National Agro-Ecosystem Observation and Research Station, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Robert A Sanford
- Department of Geology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Joanne Chee-Sanford
- Global Change and Photosynthesis Research Unit, United States Department of Agriculture - Agricultural Research Station,, Urbana, IL, USA
| | - Sean K Ooi
- Program in Ecology, Evolution, and Conservation Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Frank E Löffler
- Center for Environmental Biotechnology, Department of Microbiology, Department of Civil and Environmental Engineering, Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Konstantinos T Konstantinidis
- School of Civil and Environmental Engineering and School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Wendy H Yang
- Departments of Plant Biology and Geology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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106
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Guadie A, Han JL, Liu W, Ding YC, Minale M, Ajibade FO, Zhai S, Wang HC, Cheng H, Ren N, Wang A. Evaluating the effect of fenton pretreated pyridine wastewater under different biological conditions: Microbial diversity and biotransformation pathways. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 287:112297. [PMID: 33706088 DOI: 10.1016/j.jenvman.2021.112297] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 02/19/2021] [Accepted: 02/26/2021] [Indexed: 06/12/2023]
Abstract
Pyridine contamination poses a significant threat to human and environmental health. Due to the presence of nitrogen atom in the pyridine ring, the pi bond electrons are attracted toward it and make difficult for pyridine treatment with biological and chemical methods. In this study, coupling Fenton treatment with different biological process was designed to enhance pyridine biotransformation and further mineralization. After Fenton oxidation process optimized, pretreated pyridine was evaluated under three biological (anaerobic, aerobic and microaerobic) operating conditions. Under optimum Fenton oxidation, pyridine (30-75%) and TOC (5-25%) removal efficiencies were poor. Biological process alone also showed insignificant removal efficiency, particularly anaerobic (pyridine = 8.2%; TOC = 5.3%) culturing condition. However, combining Fenton pretreatment with biological process increased pyridine (93-99%) and TOC (87-93%) removals, suggesting that hydroxyl radical generated during Fenton oxidation enhanced pyridine hydroxylation and further mineralization in the biological (aerobic > microaerobic > anaerobic) process. Intermediates were analyzed with UPLC-MS and showed presence of maleic acid, pyruvic acid, glutaric dialdehyde, succinic semialdehyde and 4-formylamino-butyric acid. High-throughput sequencing analysis also indicated that Proteobacteria (35-43%) followed by Chloroflexi (10.6-24.3%) and Acidobacteria (8.0-29%) were the dominant phyla detected in the three biological treatment conditions. Co-existence of dominant genera under aerobic/microaerobic (Nitrospira > Dokdonella > Caldilinea) and anaerobic (Nitrospira > Caldilinea > Longilinea) systems most probably play significant role in biotransformation of pyridine and its intermediate products. Overall, integrating Fenton pretreatment with different biological process is a promising technology for pyridine treatment, especially the combined system enhanced anaerobic (>10 times) microbial pyridine biotransformation activity.
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Affiliation(s)
- Awoke Guadie
- Key Laboratory of Environmental Biotechnology Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Department of Biology, College of Natural Sciences, Arba Minch University, Arba Minch 21, Ethiopia
| | - Jing-Long Han
- School of Civil & Environmental Engineering, Harbin Institute of Technology, Shenzhen, 518055, China.
| | - Wenzong Liu
- Key Laboratory of Environmental Biotechnology Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; School of Civil & Environmental Engineering, Harbin Institute of Technology, Shenzhen, 518055, China
| | - Yang-Cheng Ding
- Key Laboratory of Environmental Biotechnology Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Mengist Minale
- UNEP-Tongji Institute of Environment for Sustainable Development, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Fidelis O Ajibade
- Key Laboratory of Environmental Biotechnology Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Siyuan Zhai
- Key Laboratory of Environmental Biotechnology Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Hong-Cheng Wang
- Key Laboratory of Environmental Biotechnology Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Haoyi Cheng
- Key Laboratory of Environmental Biotechnology Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Nanqi Ren
- School of Civil & Environmental Engineering, Harbin Institute of Technology, Shenzhen, 518055, China
| | - Aijie Wang
- Key Laboratory of Environmental Biotechnology Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; School of Civil & Environmental Engineering, Harbin Institute of Technology, Shenzhen, 518055, China
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107
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No-Till and Solid Digestate Amendment Selectively Affect the Potential Denitrification Activity in Two Mediterranean Orchard Soils. SOIL SYSTEMS 2021. [DOI: 10.3390/soilsystems5020031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Improved soil managements that include reduced soil disturbance and organic amendment incorporation represent valuable strategies to counteract soil degradation processes that affect Mediterranean tree cultivations. However, changes induced by these practices can promote soil N loss through denitrification. Our research aimed to investigate the short-term effects of no-tillage and organic amendment with solid anaerobic digestate on the potential denitrification in two Mediterranean orchard soils showing contrasting properties in terms of texture and pH. Denitrifying enzyme activity (DEA) and selected soil variables (available C and N, microbial biomass C, basal respiration) were monitored in olive and orange tree orchard soils over a five-month period. Our results showed that the application of both practices increased soil DEA, with dynamics that varied according to the soil type. Increased bulk density, lowered soil aeration, and a promoting effect on soil microbial community growth were the main DEA triggers under no-tillage. Conversely, addition of digestate promoted DEA by increasing readily available C and N with a shorter effect in the olive grove soil, due to greater sorption and higher microbial efficiency, and a long-lasting consequence in the orange orchard soil related to a larger release of soluble substrates and their lower microbial use efficiency.
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108
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Shen L, Gao L, Yang M, Zhang J, Wang Y, Feng Y, Wang L, Wang S. Deletion of the PA4427-PA4431 Operon of Pseudomonas aeruginosa PAO1 Increased Antibiotics Resistance and Reduced Virulence and Pathogenicity by Affecting Quorum Sensing and Iron Uptake. Microorganisms 2021; 9:microorganisms9051065. [PMID: 34069209 PMCID: PMC8156433 DOI: 10.3390/microorganisms9051065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/06/2021] [Accepted: 05/10/2021] [Indexed: 12/06/2022] Open
Abstract
The respiratory chain is very important for bacterial survival and pathogenicity, yet the roles of the respiratory chain in P. aeruginosa remain to be fully elucidated. Here, we not only proved experimentally that the operon PA4427-PA4431 of Pseudomonas aeruginosa PAO1 encodes respiratory chain complex III (cytobc1), but also found that it played important roles in virulence and pathogenicity. PA4429–31 deletion reduced the production of the virulence factors, including pyocyanin, rhamnolipids, elastase, and extracellular polysaccharides, and it resulted in a remarkable decrease in pathogenicity, as demonstrated in the cabbage and Drosophila melanogaster infection models. Furthermore, RNA-seq analysis showed that PA4429–31 deletion affected the expression levels of the genes related to quorum-sensing systems and the transport of iron ions, and the iron content was also reduced in the mutant strain. Taken together, we comprehensively illustrated the function of the operon PA4427–31 and its application potential as a treatment target in P. aeruginosa infection.
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109
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Gomaa F, Utter DR, Powers C, Beaudoin DJ, Edgcomb VP, Filipsson HL, Hansel CM, Wankel SD, Zhang Y, Bernhard JM. Multiple integrated metabolic strategies allow foraminiferan protists to thrive in anoxic marine sediments. SCIENCE ADVANCES 2021; 7:7/22/eabf1586. [PMID: 34039603 PMCID: PMC8153729 DOI: 10.1126/sciadv.abf1586] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 04/05/2021] [Indexed: 05/14/2023]
Abstract
Oceanic deoxygenation is increasingly affecting marine ecosystems; many taxa will be severely challenged, yet certain nominally aerobic foraminifera (rhizarian protists) thrive in oxygen-depleted to anoxic, sometimes sulfidic, sediments uninhabitable to most eukaryotes. Gene expression analyses of foraminifera common to severely hypoxic or anoxic sediments identified metabolic strategies used by this abundant taxon. In field-collected and laboratory-incubated samples, foraminifera expressed denitrification genes regardless of oxygen regime with a putative nitric oxide dismutase, a characteristic enzyme of oxygenic denitrification. A pyruvate:ferredoxin oxidoreductase was highly expressed, indicating the capability for anaerobic energy generation during exposure to hypoxia and anoxia. Near-complete expression of a diatom's plastid genome in one foraminiferal species suggests kleptoplasty or sequestration of functional plastids, conferring a metabolic advantage despite the host living far below the euphotic zone. Through a unique integration of functions largely unrecognized among "typical" eukaryotes, benthic foraminifera represent winning microeukaryotes in the face of ongoing oceanic deoxygenation.
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Affiliation(s)
- Fatma Gomaa
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Daniel R Utter
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Christopher Powers
- Department of Cell and Molecular Biology, College of the Environment and Life Sciences, University of Rhode Island, Kingston, RI 02881, USA
| | - David J Beaudoin
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Virginia P Edgcomb
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | | | - Colleen M Hansel
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Scott D Wankel
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Ying Zhang
- Department of Cell and Molecular Biology, College of the Environment and Life Sciences, University of Rhode Island, Kingston, RI 02881, USA
| | - Joan M Bernhard
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
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110
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Cheng C, Zhang J, He Q, Wu H, Chen Y, Xie H, Pavlostathis SG. Exploring simultaneous nitrous oxide and methane sink in wetland sediments under anoxic conditions. WATER RESEARCH 2021; 194:116958. [PMID: 33662685 DOI: 10.1016/j.watres.2021.116958] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/02/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Methane (CH4) and nitrous oxide (N2O) are the most powerful greenhouse gases globally; recent emissions exceed previous estimates. The potential link between N2O reduction and CH4 oxidation in anoxic wetland sediments would be a sink for both gases, which has attracted broad attention. To explore the simultaneous N2O and CH4 biotransformation, wetland sediments were used to inoculate an enrichment reactor, continuously fed with CH4 and N2O for 500 days. After enrichment, the CH4 oxidation rate reached 2.8 μmol·g-1dw·d-1, which was 800-fold higher than the rate of the wetland sediments used as inoculum. Moreover, stable isotopic tracing proved CH4 oxidation was driven by N2O consumption under anoxic conditions. Genomic sequencing showed that the microbial community was dominated by methanotrophs. Species of Methylocaldum genus, belonging to γ-Proteobacteria class, were significantly enriched, and became the predominant methanotrophs. Quantitative analysis indicated methane monooxygenase and nitrous oxide reductase increased by 38- and 8-fold compared to the inoculum. As to the potential mechanisms, we propose that N2O-driven CH4 oxidation was mediated by aerobic methanotrophs solely or along with denitrifying bacteria under hypoxia. Electrons and energy are generated and transferred in the oxidative phosphorylation pathway. Our findings expand the range of electron acceptors associated with CH4 oxidation as well as elucidate the significant role of methanotrophs relative to both carbon and nitrogen cycles.
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Affiliation(s)
- Cheng Cheng
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China; School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China; School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, USA.
| | - Jian Zhang
- School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China.
| | - Qiang He
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Haiming Wu
- School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Yi Chen
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Huijun Xie
- Environmental Research Institute, Shandong University, Qingdao 266237, China
| | - Spyros G Pavlostathis
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, USA
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111
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Gazitúa MC, Vik DR, Roux S, Gregory AC, Bolduc B, Widner B, Mulholland MR, Hallam SJ, Ulloa O, Sullivan MB. Potential virus-mediated nitrogen cycling in oxygen-depleted oceanic waters. THE ISME JOURNAL 2021; 15:981-998. [PMID: 33199808 PMCID: PMC8115048 DOI: 10.1038/s41396-020-00825-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 09/30/2020] [Accepted: 10/27/2020] [Indexed: 01/29/2023]
Abstract
Viruses play an important role in the ecology and biogeochemistry of marine ecosystems. Beyond mortality and gene transfer, viruses can reprogram microbial metabolism during infection by expressing auxiliary metabolic genes (AMGs) involved in photosynthesis, central carbon metabolism, and nutrient cycling. While previous studies have focused on AMG diversity in the sunlit and dark ocean, less is known about the role of viruses in shaping metabolic networks along redox gradients associated with marine oxygen minimum zones (OMZs). Here, we analyzed relatively quantitative viral metagenomic datasets that profiled the oxygen gradient across Eastern Tropical South Pacific (ETSP) OMZ waters, assessing whether OMZ viruses might impact nitrogen (N) cycling via AMGs. Identified viral genomes encoded six N-cycle AMGs associated with denitrification, nitrification, assimilatory nitrate reduction, and nitrite transport. The majority of these AMGs (80%) were identified in T4-like Myoviridae phages, predicted to infect Cyanobacteria and Proteobacteria, or in unclassified archaeal viruses predicted to infect Thaumarchaeota. Four AMGs were exclusive to anoxic waters and had distributions that paralleled homologous microbial genes. Together, these findings suggest viruses modulate N-cycling processes within the ETSP OMZ and may contribute to nitrogen loss throughout the global oceans thus providing a baseline for their inclusion in the ecosystem and geochemical models.
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Affiliation(s)
- M. Consuelo Gazitúa
- grid.261331.40000 0001 2285 7943Department of Microbiology, The Ohio State University, Columbus, OH 43210 USA ,Viromica Consulting, Santiago, Chile
| | - Dean R. Vik
- grid.261331.40000 0001 2285 7943Department of Microbiology, The Ohio State University, Columbus, OH 43210 USA
| | - Simon Roux
- grid.451309.a0000 0004 0449 479XDOE Joint Genome Institute, Berkeley, CA USA
| | - Ann C. Gregory
- grid.261331.40000 0001 2285 7943Department of Microbiology, The Ohio State University, Columbus, OH 43210 USA
| | - Benjamin Bolduc
- grid.261331.40000 0001 2285 7943Department of Microbiology, The Ohio State University, Columbus, OH 43210 USA
| | - Brittany Widner
- grid.261368.80000 0001 2164 3177Department of Ocean, Earth and Atmospheric Sciences, Old Dominion University, Norfolk, VA USA ,grid.56466.370000 0004 0504 7510Woods Hole Oceanographic Institution, Woods Hole, MA USA
| | - Margaret R. Mulholland
- grid.261368.80000 0001 2164 3177Department of Ocean, Earth and Atmospheric Sciences, Old Dominion University, Norfolk, VA USA
| | - Steven J. Hallam
- grid.17091.3e0000 0001 2288 9830Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC Canada
| | - Osvaldo Ulloa
- grid.5380.e0000 0001 2298 9663Departamento de Oceanografía & Instituto Milenio de Oceanografía, Universidad de Concepción, Concepción, Chile
| | - Matthew B. Sullivan
- grid.261331.40000 0001 2285 7943Department of Microbiology, The Ohio State University, Columbus, OH 43210 USA ,grid.261331.40000 0001 2285 7943Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, Columbus, OH USA
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112
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Graf JS, Schorn S, Kitzinger K, Ahmerkamp S, Woehle C, Huettel B, Schubert CJ, Kuypers MMM, Milucka J. Anaerobic endosymbiont generates energy for ciliate host by denitrification. Nature 2021; 591:445-450. [PMID: 33658719 PMCID: PMC7969357 DOI: 10.1038/s41586-021-03297-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/27/2021] [Indexed: 11/27/2022]
Abstract
Mitochondria are specialized eukaryotic organelles that have a dedicated function in oxygen respiration and energy production. They evolved about 2 billion years ago from a free-living bacterial ancestor (probably an alphaproteobacterium), in a process known as endosymbiosis1,2. Many unicellular eukaryotes have since adapted to life in anoxic habitats and their mitochondria have undergone further reductive evolution3. As a result, obligate anaerobic eukaryotes with mitochondrial remnants derive their energy mostly from fermentation4. Here we describe 'Candidatus Azoamicus ciliaticola', which is an obligate endosymbiont of an anaerobic ciliate and has a dedicated role in respiration and providing energy for its eukaryotic host. 'Candidatus A. ciliaticola' contains a highly reduced 0.29-Mb genome that encodes core genes for central information processing, the electron transport chain, a truncated tricarboxylic acid cycle, ATP generation and iron-sulfur cluster biosynthesis. The genome encodes a respiratory denitrification pathway instead of aerobic terminal oxidases, which enables its host to breathe nitrate instead of oxygen. 'Candidatus A. ciliaticola' and its ciliate host represent an example of a symbiosis that is based on the transfer of energy in the form of ATP, rather than nutrition. This discovery raises the possibility that eukaryotes with mitochondrial remnants may secondarily acquire energy-providing endosymbionts to complement or replace functions of their mitochondria.
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Affiliation(s)
- Jon S Graf
- Max Planck Institute for Marine Microbiology, Bremen, Germany.
| | - Sina Schorn
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Katharina Kitzinger
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | | | - Christian Woehle
- Max Planck Genome Centre Cologne, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Bruno Huettel
- Max Planck Genome Centre Cologne, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Carsten J Schubert
- Surface Waters - Research and Management, Eawag, Kastanienbaum, Switzerland
| | | | - Jana Milucka
- Max Planck Institute for Marine Microbiology, Bremen, Germany.
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113
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Su Q, Schittich AR, Jensen MM, Ng H, Smets BF. Role of Ammonia Oxidation in Organic Micropollutant Transformation during Wastewater Treatment: Insights from Molecular, Cellular, and Community Level Observations. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:2173-2188. [PMID: 33543927 DOI: 10.1021/acs.est.0c06466] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Organic micropollutants (OMPs) are a threat to aquatic environments, and wastewater treatment plants may act as a source or a barrier of OMPs entering the environment. Understanding the fate of OMPs in wastewater treatment processes is needed to establish efficient OMP removal strategies. Enhanced OMP biotransformation has been documented during biological nitrogen removal and has been attributed to the cometabolic activity of ammonia-oxidizing bacteria (AOB) and, specifically, to the ammonia monooxygenase (AMO) enzyme. Yet, the exact mechanisms of OMP biotransformation are often unknown. This critical review aims to fundamentally and quantitatively evaluate the role of ammonia oxidation in OMP biotransformation during wastewater treatment processes. OMPs can be transformed by AOB via direct and indirect enzymatic reactions: AMO directly transforms OMPs primarily via hydroxylation, while biologically produced reactive nitrogen species (hydroxylamine (NH2OH), nitrite (NO2-), and nitric oxide (NO)) can chemically transform OMPs through nitration, hydroxylation, and deamination and can contribute significantly to the observed OMP transformations. OMPs containing alkyl, aliphatic hydroxyl, ether, and sulfide functional groups as well as substituted aromatic rings and aromatic primary amines can be biotransformed by AMO, while OMPs containing alkyl groups, phenols, secondary amines, and aromatic primary amines can undergo abiotic transformations mediated by reactive nitrogen species. Higher OMP biotransformation efficiencies and rates are obtained in AOB-dominant microbial communities, especially in autotrophic reactors performing nitrification or nitritation, than in non-AOB-dominant microbial communities. The biotransformations of OMPs in wastewater treatment systems can often be linked to ammonium (NH4+) removal following two central lines of evidence: (i) Similar transformation products (i.e., hydroxylated, nitrated, and desaminated TPs) are detected in wastewater treatment systems as in AOB pure cultures. (ii) Consistency in OMP biotransformation (rbio, μmol/g VSS/d) to NH4+ removal (rNH4+, mol/g VSS/d) rate ratios (rbio/rNH4+) is observed for individual OMPs across different systems with similar rNH4+ and AOB abundances. In this review, we conclude that AOB are the main drivers of OMP biotransformation during wastewater treatment processes. The importance of biologically driven abiotic OMP transformation is quantitatively assessed, and functional groups susceptible to transformations by AMO and reactive nitrogen species are systematically classified. This critical review will improve the prediction of OMP transformation and facilitate the design of efficient OMP removal strategies during wastewater treatment.
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Affiliation(s)
- Qingxian Su
- National University of Singapore Environmental Research Institute, 5A Engineering Drive 1, 117411 Singapore, Singapore
- Department of Environmental Engineering, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark
| | - Anna-Ricarda Schittich
- Department of Environmental Engineering, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark
| | - Marlene Mark Jensen
- Department of Environmental Engineering, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark
| | - Howyong Ng
- National University of Singapore Environmental Research Institute, 5A Engineering Drive 1, 117411 Singapore, Singapore
- Centre for Water Research, Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576 Singapore, Singapore
| | - Barth F Smets
- Department of Environmental Engineering, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark
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114
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Albina P, Durban N, Bertron A, Albrecht A, Robinet JC, Erable B. Nitrate and nitrite bacterial reduction at alkaline pH and high nitrate concentrations, comparison of acetate versus dihydrogen as electron donors. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 280:111859. [PMID: 33352382 DOI: 10.1016/j.jenvman.2020.111859] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 12/03/2020] [Accepted: 12/13/2020] [Indexed: 06/12/2023]
Abstract
This study assesses bacterial denitrification at alkaline pH, up to 12, and high nitrate concentration, up to 400 mM. Two types of electron donors organic (acetate) and inorganic (dihydrogen) were compared. With both types of electron donors, nitrite reduction was the key step, likely to increase the pH and lead to nitrite accumulation. Firstly, an acclimation process was used: nitrate was progressively increased in three cultures set at pH 9, 10, or 11. This method allowed to observe for the first time nitrate reduction up to pH 10 and 100 mM nitrate with dihydrogen, or up to pH 10 and 400 mM nitrate with acetate. Nitrate reduction kinetics were faster in the presence of acetate. To investigate further the impact of the type of electron donor, a transition from acetate to dihydrogen was tested, and the pH evolution was modelled. Denitrification with dihydrogen strongly increases the pH while with acetate the pH evolution depends on the initial pH. The main difference is the production of acidifying CO2 during the acetate oxidation. Finally, the use of long duration cultures with a highly alkaline pH allowed a nitrate reduction up to pH 11.5 with acetate. However, no reduction was possible in hydrogenotrophy as it would have increased the pH further. Instead, bacteria used organic matter from inoculum to reduce nitrate at pH 11.5. Therefore, considering bacterial denitrification in a context of alkaline pH and high nitrate concentration an organic electron donor such as acetate is advantageous.
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Affiliation(s)
- Pierre Albina
- LGC, CNRS, INPT, UPS, Université de Toulouse, Toulouse, France; LMDC, INSA/UPS Génie Civil, Université de Toulouse, 135 Avenue de Rangueil, 31077, Toulouse Cedex 04, France.
| | - Nadège Durban
- LGC, CNRS, INPT, UPS, Université de Toulouse, Toulouse, France; LMDC, INSA/UPS Génie Civil, Université de Toulouse, 135 Avenue de Rangueil, 31077, Toulouse Cedex 04, France
| | - Alexandra Bertron
- LMDC, INSA/UPS Génie Civil, Université de Toulouse, 135 Avenue de Rangueil, 31077, Toulouse Cedex 04, France
| | - Achim Albrecht
- Andra, 1-7 rue Jean-Monet, Châtenay-Malabry, 62298, France
| | | | - Benjamin Erable
- LGC, CNRS, INPT, UPS, Université de Toulouse, Toulouse, France.
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115
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Yuan H, Huang S, Yuan J, You Y, Zhang Y. Characteristics of microbial denitrification under different aeration intensities: Performance, mechanism, and co-occurrence network. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 754:141965. [PMID: 32911146 DOI: 10.1016/j.scitotenv.2020.141965] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/09/2020] [Accepted: 08/23/2020] [Indexed: 06/11/2023]
Abstract
This study aimed to explore how dissolved oxygen (DO) affected the characteristics and mechanisms of denitrification in mixed bacterial consortia. We analyzed denitrification efficiency, intracellular nicotinamide adenine dinucleotide (NADH), relative expression of functional genes, and potential co-occurrence network of microorganisms. Results showed that the total nitrogen (TN) removal rates at different aeration intensities (0.00, 0.25, 0.63, and 1.25 L/(L·min)) were 0.93, 1.45, 0.86, and 0.53 mg/(L·min), respectively, which were higher than previously reported values for pure culture. The optimal aeration intensity was 0.25 L/(L·min), at which the maximum NADH accumulation rate and highest relative abundance of napA, nirK, and nosZ were achieved. With increased aeration intensity, the amount of electron flux to nitrate decreased and nitrate assimilation increased. On one hand, nitrate reduction was primarily inhibited by oxygen through competition for electron donors of a certain single strain. On the other hand, oxygen was consumed rapidly by bacteria by stimulating carbon metabolism to create an optimal denitrification niche for denitrifying microorganisms. Denitrification was performed via inter-genus cooperation (competitive interactions and symbiotic relationships) between keystone taxa (Azoarcus, Paracoccus, Thauera, Stappia, and Pseudomonas) and other heterotrophic bacteria (OHB) in aeration reactors. However, in the non-aeration case, which was primarily carried out based on intra-genus syntrophy within genus Propionivibrio, the co-occurrence network constructed the optimal niche contributing to the high TN removal efficiency. Overall, this study enhanced our knowledge about the molecular ecological mechanisms of aerobic denitrification in mixed bacterial consortia and has theoretical guiding significance for further practical application.
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Affiliation(s)
- Haiguang Yuan
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Guangzhou 510006, PR China; Guangdong Ecological Environment Control Engineering Technology Research Center, South China University of Technology, Higher Education Mega Center, Guangzhou 510006, PR China
| | - Shaobin Huang
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Guangzhou 510006, PR China; Guangdong Ecological Environment Control Engineering Technology Research Center, South China University of Technology, Higher Education Mega Center, Guangzhou 510006, PR China; State Key Laboratory of Pulp and Paper Engineering, Plant Micro/Nano Fiber Research Center, South China University of Technology, Guangzhou 510640, PR China.
| | - Jianqi Yuan
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Guangzhou 510006, PR China; Guangdong Ecological Environment Control Engineering Technology Research Center, South China University of Technology, Higher Education Mega Center, Guangzhou 510006, PR China
| | - Yingying You
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Guangzhou 510006, PR China; Guangdong Ecological Environment Control Engineering Technology Research Center, South China University of Technology, Higher Education Mega Center, Guangzhou 510006, PR China
| | - Yongqing Zhang
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Guangzhou 510006, PR China
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116
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Jia Y, Qian D, Chen Y, Hu Y. Intra/extracellular electron transfer for aerobic denitrification mediated by in-situ biosynthesis palladium nanoparticles. WATER RESEARCH 2021; 189:116612. [PMID: 33189971 DOI: 10.1016/j.watres.2020.116612] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/31/2020] [Accepted: 11/05/2020] [Indexed: 06/11/2023]
Abstract
The slow electron transfer rate is the bottleneck to the biological wastewater treatment process, and the nanoparticles (NPs) has been verified as a feasible strategy to improve the biological degradation efficiency by accelerating the electron transfer. Here, we employed the Gram-positive Bacillus megaterium Y-4, capable of synthetizing Pd(0), to investigate the intra/extracellular electron transfer (IET/EET) mechanisms mediated by NPs in aerobic denitrification for the first time. Kinetic and thermodynamic results showed that the bio-Pd(0) could significantly promote the removal of both nitrate and nitrite by improving affinity and decreasing activation energy. The enzymic activity and the respiration chain inhibition experiment indicated that the bio-Pd(0) could facilitate the nitrate biotic reduction by improving the Fe-S center activity and serving as parallel H carriers to replace coenzyme Q to selectively increase the electron flux toward nitrate in IET, while promoting the nitrite reduction by abiotic catalysis. Most importantly, the detection of DPV peak at -226~-287 mV proved that the one-electron EET via multiheme cytochrome-bound flavins also occurred in Gram-positive bacteria and enhanced in Pd-loaded cells. In addition, the remarkable increase of the formal charge in EPS indicated that the bio-Pd(0) could act as an electron shuttle to increase the redox site in EPS, eventually accelerating the electron hopping in long-distance electron transfer. Overall, this study expanded our understanding of the roles of bio-Pd(0) on the aerobic denitrification process and provided an insight into the IET/EET of Gram-positive strains.
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Affiliation(s)
- Yating Jia
- Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China
| | - Danshi Qian
- Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China
| | - Yuancai Chen
- Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China.
| | - Yongyou Hu
- Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China
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117
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Chen C, Wang Z, Zhao M, Yuan B, Yao J, Chen J, Hrynshpan D, Savitskaya T. A fungus-bacterium co-culture synergistically promoted nitrogen removal by enhancing enzyme activity and electron transfer. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 754:142109. [PMID: 32898784 DOI: 10.1016/j.scitotenv.2020.142109] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 08/21/2020] [Accepted: 08/29/2020] [Indexed: 06/11/2023]
Abstract
The fungus Penicillium citrinum WXP-2 and the bacterium Citrobacter freundii WXP-9 were isolated and found to have poor denitrification performance. Surprisingly, co-culture of the two strains which formed fungus-bacterium pellets (FBPs) promoted the removal efficiency of nitrate (NO3--N; 95.78%) and total nitrogen (TN; 81.73%). Nitrogen balance analysis showed that excess degraded NO3--N was primarily converted to N2 (77.53%). Moreover, co-culture increased the dry weight to 0.74 g/L. The diameter of pellets and cell viability also increased by 1.49 and 1.78 times, respectively, indicating that the co-culture exerted a synergistic effect to promote growth. The increase in electron-transmission system activity [99.01 mg iodonitrotetrazolium formazan/(g·L)] and nitrate reductase activity [8.65 mg N/(min·mg protein)] were responsible for denitrification promotion. The FBPs also exhibited the highest degradation rate at 2:1 inoculation ratio and 36 h delayed inoculation of strain WXP-9. Finally, recycling experiments of FBP demonstrated that the high steady TN removal rate could be maintained for five cycles.
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Affiliation(s)
- Cong Chen
- College of Environmental, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Zeyu Wang
- Interdisciplinary Research Academy, Zhejiang Shuren University, Hangzhou 310015, PR China
| | - Min Zhao
- College of Environmental, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Bohan Yuan
- College of Environmental, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Jiachao Yao
- Interdisciplinary Research Academy, Zhejiang Shuren University, Hangzhou 310015, PR China
| | - Jun Chen
- Interdisciplinary Research Academy, Zhejiang Shuren University, Hangzhou 310015, PR China.
| | - Dzmitry Hrynshpan
- Research Institute of Physical and Chemical Problems, Belarusian State University, Minsk 220030, Belarus
| | - Tatsiana Savitskaya
- Research Institute of Physical and Chemical Problems, Belarusian State University, Minsk 220030, Belarus
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118
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Ward LM, Shih PM. Granick revisited: Synthesizing evolutionary and ecological evidence for the late origin of bacteriochlorophyll via ghost lineages and horizontal gene transfer. PLoS One 2021; 16:e0239248. [PMID: 33507911 PMCID: PMC7842958 DOI: 10.1371/journal.pone.0239248] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 12/29/2020] [Indexed: 11/19/2022] Open
Abstract
Photosynthesis-both oxygenic and more ancient anoxygenic forms-has fueled the bulk of primary productivity on Earth since it first evolved more than 3.4 billion years ago. However, the early evolutionary history of photosynthesis has been challenging to interpret due to the sparse, scattered distribution of metabolic pathways associated with photosynthesis, long timescales of evolution, and poor sampling of the true environmental diversity of photosynthetic bacteria. Here, we reconsider longstanding hypotheses for the evolutionary history of phototrophy by leveraging recent advances in metagenomic sequencing and phylogenetics to analyze relationships among phototrophic organisms and components of their photosynthesis pathways, including reaction centers and individual proteins and complexes involved in the multi-step synthesis of (bacterio)-chlorophyll pigments. We demonstrate that components of the photosynthetic apparatus have undergone extensive, independent histories of horizontal gene transfer. This suggests an evolutionary mode by which modular components of phototrophy are exchanged between diverse taxa in a piecemeal process that has led to biochemical innovation. We hypothesize that the evolution of extant anoxygenic photosynthetic bacteria has been spurred by ecological competition and restricted niches following the evolution of oxygenic Cyanobacteria and the accumulation of O2 in the atmosphere, leading to the relatively late evolution of bacteriochlorophyll pigments and the radiation of diverse crown group anoxygenic phototrophs. This hypothesis expands on the classic "Granick hypothesis" for the stepwise evolution of biochemical pathways, synthesizing recent expansion in our understanding of the diversity of phototrophic organisms as well as their evolving ecological context through Earth history.
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Affiliation(s)
- Lewis M. Ward
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, United States of America
| | - Patrick M. Shih
- Department of Plant Biology, University of California, Davis, California, United States of America
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- Feedstocks Division, Joint BioEnergy Institute, Emeryville, California, United States of America
- Genome Center, University of California, Davis, California, United States of America
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119
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Chen L, Huang F, Zhang C, Zhang J, Liu F, Guan X. Effects of norfloxacin on nitrate reduction and dynamic denitrifying enzymes activities in groundwater. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 273:116492. [PMID: 33493764 DOI: 10.1016/j.envpol.2021.116492] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 06/12/2023]
Abstract
The impact of antibiotics on denitrification has attracted widespread attention recently. Norfloxacin, as a representative of fluoroquinolone antibiotics, is extensively detected in groundwater. However, whether the release of norfloxacin into the groundwater poses potential risks to denitrification remains unclear. In this study, effect of norfloxacin on denitrification was investigated. The results showed that increasing norfloxacin from 0 to 100 μg/L decreased nitrate removal rate from 0.68 to 0.44 mg/L/h, but enhanced N2O emission by 177 folds. Additionally, 100 μg/L of norfloxacin decreased nitrite accumulation by 50.6%. Corresponding inhibition of norfloxacin on bacterial growth, carbon source utilization, electron transport system activity and genes expression was revealed. Furthermore, denitrifying enzyme dynamic monitoring results showed that norfloxacin inhibited nitrate reductase activity, and enhanced nitrite reductase activity to some extent in denitrification process, which was consistent with the variations of nitrate and nitrite. Meanwhile, sensitivity analysis demonstrated that nitrate reductase was more easily affected by norfloxacin than nitrite reductase. Overall, this study suggests that multiple regulation of denitrifying enzyme activity contributes to evaluating the comprehensive effects of antibiotics on groundwater denitrification.
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Affiliation(s)
- Linpeng Chen
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China; Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing), Beijing, 100083, PR China
| | - Fuyang Huang
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China; Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing), Beijing, 100083, PR China
| | - Chong Zhang
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China; Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing), Beijing, 100083, PR China
| | - Jia Zhang
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China; Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing), Beijing, 100083, PR China
| | - Fei Liu
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China; Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing), Beijing, 100083, PR China.
| | - Xiangyu Guan
- Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing), Beijing, 100083, PR China; School of Ocean Sciences, China University of Geosciences (Beijing), Beijing, 100083, PR China
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120
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Li W, Shi C, Yu Y, Ruan Y, Kong D, Lv X, Xu P, Awasthi MK, Dong M. Interrelationships between tetracyclines and nitrogen cycling processes mediated by microorganisms: A review. BIORESOURCE TECHNOLOGY 2021; 319:124036. [PMID: 33032187 DOI: 10.1016/j.biortech.2020.124036] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 08/13/2020] [Accepted: 08/15/2020] [Indexed: 06/11/2023]
Abstract
Due to their broad-spectrum antibacterial activity and low cost, tetracyclines (TCs) are a class of antibiotics widely used for human and veterinary medical purposes and as a growth-promoting agent for aquaculture. Interrelationships between TCs and nitrogen cycling have attracted scientific attention due to the complicated processes mediated by microorganisms. TCs negatively impact the nitrogen cycling; however, simultaneous degradation of TCs during nitrogen cycling mediated by microorganisms can be achieved. This review encapsulates the background and distribution of TCs in the environment. Additionally, the main nitrogen cycling process mediated by microorganisms were retrospectively examined. Furthermore, effects of TCs on the nitrogen cycling processes, namely nitrification, denitrification, and anammox, have been summarized. Finally, the pathway and microbial mechanism of degradation of TCs accompanied by nitrogen cycling processes were reviewed, along with the scope for prospective studies.
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Affiliation(s)
- Wenbing Li
- Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, China
| | - Changze Shi
- Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, China
| | - Yanwen Yu
- Zhejiang Water Healer Environmental Technology Co., Ltd, Hangzhou 311121, China
| | - Yunjie Ruan
- Institute of Agricultural Bio-Environmental Engineering, College of Bio-systems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Dedong Kong
- Agricultural Experiment Station, Zhejiang University, Hangzhou 310058, China
| | - Xiaofei Lv
- Department of Environmental Engineering, China Jiliang University, Hangzhou, China
| | - Ping Xu
- Department of Tea Science, Zhejiang University, Hangzhou 310058, China
| | - Mukesh Kumar Awasthi
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province 712100, PR China; Swedish Centre for Resource Recovery, University of Borås, 50190 Borås, Sweden.
| | - Ming Dong
- Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, China
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121
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Zhou Y, Suenaga T, Qi C, Riya S, Hosomi M, Terada A. Temperature and oxygen level determine N 2 O respiration activities of heterotrophic N 2 O-reducing bacteria: Biokinetic study. Biotechnol Bioeng 2020; 118:1330-1341. [PMID: 33305820 DOI: 10.1002/bit.27654] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 11/23/2020] [Accepted: 12/09/2020] [Indexed: 12/24/2022]
Abstract
Nitrous oxide (N2 O), a potent greenhouse gas, is reduced to N2 gas by N2 O-reducing bacteria (N2 ORB), a process which represents an N2 O sink in natural and engineered ecosystems. The N2 O sink activity by N2 ORB depends on temperature and O2 exposure, yet the specifics are not yet understood. This study explores the effects of temperature and oxygen exposure on biokinetics of pure culture N2 ORB. Four N2 ORB, representing either clade I type nosZ (Pseudomonas stutzeri JCM5965 and Paracoccus denitrificans NBRC102528) or clade II type nosZ (Azospira sp. strains I09 and I13), were individually tested. The higher activation energy for N2 O by Azospira sp. strain I13 (114.0 ± 22.6 kJ mol-1 ) compared with the other tested N2 ORB (38.3-60.1 kJ mol-1 ) indicates that N2 ORB can adapt to different temperatures. The O2 inhibition constants (KI ) of Azospira sp. strain I09 and Ps. stutzeri JCM5965 increased from 0.06 ± 0.05 and 0.05 ± 0.02 μmol L-1 to 0.92 ± 0.24 and 0.84 ± 0.31 μmol L-1 , respectively, as the temperature increased from 15°C to 35°C, while that of Azospira sp. strain I13 was temperature-independent (p = 0.106). Within the range of temperatures examined, Azospira sp. strain I13 had a faster recovery after O2 exposure compared with Azospira sp. strain I09 and Ps. stutzeri JCM5965 (p < 0.05). These results suggest that temperature and O2 exposure result in the growth of ecophysiologically distinct N2 ORB as N2 O sinks. This knowledge can help develop a suitable N2 O mitigation strategy according to the physiologies of the predominant N2 ORB.
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Affiliation(s)
- Yiwen Zhou
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Toshikazu Suenaga
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Chuang Qi
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan.,School of Environment, Nanjing Normal University, Nanjing, China
| | - Shohei Riya
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Masaaki Hosomi
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Akihiko Terada
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan.,Global Innovation Research Institute, Tokyo University of Agriculture and Technology, Tokyo, Japan
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Aerobic and anaerobic iron oxidizers together drive denitrification and carbon cycling at marine iron-rich hydrothermal vents. ISME JOURNAL 2020; 15:1271-1286. [PMID: 33328652 PMCID: PMC8114936 DOI: 10.1038/s41396-020-00849-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 11/06/2020] [Accepted: 11/18/2020] [Indexed: 12/02/2022]
Abstract
In principle, iron oxidation can fuel significant primary productivity and nutrient cycling in dark environments such as the deep sea. However, we have an extremely limited understanding of the ecology of iron-based ecosystems, and thus the linkages between iron oxidation, carbon cycling, and nitrate reduction. Here we investigate iron microbial mats from hydrothermal vents at Lōʻihi Seamount, Hawaiʻi, using genome-resolved metagenomics and metatranscriptomics to reconstruct potential microbial roles and interactions. Our results show that the aerobic iron-oxidizing Zetaproteobacteria are the primary producers, concentrated at the oxic mat surface. Their fixed carbon supports heterotrophs deeper in the mat, notably the second most abundant organism, Candidatus Ferristratum sp. (uncultivated gen. nov.) from the uncharacterized DTB120 phylum. Candidatus Ferristratum sp., described using nine high-quality metagenome-assembled genomes with similar distributions of genes, expressed nitrate reduction genes narGH and the iron oxidation gene cyc2 in situ and in response to Fe(II) in a shipboard incubation, suggesting it is an anaerobic nitrate-reducing iron oxidizer. Candidatus Ferristratum sp. lacks a full denitrification pathway, relying on Zetaproteobacteria to remove intermediates like nitrite. Thus, at Lōʻihi, anaerobic iron oxidizers coexist with and are dependent on aerobic iron oxidizers. In total, our work shows how key community members work together to connect iron oxidation with carbon and nitrogen cycling, thus driving the biogeochemistry of exported fluids.
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123
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Zhang S, Zhang Z, Xia S, Ding N, Long X, Wang J, Chen M, Ye C, Chen S. Combined genome-centric metagenomics and stable isotope probing unveils the microbial pathways of aerobic methane oxidation coupled to denitrification process under hypoxic conditions. BIORESOURCE TECHNOLOGY 2020; 318:124043. [PMID: 32911364 DOI: 10.1016/j.biortech.2020.124043] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/14/2020] [Accepted: 08/19/2020] [Indexed: 06/11/2023]
Abstract
Obligate aerobic methanotrophs have been proven to oxidize methane and participate in denitrification under hypoxic conditions. However, this phenomenon and its metabolic mechanism have not been investigated in detail in aerobic methane oxidation coupled to denitrification (AME-D) process. In this study, a type of hypoxic AME-D consortium was enriched and operated for a long time in a CH4-cycling bioreactor with strict anaerobic control and the nitrite removal rate reached approximately 50 mg N/L/d. Metagenomics combined with DNA stable-isotope probing demonstrated that the genus Methylomonas, which constitutes type I aerobic methanotrophs, was the dominant member and contributed to methane oxidation and partial denitrification. Metagenomic binning recovered a near-complete (98%) draft genome affiliated with the family Methylococcaceae containing essential genes that encode nitrite reductase (nirK), nitric oxide reductase (norBC) and hydroxylamine dehydrogenase (hao). Metabolic reconstruction of the selected Methylococcaceae genomes also revealed a potential link between methanotrophy and partial denitrification.
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Affiliation(s)
- Shici Zhang
- School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan 430070, China; Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Zhaoji Zhang
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| | - Shibin Xia
- School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan 430070, China
| | - Ningning Ding
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Xien Long
- School of Geographic Sciences, Nantong University, No. 999 Tongjing Road, Nantong 226007, China
| | - Jinsong Wang
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Minquan Chen
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Chengsong Ye
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Shaohua Chen
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
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124
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Zhang Z, Zhang Y, Chen Y. Comparative Metagenomic and Metatranscriptomic Analyses Reveal the Functional Species and Metabolic Characteristics of an Enriched Denitratation Community. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14312-14321. [PMID: 33118807 DOI: 10.1021/acs.est.0c03164] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Nitrite supply for mainstream anammox via denitratation has attracted increasing attention. The functional species responsible for denitratation and their metabolic characteristics were unravelled in this study. A highly stable denitratation community was enriched from activated sludge by combined control of C/N and pH. Nitrite accumulation and nitrate removal efficiencies were both higher than 80% during long-term operation (>100 d). The genotypic complete denitrifier Thauera aminoaromatica MZ1T was identified to be mainly responsible for acetate consumption, polyhydroxybutyrate (PHB) accumulation, and nitrate reduction. The presence of nitrate restricted the transcription and electron allocation of downstream denitrifying enzymes due to low expression of their electron transport modules (cytochrome bc1 and cytochrome c). Metabolic reconstruction of this strain indicated that the reducing power generated via the tricarboxylic acid (TCA) cycle was mainly provided for PHB synthesis and nitrate reduction in the exogenous feast phase. After the depletion of acetate, PHB was degraded and then entered the TCA cycle, providing reducing power for nitrate reduction. This allocation strategy of reducing power with priority given to carbon storage instead of nitrite reduction might favor their survival in oligotrophic and weak alkaline habitats. These results updated our understanding of the causes underlying nitrite accumulation and its physiological benefits.
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Affiliation(s)
- Zhengzhe Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, P. R. China
| | - Yu Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, P. R. China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, P. R. China
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125
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Mapping of the Denitrification Pathway in Burkholderia thailandensis by Genome-Wide Mutant Profiling. J Bacteriol 2020; 202:JB.00304-20. [PMID: 32900830 DOI: 10.1128/jb.00304-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 08/28/2020] [Indexed: 12/11/2022] Open
Abstract
Burkholderia thailandensis is a soil saprophyte that is closely related to the pathogen Burkholderia pseudomallei, the etiological agent of melioidosis in humans. The environmental niches and infection sites occupied by these bacteria are thought to contain only limited concentrations of oxygen, where they can generate energy via denitrification. However, knowledge of the underlying molecular basis of the denitrification pathway in these bacteria is scarce. In this study, we employed a transposon sequencing (Tn-Seq) approach to identify genes conferring a fitness benefit for anaerobic growth of B. thailandensis Of the 180 determinants identified, several genes were shown to be required for growth under denitrifying conditions: the nitrate reductase operon narIJHGK2K1, the aniA gene encoding a previously unknown nitrite reductase, and the petABC genes encoding a cytochrome bc 1, as well as three novel regulators that control denitrification. Our Tn-Seq data allowed us to reconstruct the entire denitrification pathway of B. thailandensis and shed light on its regulation. Analyses of growth behaviors combined with measurements of denitrification metabolites of various mutants revealed that nitrate reduction provides sufficient energy for anaerobic growth, an important finding in light of the fact that some pathogenic Burkholderia species can use nitrate as a terminal electron acceptor but are unable to complete denitrification. Finally, we demonstrated that a nitrous oxide reductase mutant is not affected for anaerobic growth but is defective in biofilm formation and accumulates N2O, which may play a role in the dispersal of B. thailandensis biofilms.IMPORTANCE Burkholderia thailandensis is a soil-dwelling saprophyte that is often used as surrogate of the closely related pathogen Burkholderia pseudomallei, the causative agent of melioidosis and a classified biowarfare agent. Both organisms are adapted to grow under oxygen-limited conditions in rice fields by generating energy through denitrification. Microoxic growth of B. pseudomallei is also considered essential for human infections. Here, we have used a Tn-Seq approach to identify the genes encoding the enzymes and regulators required for growth under denitrifying conditions. We show that a mutant that is defective in the conversion of N2O to N2, the last step in the denitrification process, is unaffected in microoxic growth but is severely impaired in biofilm formation, suggesting that N2O may play a role in biofilm dispersal. Our study identified novel targets for the development of therapeutic agents to treat meliodiosis.
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Orschler L, Agrawal S, Lackner S. Targeted metagenomics reveals extensive diversity of the denitrifying community in partial nitritation anammox and activated sludge systems. Biotechnol Bioeng 2020; 118:433-441. [PMID: 32979228 DOI: 10.1002/bit.27581] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 09/06/2020] [Accepted: 09/07/2020] [Indexed: 01/18/2023]
Abstract
The substantial presence of denitrifiers has already been reported in partial nitritation anammox (PNA) systems using the 16S ribosomal RNA (rRNA) gene, but little is known about the phylogenetic diversity based on denitrification pathway functional genes. Therefore, we performed a metagenomic analysis to determine the distribution of denitrification genes and the associated phylogeny in PNA systems and whether a niche separation between PNA and conventional activated sludge (AS) systems exists. The results revealed a distinct abundance pattern of denitrification pathway genes and their association to the microbial species between PNA and AS systems. In contrast, the taxonomic analysis, based on the 16S rRNA gene, did not detect notable variability in denitrifying community composition across samples. In general, narG and nosZa2 genes were dominant in all samples. While the potential for different stages of denitrification was redundant, variation in species composition and lack of the complete denitrification gene pool in each species appears to confer niche separation between PNA and AS systems. This study suggests that targeted metagenomics can help to determine the denitrifying microbial composition at a fine-scale resolution while overcoming current biases in quantitative polymerase chain reaction approaches due to a lack of appropriate primers.
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Affiliation(s)
- Laura Orschler
- Department of Wastewater Engineering, Institute IWAR, Technical University of Darmstadt, Darmstadt, Germany
| | - Shelesh Agrawal
- Department of Wastewater Engineering, Institute IWAR, Technical University of Darmstadt, Darmstadt, Germany
| | - Susanne Lackner
- Department of Wastewater Engineering, Institute IWAR, Technical University of Darmstadt, Darmstadt, Germany
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127
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Ruan Y, Kumar Awasthi M, Cai L, Lu H, Xu X, Li W. Simultaneous aerobic denitrification and antibiotics degradation by strain Marinobacter hydrocarbonoclasticus RAD-2. BIORESOURCE TECHNOLOGY 2020; 313:123609. [PMID: 32506034 DOI: 10.1016/j.biortech.2020.123609] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/29/2020] [Accepted: 05/30/2020] [Indexed: 06/11/2023]
Abstract
Simultaneous denitrification and antibiotics (oxytetracycline, OTC and ciprofloxacin, CFX) degradation was evaluated using a typical aerobic denitrifying strain Marinobacter hydrocarbonoclasticus RAD-2. There was no significant influence on the aerobic nitrate removal efficiency of strain RAD-2 in the presence of these two antibiotics. Along with denitrification, the average degradation rate of 2.92 μg OTC L-1h-1 was achieved, while no degradation was observed for CFX. The growth behavior indicated that an insignificant inhibition effect could have occurred at an antibiotics dosage lower than 300 μg/L. The transcriptional results revealed that antibiotics exposure caused (<2h) down-regulation of the denitrifying related genes, but triggered a significant subsequent up-regulation (4 h). Less nitrous oxide productions were observed in both aerobic and anoxic denitrification processes with antibiotics. Overall, the hormesis effect caused by antibiotics exposure indicated a potential approach to enhance the co-metabolism degradation performance for nitrate and antibiotics in aerobic denitrification.
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Affiliation(s)
- Yunjie Ruan
- Institute of Agricultural Bio-Environmental Engineering, College of Bio-systems, Engineering and Food Science, Zhejiang University, Hangzhou 310058, China; Academy of Rural Development, Zhejiang University, Hangzhou 310058, China
| | - Mukesh Kumar Awasthi
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province 712100, China; Swedish Centre for Resource Recovery, University of Borås, 50190 Borås, Sweden
| | - Lei Cai
- Laboratory of Microbial Resources, College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035, China
| | - Huifeng Lu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Xiangyang Xu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Wenbing Li
- Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, China.
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128
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Szeinbaum N, Nunn BL, Cavazos AR, Crowe SA, Stewart FJ, DiChristina TJ, Reinhard CT, Glass JB. Novel insights into the taxonomic diversity and molecular mechanisms of bacterial Mn(III) reduction. ENVIRONMENTAL MICROBIOLOGY REPORTS 2020; 12:583-593. [PMID: 32613749 PMCID: PMC7775658 DOI: 10.1111/1758-2229.12867] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 06/27/2020] [Accepted: 06/29/2020] [Indexed: 05/23/2023]
Abstract
Soluble ligand-bound Mn(III) can support anaerobic microbial respiration in diverse aquatic environments. Thus far, Mn(III) reduction has only been associated with certain Gammaproteobacteria. Here, we characterized microbial communities enriched from Mn-replete sediments of Lake Matano, Indonesia. Our results provide the first evidence for the biological reduction of soluble Mn(III) outside the Gammaproteobacteria. Metagenome assembly and binning revealed a novel betaproteobacterium, which we designate 'Candidatus Dechloromonas occultata.' This organism dominated the enrichment and expressed a porin-cytochrome c complex typically associated with iron-oxidizing Betaproteobacteria and a novel cytochrome c-rich protein cluster (Occ), including an undecaheme putatively involved in extracellular electron transfer. This occ gene cluster was also detected in diverse aquatic bacteria, including uncultivated Betaproteobacteria from the deep subsurface. These observations provide new insight into the taxonomic and functional diversity of microbially driven Mn(III) reduction in natural environments.
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Affiliation(s)
- Nadia Szeinbaum
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- NASA Astrobiology Institute, Alternative Earths Team, Mountain View, CA, USA
| | - Brook L. Nunn
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Amanda R. Cavazos
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Sean A. Crowe
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
- Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Frank J. Stewart
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
| | | | - Christopher T. Reinhard
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- NASA Astrobiology Institute, Alternative Earths Team, Mountain View, CA, USA
| | - Jennifer B. Glass
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- NASA Astrobiology Institute, Alternative Earths Team, Mountain View, CA, USA
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129
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Liu RR, Tian Y, Zhou EM, Xiong MJ, Xiao M, Li WJ. Distinct Expression of the Two NO-Forming Nitrite Reductases in Thermus antranikianii DSM 12462 T Improved Environmental Adaptability. MICROBIAL ECOLOGY 2020; 80:614-626. [PMID: 32474659 DOI: 10.1007/s00248-020-01528-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 05/14/2020] [Indexed: 05/21/2023]
Abstract
Hot spring ecosystems are analogous to some thermal environments on the early Earth and represent ideal models to understand life forms and element cycling on the early Earth. Denitrification, an important component of biogeochemical nitrogen cycle, is highly active in hot springs. Nitrite (NO2-) reduction to nitric oxide (NO) is the significant and rate-limiting pathway in denitrification and is catalyzed by two types of nitrite reductases, encoded by nirS and nirK genes. NirS and NirK were originally considered incompatible in most denitrifying organisms, although a few strains have been reported to possess both genes. Herein, we report the functional division of nirS and nirK in Thermus, a thermophilic genus widespread in thermal ecosystems. Transcriptional levels of nirS and nirK coexisting in Thermus antranikianii DSM 12462T were measured to assess the effects of nitrite, oxygen, and stimulation time. Thirty-nine Thermus strains were used to analyze the phylogeny and distribution of nirS and nirK; six representative strains were used to assess the denitrification phenotype. The results showed that both genes were actively transcribed and expressed independently in T. antranikianii DSM 12462T. Strains with both nirS and nirK had a wider range of nitrite adaptation and revealed nir-related physiological adaptations in Thermus: nirK facilitated adaptation to rapid changes and extended the adaptation range of nitrite under oxygen-limited conditions, while nirS expression was higher under oxic and relatively stable conditions.
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Affiliation(s)
- Rui-Rui Liu
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China
| | - Ye Tian
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China
| | - En-Min Zhou
- School of Resource Environment and Earth Science, Yunnan Institute of Geography, Yunnan University, Kunming, 650091, People's Republic of China
| | - Meng-Jie Xiong
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China
| | - Min Xiao
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China.
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, People's Republic of China.
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130
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Shukla S, Rajta A, Setia H, Bhatia R. Simultaneous nitrification-denitrification by phosphate accumulating microorganisms. World J Microbiol Biotechnol 2020; 36:151. [PMID: 32924078 DOI: 10.1007/s11274-020-02926-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 09/05/2020] [Indexed: 12/24/2022]
Abstract
Nitrogen and phosphorous are important inorganic water pollutants that pose a major threat to the environment and health of both humans and animals. The physical and chemical ways to remove these pollutants from water and soil are expensive and harsh, so biological removal becomes the method of choice to alleviate the problem without any side effects. The identification of microorganisms capable of simultaneous heterotrophic nitrification and aerobic denitrification has greatly simplified the sequestration of nitrogen from ammonium (NH4+) into dinitrogen (N2). Further, the discovery of phosphorous accumulating organisms offers greater economic benefits because these organisms can favourably and simultaneously remove both nitrogen and phosphorous from wastewaters hence reducing the nutrient burden. The stability of the system and removal efficiency of inorganic pollutants can be enhanced by the use of immobilized organisms. However, limited work has been done so far in this direction and there is a need to further the efforts towards refining process efficiency by testing low-cost substrates and diverse microbial populations for the total eradication of these contaminants from wastewaters.
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Affiliation(s)
- Shivani Shukla
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, 160014, India
| | - Ankita Rajta
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, 160014, India
| | - Hema Setia
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, 160014, India
| | - Ranjana Bhatia
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, 160014, India.
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131
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in 't Zandt MH, Frank J, Yilmaz P, Cremers G, Jetten MSM, Welte CU. Long-term enriched methanogenic communities from thermokarst lake sediments show species-specific responses to warming. FEMS MICROBES 2020; 1:xtaa008. [PMID: 37333957 PMCID: PMC10117432 DOI: 10.1093/femsmc/xtaa008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 10/14/2020] [Indexed: 04/05/2024] Open
Abstract
Thermokarst lakes are large potential greenhouse gas (GHG) sources in a changing Arctic. In a warming world, an increase in both organic matter availability and temperature is expected to boost methanogenesis and potentially alter the microbial community that controls GHG fluxes. These community shifts are, however, challenging to detect by resolution-limited 16S rRNA gene-based approaches. Here, we applied full metagenome sequencing on long-term thermokarst lake sediment enrichments on acetate and trimethylamine at 4°C and 10°C to unravel species-specific responses to the most likely Arctic climate change scenario. Substrate amendment was used to mimic the increased organic carbon availability upon permafrost thaw. By performing de novo assembly, we reconstructed five high-quality and five medium-quality metagenome-assembled genomes (MAGs) that represented 59% of the aligned metagenome reads. Seven bacterial MAGs belonged to anaerobic fermentative bacteria. Within the Archaea, the enrichment of methanogenic Methanosaetaceae/Methanotrichaceae under acetate amendment and Methanosarcinaceae under trimethylamine (TMA) amendment was not unexpected. Surprisingly, we observed temperature-specific methanogenic (sub)species responses with TMA amendment. These highlighted distinct and potentially functional climate-induced shifts could not be revealed with 16S rRNA gene-based analyses. Unraveling these temperature- and nutrient-controlled species-level responses is essential to better comprehend the mechanisms that underlie GHG production from Arctic lakes in a warming world.
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Affiliation(s)
- Michiel H in 't Zandt
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
- Netherlands Earth System Science Centre, Utrecht University, Heidelberglaan 2, 3584 CS Utrecht, the Netherlands
| | - Jeroen Frank
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
- Soehngen Institute of Anaerobic Microbiology, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Polen Yilmaz
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Geert Cremers
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
- Netherlands Earth System Science Centre, Utrecht University, Heidelberglaan 2, 3584 CS Utrecht, the Netherlands
- Soehngen Institute of Anaerobic Microbiology, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
| | - Cornelia U Welte
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
- Soehngen Institute of Anaerobic Microbiology, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands
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132
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Yang J, Feng L, Pi S, Cui D, Ma F, Zhao HP, Li A. A critical review of aerobic denitrification: Insights into the intracellular electron transfer. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 731:139080. [PMID: 32417477 DOI: 10.1016/j.scitotenv.2020.139080] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/04/2020] [Accepted: 04/26/2020] [Indexed: 05/23/2023]
Abstract
Aerobic denitrification is a novel biological nitrogen removal technology, which has been widely investigated as an alternative to the conventional denitrification and for its unique advantages. To fully comprehend aerobic denitrification, it is essential to clarify the regulatory mechanisms of intracellular electron transfer during aerobic denitrification. However, reports on intracellular electron transfer during aerobic denitrification are rather limited. Thus, the purpose of this review is to discuss the molecular mechanism of aerobic denitrification from the perspective of electron transfer, by summarizing the advancements in current research on electron transfer based on conventional denitrification. Firstly, the implication of aerobic denitrification is briefly discussed, and the status of current research on aerobic denitrification is summarized. Then, the occurring foundation and significance of aerobic denitrification are discussed based on a brief review of the key components involved in the electron transfer of denitrifying enzymes. Moreover, a strategy for enhancing the efficiency of aerobic denitrification is proposed on the basis of the regulatory mechanisms of denitrification enzymes. Finally, scientific outlooks are given for further investigation on aerobic denitrification in the future. This review could help clarify the mechanism of aerobic denitrification from the perspective of electron transfer.
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Affiliation(s)
- Jixian Yang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Liang Feng
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Shanshan Pi
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Di Cui
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China; Engineering Research Center for Medicine, College of Pharmacy, Harbin University of Commerce, Harbin 150076, People's Republic of China
| | - Fang Ma
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - He-Ping Zhao
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Ang Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China.
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Involvement of the cbb3-Type Terminal Oxidase in Growth Competition of Bacteria, Biofilm Formation, and in Switching between Denitrification and Aerobic Respiration. Microorganisms 2020; 8:microorganisms8081230. [PMID: 32806683 PMCID: PMC7464135 DOI: 10.3390/microorganisms8081230] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/10/2020] [Accepted: 08/10/2020] [Indexed: 11/16/2022] Open
Abstract
Paracoccus denitrificans has a branched electron transport chain with three terminal oxidases transferring electrons to molecular oxygen, namely aa3-type and cbb3-type cytochrome c oxidases and ba3-type ubiquinol oxidase. In the present study, we focused on strains expressing only one of these enzymes. The competition experiments showed that possession of cbb3-type oxidase confers significant fitness advantage during oxygen-limited growth and supports the biofilm lifestyle. The aa3-type oxidase was shown to allow rapid aerobic growth at a high oxygen supply. Activity of the denitrification pathway that had been expressed in cells grown anaerobically with nitrate was fully inhibitable by oxygen only in wild-type and cbb3 strains, while in strains aa3 and ba3 dinitrogen production from nitrate and oxygen consumption occurred simultaneously. Together, the results highlight the importance of the cbb3-type oxidase for the denitrification phenotype and suggest a way of obtaining novel bacterial strains capable of aerobic denitrification.
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134
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Xie R, Rao P, Pang Y, Shi C, Li J, Shen D. Salt intrusion alters nitrogen cycling in tidal reaches as determined in field and laboratory investigations. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 729:138803. [PMID: 32361438 DOI: 10.1016/j.scitotenv.2020.138803] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/06/2020] [Accepted: 04/17/2020] [Indexed: 06/11/2023]
Abstract
Salinization is a growing problem throughout the world and poses a threat especially to freshwater ecosystems. However, much remains to be learned about the mechanisms by which salinity impacts microbially mediated biogeochemical processes. Elevated nitrogen (N) concentrations in estuarine ecosystems have led to their eutrophication, but the relationship between N transformation and the functional genes involved in the response to saltwater intrusion is poorly understood. Here, using the Minjiang River, a tidal river in southeastern China as an easily accessible natural laboratory, we conducted a 2-year field survey to investigate N speciation during ebb and flood tides. Then, in a laboratory experiment we simulated the varying degrees of salt intrusion that occur in natural tidal reaches. The microcosm study allowed quantitative assessments of N transformation and functional gene responses. The field surveys showed that concentrations of NH4+ rose during flood tides, while the concentrations of NO3- and total N fluctuated. In the microcosms, NO3- concentrations decreased in response to salt pulses, due to simultaneous declines in the abundance of genes responsible for nitrification and increases in the abundance of those involved in dissimilatory nitrate reduction to ammonium (DNRA). The elevated salinity led to increased yields of NH4+, a response that correlated positively with the abundance of nrfA genes, involved in DNRA. Furthermore, an increase in salinity promoted N2O accumulation during the denitrification process. Altogether, our study suggests that saltwater intrusion leads to a decrease in nitrification while favoring N transformation via denitrification and DNRA and that N2O accumulation in the water is dependent on the strength of the salt pulse.
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Affiliation(s)
- Rongrong Xie
- College of Environmental Science and Engineering, Fujian Normal University, Fuzhou 350007, China; Key Laboratory of Pollution Control and Resource Recycling of Fujian Province, Fujian Normal University, Fuzhou 350007, China; Section of Physical Oceanography and Instrumentation, Leibniz Institute for Baltic Sea Research, Warnemuende, D-18119 Rostock, Germany
| | - Peiyuan Rao
- College of Environmental Science and Engineering, Fujian Normal University, Fuzhou 350007, China
| | - Yong Pang
- College of Environment, Hohai University, Nanjing 210098, China
| | - Chengchun Shi
- Fuzhou Research Academy of Environmental Sciences, Fuzhou 350013, China
| | - Jiabing Li
- College of Environmental Science and Engineering, Fujian Normal University, Fuzhou 350007, China; Key Laboratory of Pollution Control and Resource Recycling of Fujian Province, Fujian Normal University, Fuzhou 350007, China.
| | - Dandan Shen
- Section of Biological Oceanography, Leibniz Institute for Baltic Sea Research, Warnemuende, D-18119 Rostock, Germany; Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91 Stockholm, Sweden.
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135
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Ma Y, Dai W, Zheng P, Zheng X, He S, Zhao M. Iron scraps enhance simultaneous nitrogen and phosphorus removal in subsurface flow constructed wetlands. JOURNAL OF HAZARDOUS MATERIALS 2020; 395:122612. [PMID: 32361175 DOI: 10.1016/j.jhazmat.2020.122612] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 03/26/2020] [Accepted: 03/27/2020] [Indexed: 06/11/2023]
Abstract
In rural domestic wastewater treatment using subsurface constructed wetland system (SFCWs), the lack of a carbon source for denitrification and limited phosphorus uptake are responsible for low removal of nitrogen and phosphorus, and a suitable substrate is therefore, necessary. Iron is an important component in nitrogen and phosphorus biogeochemical cycles. Few studies have addressed the application of iron in SFCWs. Therefore, we constructed SFCWs that used iron scraps as a substrate. Enhanced nitrification, denitrification and removal of phosphorus were observed. The large proportion of nitrite-oxidising bacteria present in CWs with iron scraps (CW-T) compared to gravel beds indicated that iron may enhance ammonium (NH4+) oxidation. More nitrate-reducing bacteria related to Fe and autotrophic denitrifying bacteria were discovered in the back zone of CW-T and these enhanced denitrification process. Phosphate (PO43-) reacted with ferrous ion (Fe2+) and ferric ion (Fe3+) to generate the precipitant. Moreover, Fe3+ reacted with water to generate iron oxide (FeOOH) that had a large adsorption capacity for phosphorus. After six months of operation, average NH4+-N, total nitrogen and total phosphorus removal rates were 66.98 ± 13.37 %, 71.26 ± 13.57 % and 93.54 ± 6.64 %, respectively. Iron scraps can potentially be utilised in SFCWs in rural domestic wastewater treatment.
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Affiliation(s)
- Yuhui Ma
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Wanqing Dai
- School of Life and Environmental Science, Wenzhou University, Wenzhou, 325000, China
| | - Peiru Zheng
- School of Life and Environmental Science, Wenzhou University, Wenzhou, 325000, China
| | - Xiangyong Zheng
- School of Life and Environmental Science, Wenzhou University, Wenzhou, 325000, China.
| | - Shengbing He
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
| | - Min Zhao
- School of Life and Environmental Science, Wenzhou University, Wenzhou, 325000, China
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136
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Hu B, Wang Y, Quan J, Huang K, Gu X, Zhu J, Yan Y, Wu P, Yang L, Zhao J. Effects of static magnetic field on the performances of anoxic/oxic sequencing batch reactor. BIORESOURCE TECHNOLOGY 2020; 309:123299. [PMID: 32289656 DOI: 10.1016/j.biortech.2020.123299] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/29/2020] [Accepted: 03/31/2020] [Indexed: 06/11/2023]
Abstract
Two anoxic/oxic (A/O) sequencing batch reactor (SBR) processes were utilized to study the effects of static magnetic field (SMF) on biological wastewater treatment process. Except for conventional indices, the reduced nicotinamide adenine dinucleotide (NADH)/oxidized nicotinamide adenine dinucleotide (NAD+) ratio and electron transport system activity (ETSA), as well as poly-beta-hydroxybutyrate (PHB) and extracellular polymetric substance (EPS) contents in two reactors which were with and without SMF under two cyclic times (12 h and 8 h) were monitored. When the process was enhanced by SMF, the total nitrogen removal efficiency can be improved (>80%), and the NADN/NAD+ ratio, ESTA, the maximum EPS content and the maximum PHB content in the reactor with SMF were higher. Besides, SMF can reduce the microorganism community diversity and make species distribute more even and abundant. SMF can promote the performance of A/O SBR process via improving electron transport and microbial community.
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Affiliation(s)
- Bo Hu
- School of Civil Engineering, Chang' an University, Xi'an, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China.
| | - Yilin Wang
- School of Civil Engineering, Chang' an University, Xi'an, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China
| | - Jianing Quan
- School of Civil Engineering, Chang' an University, Xi'an, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China
| | - Kun Huang
- School of Civil Engineering, Chang' an University, Xi'an, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China
| | - Xin Gu
- School of Civil Engineering, Chang' an University, Xi'an, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China
| | - Jitao Zhu
- School of Civil Engineering, Chang' an University, Xi'an, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China
| | - Yi Yan
- School of Civil Engineering, Chang' an University, Xi'an, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China
| | - Pei Wu
- School of Civil Engineering, Chang' an University, Xi'an, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China
| | - Liwei Yang
- School of Civil Engineering, Chang' an University, Xi'an, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China
| | - Jianqiang Zhao
- Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; School of Water and Environment, Chang' an University, Xi'an, China; Key Laboratory of Environmental Protection & Pollution and Remediation of Water and Soil of Shaanxi Province, Xi'an, China
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137
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Ruan Y, Ma B, Cai C, Cai L, Gu J, Lu HF, Xu XY, Zhang M. Kinetic affinity index informs the divisions of nitrate flux in aerobic denitrification. BIORESOURCE TECHNOLOGY 2020; 309:123345. [PMID: 32305844 DOI: 10.1016/j.biortech.2020.123345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/01/2020] [Accepted: 04/07/2020] [Indexed: 06/11/2023]
Abstract
Aerobic denitrification is attracting increasing attention since its advantage of complete nitrogen removal in a single aerobic reactor with simplified configurations. This study investigated the nitrate kinetic affinity (half-saturation index, Km) by an isolated aerobic denitrifier named P. balearica strain RAD-17. It turned out that strain RAD-17 had a high Km of 162.5 mg-N/L and maximum nitrate reduction rate of 21.7 mg-N/(L•h), enabling it to treat high-strength nitrogen wastewater with high efficiency. Further analysis illustrated that Km was the critical value for the change of growth yield rate along initial nitrate concentrations. Nitrogen balance results elucidated an opposite nitrogen flux to cell synthesis and nitrogen loss during aerobic denitrification. Moreover, the expression of functional genes provided proofs for these phenotypic results at transcriptional level. Consequently, Km could be an indicator for nitrate flux division directing to respiration and assimilation in aerobic denitrifiers, shedding light on its regulation for wastewater treatment.
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Affiliation(s)
- Yunjie Ruan
- Institute of Agricultural Bio-Environmental Engineering, College of Bio-Systems Engineering and Food Science, Zhejiang University, Hangzhou 310058, PR China; The Rural Development Academy, Zhejiang University, Hangzhou 310058, PR China
| | - Bin Ma
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Chen Cai
- Advanced Water Management Centre, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Lei Cai
- Laboratory of Microbial Resources, College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035, China
| | - Jun Gu
- Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, Singapore, Singapore
| | - Hui-Feng Lu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Xiang-Yang Xu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Meng Zhang
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China; Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, Singapore, Singapore.
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138
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Jiang M, Feng L, Zheng X, Chen Y. Bio-denitrification performance enhanced by graphene-facilitated iron acquisition. WATER RESEARCH 2020; 180:115916. [PMID: 32438140 DOI: 10.1016/j.watres.2020.115916] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/21/2020] [Accepted: 05/03/2020] [Indexed: 06/11/2023]
Abstract
Bio-denitrification is widely used for remediation of nitrate contaminated site or removal of nitrate from wastewater, but its efficiency is not always satisfied and high nitrite accumulation and nitrous oxide emission occur frequently. Iron plays an important role in achieving efficient biological denitrification. Nevertheless, its concentration in cells is usually inadequate, and additional supply of iron to denitrification system has been adopted in the literature. In this study, a novel approach to increase the intracellular iron concentration of denitrifying microbes by using graphene to accelerate iron transport, which significantly enhanced bio-denitrification and decreased intermediates accumulations, was reported, and the underlying mechanisms were explored. The presence of 50 mg/L of graphene was observed to not only significantly promote nitrate removal efficiency by 67.3%, but also decrease nitrite and nitrous oxide generation by 49.0% and 63.9%, respectively. It was found that graphene promoted the generation, transfer and consumption of electrons, increased the activities or gene expressions of Fe-containing enzymes (such as complex I, complex III, various cytochromes, and most denitrification reductases), and enhanced the growth of denitrifiers due to iron acquisition by denitrifying bacteria being remarkably facilitated, leading to a significant increment of intracellular iron concentration. Meanwhile, the intracellular proton-motive force and ATP levels were promoted as well. This study provided a new approach to enhancing bio-denitrification and revealed a novel insight into biological iron acquisition.
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Affiliation(s)
- Meng Jiang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China.
| | - Leiyu Feng
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
| | - Xiong Zheng
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China.
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139
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Chen S, Li S, Huang T, Yang S, Liu K, Ma B, Shi Y, Miao Y. Nitrate reduction by Paracoccus thiophilus strain LSL 251 under aerobic condition: Performance and intracellular central carbon flux pathways. BIORESOURCE TECHNOLOGY 2020; 308:123301. [PMID: 32299051 DOI: 10.1016/j.biortech.2020.123301] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 03/29/2020] [Accepted: 03/31/2020] [Indexed: 06/11/2023]
Abstract
The intracellular carbon metabolic flux pathways of denitrifying bacteria under aerobic conditions remain unclear. Here, a newly strain LSL251 was identified as Paracoccus thiophilus. Strain LSL251 removed 94.79% and 98.78% of total organic carbon and nitrate. 74.66% of nitrogen in culture system was lost as gaseous nitrogen. Moreover, 13C stable isotopic labeling and metabolic flux analyses revealed that the primary intracellular carbon metabolic pathways were the Entner-Doudoroff pathway and the tricarboxylic acid (TCA) cycle. Electrons are primarily donated as direct electron donor-NADH through the TCA cycle. Furthermore, response surface methodology modeled that the highest total nitrogen removal efficiency was 98.43%, where the optimal parameters were C/N ratio of 8.00, 32.98 °C, 50.18 rpm, and initial pH of 7.73. All together, these results have shed new lights on intracellular central carbon metabolic distribution and flux pathways of aerobic denitrifying bacteria.
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Affiliation(s)
- Shengnan Chen
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Municipal and Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Sulin Li
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Municipal and Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Tinglin Huang
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Municipal and Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Shangye Yang
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Municipal and Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Kaiwen Liu
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Municipal and Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Ben Ma
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Municipal and Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yinjie Shi
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Municipal and Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yutian Miao
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Municipal and Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
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140
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Zhang H, Li S, Ma B, Huang T, Qiu H, Zhao Z, Huang X, Liu K. Nitrate removal characteristics and 13C metabolic pathways of aerobic denitrifying bacterium Paracoccus denitrificans Z195. BIORESOURCE TECHNOLOGY 2020; 307:123230. [PMID: 32222687 DOI: 10.1016/j.biortech.2020.123230] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/17/2020] [Accepted: 03/19/2020] [Indexed: 06/10/2023]
Abstract
Strain Z195 was isolated and identified as Paracoccus denitrificans. Z195 exhibited efficient aerobic denitrification and carbon removal abilities, and removed 93.74% of total nitrogen (TN) and 97.81% of total organic carbon.71.88% of nitrogen was lost as gaseous products.13C-metabolic flux analysis revealed that 95% and 132% of the carbon fluxes entered the Entner-Doudoroff (ED) pathway and tricarboxylic acid (TCA) cycle, respectively. Electrons produced by carbon metabolism markedly promoted the processes of nitrogen metabolism process and aerobic respiration. A response surface methodology model demonstrated that the optimal conditions for the maximum TN removal were a C/N ratio of 7.47, shaking speed of 108 rpm, temperature of 31 °C and initial pH of 8.02. Additionally, the average TN and chemical oxygen demand removal efficiencies of raw wastewater were 89% and 91%, respectively. The results give new insight for understanding metabolic flux analysis of aerobic denitrifying bacteria.
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Affiliation(s)
- Haihan Zhang
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Sulin Li
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Ben Ma
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Tinglin Huang
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Hui Qiu
- Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Zhenfang Zhao
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Xin Huang
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Kaiwen Liu
- Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China
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141
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Nitrifying and Denitrifying Microbial Communities in Centralized and Decentralized Biological Nitrogen Removing Wastewater Treatment Systems. WATER 2020. [DOI: 10.3390/w12061688] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Biological nitrogen removal (BNR) in centralized and decentralized wastewater treatment systems is assumed to be driven by the same microbial processes and to have communities with a similar composition and structure. There is, however, little information to support these assumptions, which may impact the effectiveness of decentralized systems. We used high-throughput sequencing to compare the structure and composition of the nitrifying and denitrifying bacterial communities of nine onsite wastewater treatment systems (OWTS) and one wastewater treatment plant (WTP) by targeting the genes coding for ammonia monooxygenase (amoA) and nitrous oxide reductase (nosZ). The amoA diversity was similar between the WTP and OWTS, but nosZ diversity was generally higher for the WTP. Beta diversity analyses showed the WTP and OWTS promoted distinct amoA and nosZ communities, although there is a core group of N-transforming bacteria common across scales of BNR treatment. Our results suggest that advanced N-removal OWTS have microbial communities that are sufficiently distinct from those of WTP with BNR, which may warrant different management approaches.
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142
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Stein LY. The Long-Term Relationship between Microbial Metabolism and Greenhouse Gases. Trends Microbiol 2020; 28:500-511. [DOI: 10.1016/j.tim.2020.01.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/09/2020] [Accepted: 01/16/2020] [Indexed: 11/26/2022]
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143
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Moghaddam AZ, Jazi ME, Allahrasani A, Khazaei M, Ganjali MR, Saeb MR, Vatanpour V. Removal of Chromate and Nitrate Ions from Aqueous Solutions by Co
x
Fe
3‐
x
O
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@silica Hybrid Nanoparticles Decorated with Cross‐Linked Tragacanth Gum: Experiment, Modeling and Optimization. ChemistrySelect 2020. [DOI: 10.1002/slct.202000725] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Mehdi Erfani Jazi
- Department of ChemistryMississippi State University Mississippi State Mississippi 39762 United States
| | - Ali Allahrasani
- Department of ChemistryCollege of SciencesUniversity of Birjand Birjand 97175-615 Iran
| | - Mohammad Khazaei
- Department of Environmental Health EngineeringSchool of Public Health and Research Center for Health SciencesHamadan University of Medical Sciences Hamadan Iran
| | - Mohammad Reza Ganjali
- Center of Excellence in ElectrochemistrySchool of ChemistryCollege of ScienceUniversity of Tehran Tehran Iran
- Biosensor Research CenterEndocrinology and Metabolism Molecular-Cellular Sciences InstituteTehran University of Medical Sciences Tehran Iran
| | - Mohammad Reza Saeb
- Department of Resin and AdditivesInstitute for Color Science and Technology P.O. Box 16765-654 Tehran Iran
| | - Vahid Vatanpour
- Department of Applied ChemistryFaculty of ChemistryKharazmi University P.O. Box 15719-14911 Tehran Iran
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144
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Zhao B, Dan Q, Guo LJ, An Q, Guo JS. Characterization of an aerobic denitrifier Enterobacter cloacae strain HNR and its nitrate reductase gene. Arch Microbiol 2020; 202:1775-1784. [DOI: 10.1007/s00203-020-01887-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/14/2020] [Accepted: 04/11/2020] [Indexed: 12/20/2022]
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145
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Navada S, Knutsen MF, Bakke I, Vadstein O. Nitrifying biofilms deprived of organic carbon show higher functional resilience to increases in carbon supply. Sci Rep 2020; 10:7121. [PMID: 32346018 PMCID: PMC7189377 DOI: 10.1038/s41598-020-64027-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 04/08/2020] [Indexed: 11/09/2022] Open
Abstract
In nitrifying biofilms, the organic carbon to ammonia nitrogen (C/N) supply ratio can influence resource competition between heterotrophic and nitrifying bacteria for oxygen and space. We investigated the impact of acute and chronic changes in carbon supply on inter-guild competition in two moving bed biofilm reactors (MBBR), operated with (R1) and without (R0) external organic carbon supply. The microbial and nitrifying community composition of the reactors differed significantly. Interestingly, acute increases in the dissolved organic carbon inhibited nitrification in R1 ten times more than in R0. A sustained increase in the carbon supply decreased nitrification efficiency and increased denitrification activity to a greater extent in R1, and also increased the proportion of potential denitrifiers in both bioreactors. The findings suggest that autotrophic biofilms subjected to increases in carbon supply show higher nitrification and lower denitrification activity than carbon-fed biofilms. This has significant implications for the design of nitrifying bioreactors. Specifically, efficient removal of organic matter before the nitrification unit can improve the robustness of the bioreactor to varying influent quality. Thus, maintaining a low C/N ratio is important in nitrifying biofilters when acute carbon stress is expected or when anoxic activity (e.g. denitrification or H2S production) is undesirable, such as in recirculating aquaculture systems (RAS).
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Affiliation(s)
- Sharada Navada
- Department of Chemistry, NTNU - Norwegian University of Science and Technology, N-7491, Trondheim, Norway. .,Krüger Kaldnes AS (Veolia Water Technologies), N-3241, Sandefjord, Norway.
| | - Maja F Knutsen
- Department of Biotechnology and Food Science, NTNU - Norwegian University of Science and Technology, N-7491, Trondheim, Norway.,Oxy Solutions, Gaustadalleen 21, N-0349, Oslo, Norway
| | - Ingrid Bakke
- Department of Biotechnology and Food Science, NTNU - Norwegian University of Science and Technology, N-7491, Trondheim, Norway
| | - Olav Vadstein
- Department of Biotechnology and Food Science, NTNU - Norwegian University of Science and Technology, N-7491, Trondheim, Norway
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Torregrosa-Crespo J, Pire C, Bergaust L, Martínez-Espinosa RM. Haloferax mediterranei, an Archaeal Model for Denitrification in Saline Systems, Characterized Through Integrated Physiological and Transcriptional Analyses. Front Microbiol 2020; 11:768. [PMID: 32390995 PMCID: PMC7188791 DOI: 10.3389/fmicb.2020.00768] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 03/31/2020] [Indexed: 11/13/2022] Open
Abstract
Haloferax mediterranei (R4) belongs to the group of halophilic archaea, one of the predominant microbial populations in hypersaline environments. In these ecosystems, the low availability of oxygen pushes the microbial inhabitants toward anaerobic pathways and the presence of N-oxyanions favor denitrification. In a recent study comparing three Haloferax species carrying dissimilatory N-oxide reductases, H. mediterranei showed promise as a future model for archaeal denitrification. This work further explores the respiratory physiology of this haloarchaeon when challenged with ranges of nitrite and nitrate concentrations and at neutral or sub-neutral pH during the transition to anoxia. Moreover, to begin to understand the transcriptional regulation of N-oxide reductases, detailed gas kinetics was combined with gene expression analyses at high resolution. The results show that H. mediterranei has an expression pattern similar to that observed in the bacterial Domain, well-coordinated at low concentrations of N-oxyanions. However, it could only sustain a few generations of exponential anaerobic growth, apparently requiring micro-oxic conditions for de novo synthesis of denitrification enzymes. This is the first integrated study within this field of knowledge in haloarchaea and Archaea in general, and it sheds lights on denitrification in salty environments.
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Affiliation(s)
- Javier Torregrosa-Crespo
- Department of Agrochemistry and Biochemistry, Faculty of Science, University of Alicante, Alicante, Spain
| | - Carmen Pire
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Linda Bergaust
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
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147
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Wu L, Peng L, Wei W, Wang D, Ni BJ. Nitrous oxide production from wastewater treatment: The potential as energy resource rather than potent greenhouse gas. JOURNAL OF HAZARDOUS MATERIALS 2020; 387:121694. [PMID: 31776086 DOI: 10.1016/j.jhazmat.2019.121694] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 11/13/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
Nitrous oxide (N2O), produced from wastewater treatment, is a potent greenhouse gas and has become a global concern in recent years. However, N2O has also been commonly used as a powerful oxidant for energy generation. As such, an increasing effort has been devoted to explore the energy potential of N2O from wastewater treatment processes recently. Nevertheless, the holistic knowledge on energy recovery from nitrogen in wastewater is still lacking for facilitating its further development. Striving for sustainable wastewater treatment, this review paper aimed to give the up-to-date status on several essential aspects regarding the N2O recovery as an energy resource rather than emission as a greenhouse gas, including energy production via N2O decomposition, main biotic N2O production sources, the potential bioprocesses used for N2O recovery, and the possible N2O harvesting strategies. We then put forward perspectives for N2O recovery and future challenges to improve our understanding of the energy generation, microbial processes involved and harvesting approaches in order to potentially achieve sustainable wastewater treatment via N2O recovery.
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Affiliation(s)
- Lan Wu
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Lai Peng
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
| | - Dongbo Wang
- Key Laboratory of Environmental Biology and Pollution Control, College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
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148
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Chen M, Zhou X, Chen X, Cai Q, Zeng RJ, Zhou S. Mechanisms of nitrous oxide emission during photoelectrotrophic denitrification by self-photosensitized Thiobacillus denitrificans. WATER RESEARCH 2020; 172:115501. [PMID: 31954933 DOI: 10.1016/j.watres.2020.115501] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/31/2019] [Accepted: 01/10/2020] [Indexed: 06/10/2023]
Abstract
Photoelectrotrophic denitrification (PEDeN) using bio-hybrids has the potential to remove nitrate (NO3-) from wastewater in an economical and sustainable way. As a gas of global concern, the mechanisms of nitrous oxide (N2O) emissions during this novel process remain unclear. Herein, a self-photosensitized bio-hybrid, i. e., Thiobacillus denitrificans-cadmium sulfide, was constructed and the factors affecting N2O emissions during PEDeN by the bio-hybrids were investigated. The system was sensitive to the input NO3--N and NO2--N, resulting in changes in the N2O/(N2+N2O) ratio from 1% to 95%. In addition to free nitrous acid (FNA), reactive oxidative species (ROS) were a unique factor affecting N2O emission during PEDeN. Importantly, the N2O reduction step exhibited greater susceptibility to the ROS than nitrate reduction step. The contributions of hydrogen peroxide (H2O2), superoxides (O2-•), hydroxyl radicals (•OH) and FNA to the inhibition of N2O reduction were >15.0%, >5.4%, 1.3%, and <70.2%, respectively for a reduction of 13.5 mg/L NO3--N. A significant down-regulation of the relative transcription of the gene nosZ demonstrated that the inhibition of N2O reductase occurred at the gene level. This finding has important implications not only for mitigating N2O emissions during the PEDeN process but also for encouraging a reexamination process of N2O emissions in nature, particularly in systems in which ROS are present during the denitrification process.
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Affiliation(s)
- Man Chen
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Xiaofang Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Xiangyu Chen
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Quanhua Cai
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Raymond Jianxiong Zeng
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.
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149
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Zhao S, Su X, Wang Y, Yang X, Bi M, He Q, Chen Y. Copper oxide nanoparticles inhibited denitrifying enzymes and electron transport system activities to influence soil denitrification and N 2O emission. CHEMOSPHERE 2020; 245:125394. [PMID: 31862554 DOI: 10.1016/j.chemosphere.2019.125394] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 11/09/2019] [Accepted: 11/16/2019] [Indexed: 06/10/2023]
Abstract
Nanopesticides are widely applied in modern agricultural systems to replace traditional pesticides, which inevitably leads to their accumulation in soils. Nanopesticides based on copper oxide nanoparticles (CuO NPs) may affect the soil nitrogen cycle, such as the denitrification process; however, the mechanism remains unclear. Here, acute exposure experiments for 60 h were conducted to explore the effects of CuO NPs (10, 100, 500 mg kg-1) on denitrification. In this study, Cu speciation, activities of denitrifying enzymes, electron transport system activity (ETSA), expression of denitrifying functional genes, composition of bacterial communities and reactive oxygen species (ROS) were determined. In all treatments, Cu ions was the dominant form and responsible for the toxicity of CuO NPs. The results indicated that CuO NPs treatments at 500 mg kg-1 remarkably inhibited denitrification, led to an 11-fold increase in NO3- accumulation and N2O emission rates decrease by 10.2-24.1%. In the denitrification process, the activities of nitrate reductase and nitric oxide reductase reduced by 21.1-42.1% and 10.3-16.3%, respectively, which may be a reason for the negative effect of CuO NPs. In addition, ETSA was significantly inhibited with CuO NPs applications, which reflects the ability of denitrification to accept electrons. Denitrifying functional genes and bacterial communities composition were changed, thus further influencing the denitrification process. ROS analysis showed that there were no significant differences among NPs treatments. This research improves the understanding of CuO NPs impact on soil denitrification. Further attention should be paid to the nitrogen transformation in agricultural soils in the presence of nanopesticides.
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Affiliation(s)
- Shuyuan Zhao
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Xiaoxuan Su
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Yiyu Wang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Xiangyu Yang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Mohan Bi
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Qiang He
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Yi Chen
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China.
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150
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Contextual Flexibility in Pseudomonas aeruginosa Central Carbon Metabolism during Growth in Single Carbon Sources. mBio 2020; 11:mBio.02684-19. [PMID: 32184246 PMCID: PMC7078475 DOI: 10.1128/mbio.02684-19] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen that is well known for causing infections in the airways of people with cystic fibrosis. Although it is clear that P. aeruginosa is metabolically well adapted to life in the CF lung, little is currently known about how the organism metabolizes the nutrients available in the airways. In this work, we used a combination of gene expression and isotope tracer (“fluxomic”) analyses to find out exactly where the input carbon goes during growth on two CF-relevant carbon sources, acetate and glycerol (derived from the breakdown of lung surfactant). We found that carbon is routed (“fluxed”) through very different pathways during growth on these substrates and that this is accompanied by an unexpected remodeling of the cell’s electron transfer pathways. Having access to this “blueprint” is important because the metabolism of P. aeruginosa is increasingly being recognized as a target for the development of much-needed antimicrobial agents. Pseudomonas aeruginosa is an opportunistic human pathogen, particularly noted for causing infections in the lungs of people with cystic fibrosis (CF). Previous studies have shown that the gene expression profile of P. aeruginosa appears to converge toward a common metabolic program as the organism adapts to the CF airway environment. However, we still have only a limited understanding of how these transcriptional changes impact metabolic flux at the systems level. To address this, we analyzed the transcriptome, proteome, and fluxome of P. aeruginosa grown on glycerol or acetate. These carbon sources were chosen because they are the primary breakdown products of an airway surfactant, phosphatidylcholine, which is known to be a major carbon source for P. aeruginosa in CF airways. We show that the fluxes of carbon throughout central metabolism are radically different among carbon sources. For example, the newly recognized “EDEMP cycle” (which incorporates elements of the Entner-Doudoroff [ED] pathway, the Embden-Meyerhof-Parnas [EMP] pathway, and the pentose phosphate [PP] pathway) plays an important role in supplying NADPH during growth on glycerol. In contrast, the EDEMP cycle is attenuated during growth on acetate, and instead, NADPH is primarily supplied by the reaction catalyzed by isocitrate dehydrogenase(s). Perhaps more importantly, our proteomic and transcriptomic analyses revealed a global remodeling of gene expression during growth on the different carbon sources, with unanticipated impacts on aerobic denitrification, electron transport chain architecture, and the redox economy of the cell. Collectively, these data highlight the remarkable metabolic plasticity of P. aeruginosa; that plasticity allows the organism to seamlessly segue between different carbon sources, maximizing the energetic yield from each.
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