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Min H, O'Loughlin EJ, Kwon MJ. Anaerobic microbial metabolism in soil columns affected by highly alkaline pH: Implication for biogeochemistry near construction and demolition waste disposal sites. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 368:122127. [PMID: 39128342 DOI: 10.1016/j.jenvman.2024.122127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 05/29/2024] [Accepted: 08/04/2024] [Indexed: 08/13/2024]
Abstract
Construction and demolition wastes (CDWs) have become a significant environmental concern due to urbanization. CDWs in landfill sites can generate high-pH leachate and various constituents (e.g., acetate and sulfate) following the dissolution of cement material, which may affect subsurface biogeochemical properties. However, the impact of CDW leachate on microbial reactions and community compositions in subsurface environments remains unclear. Therefore, we created columns composed of layers of concrete debris containing-soil (CDS) and underlying CDW-free soil, and fed them artificial groundwater with or without acetate and/or sulfate. In all columns, the initial pH 5.6 of the underlying soil layer rapidly increased to 10.8 (without acetate and sulfate), 10.1 (with sulfate), 10.1 (with acetate), and 8.3 (with acetate and sulfate) within 35 days. Alkaliphilic or alkaline-resistant microbes including Hydrogenophaga, Silanimonas, Algoriphagus, and/or Dethiobacter were dominant throughout the incubation in all columns, and their relative abundance was highest in the column without acetate and sulfate (50.7-86.6%). Fe(III) and sulfate reduction did not occur in the underlying soil layer without acetate. However, in the column with acetate alone, pH was decreased to 9.9 after day 85 and Fe(II) was produced with an increase in the relative abundance of Fe(III)-reducing bacteria up to 9.1%, followed by an increase in the methanogenic archaea Methanosarcina, suggestive of methanogenesis. In the column with both acetate and sulfate, Fe(III) and sulfate reduction occurred along with an increase in both Fe(III)- and sulfate-reducing bacteria (19.1 and 17.7%, respectively), while Methanosarcina appeared later. The results demonstrate that microbial Fe(III)- and sulfate-reduction and acetoclastic methanogenesis can occur even in soils with highly alkaline pH resulting from the dissolution of concrete debris.
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Affiliation(s)
- Haeun Min
- Department of Earth and Environmental Sciences, Korea University, Seoul, South Korea
| | | | - Man Jae Kwon
- Department of Earth and Environmental Sciences, Korea University, Seoul, South Korea.
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2
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Ren WT, Lv Y, He ZL, Wang HZ, Deng L, Ye SS, Wu QL, Guo WQ. Feedback of chain elongation microorganisms on iron-based conductive materials: Enhanced microbial functions and biotoxicity adaptation mechanisms. BIORESOURCE TECHNOLOGY 2024; 406:130959. [PMID: 38876286 DOI: 10.1016/j.biortech.2024.130959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 05/28/2024] [Accepted: 06/11/2024] [Indexed: 06/16/2024]
Abstract
Despite the increased research efforts aimed at understanding iron-based conductive materials (CMs) for facilitating chain elongation (CE) to produce medium chain fatty acids (MCFAs), the impact of these materials on microbial community functions and the adaptation mechanisms to their biotoxicity remain unclear. This study found that the supply of zero-valent iron (ZVI) and magnetite enhanced the MCFAs carbon-flow distribution by 26 % and 52 %, respectively. Metagenomic analysis revealed the upregulation of fatty acid metabolism, pyruvate metabolism and ABC transporters with ZVI and magnetite. The predominant functional microorganisms were Massilibacterium and Tidjanibacter with ZVI, and were Petrimonas and Candidatus_Microthrix with magnetite. Furthermore, it was demonstrated that CE microorganisms respond and adapt to the biotoxicity of iron-based CMs by adjusting Two-component system and Quorum sensing for the first time. In summary, this study provided a new deep-insight on the feedback mechanisms of CE microorganisms on iron-based CMs.
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Affiliation(s)
- Wei-Tong Ren
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Yang Lv
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Zi-Lin He
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Hua-Zhe Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Lin Deng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shan-Shan Ye
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Qing-Lian Wu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Wan-Qian Guo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
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Gafni A, Rubin-Blum M, Murrell C, Vigderovich H, Eckert W, Larke-Mejía N, Sivan O. Survival strategies of aerobic methanotrophs under hypoxia in methanogenic lake sediments. ENVIRONMENTAL MICROBIOME 2024; 19:44. [PMID: 38956741 PMCID: PMC11218250 DOI: 10.1186/s40793-024-00586-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 06/23/2024] [Indexed: 07/04/2024]
Abstract
BACKGROUND Microbial methane oxidation, methanotrophy, plays a crucial role in mitigating the release of the potent greenhouse gas methane from aquatic systems. While aerobic methanotrophy is a well-established process in oxygen-rich environments, emerging evidence suggests their activity in hypoxic conditions. However, the adaptability of these methanotrophs to such environments has remained poorly understood. Here, we explored the genetic adaptability of aerobic methanotrophs to hypoxia in the methanogenic sediments of Lake Kinneret (LK). These LK methanogenic sediments, situated below the oxidic and sulfidic zones, were previously characterized by methane oxidation coupled with iron reduction via the involvement of aerobic methanotrophs. RESULTS In order to explore the adaptation of the methanotrophs to hypoxia, we conducted two experiments using LK sediments as inoculum: (i) an aerobic "classical" methanotrophic enrichment with ambient air employing DNA stable isotope probing (DNA-SIP) and (ii) hypoxic methanotrophic enrichment with repeated spiking of 1% oxygen. Analysis of 16S rRNA gene amplicons revealed the enrichment of Methylococcales methanotrophs, being up to a third of the enriched community. Methylobacter, Methylogaea, and Methylomonas were prominent in the aerobic experiment, while hypoxic conditions enriched primarily Methylomonas. Using metagenomics sequencing of DNA extracted from these experiments, we curated five Methylococcales metagenome-assembled genomes (MAGs) and evaluated the genetic basis for their survival in hypoxic environments. A comparative analysis with an additional 62 Methylococcales genomes from various environments highlighted several core genetic adaptations to hypoxia found in most examined Methylococcales genomes, including high-affinity cytochrome oxidases, oxygen-binding proteins, fermentation-based methane oxidation, motility, and glycogen use. We also found that some Methylococcales, including LK Methylococcales, may denitrify, while metals and humic substances may also serve as electron acceptors alternative to oxygen. Outer membrane multi-heme cytochromes and riboflavin were identified as potential mediators for the utilization of metals and humic material. These diverse mechanisms suggest the ability of methanotrophs to thrive in ecological niches previously thought inhospitable for their growth. CONCLUSIONS Our study sheds light on the ability of enriched Methylococcales methanotrophs from methanogenic LK sediments to survive under hypoxia. Genomic analysis revealed a spectrum of genetic capabilities, potentially enabling these methanotrophs to function. The identified mechanisms, such as those enabling the use of alternative electron acceptors, expand our understanding of methanotroph resilience in diverse ecological settings. These findings contribute to the broader knowledge of microbial methane oxidation and have implications for understanding and potential contribution methanotrophs may have in mitigating methane emissions in various environmental conditions.
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Affiliation(s)
- Almog Gafni
- Department of Earth and Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.
| | - Maxim Rubin-Blum
- Israel Limnology and Oceanography Research, Tel Shikmona, Haifa, Israel
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Colin Murrell
- School of Environmental Sciences, University of East Anglia, Norwich, UK
| | - Hanni Vigderovich
- Department of Earth and Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Werner Eckert
- The Yigal Allon Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, Israel
| | | | - Orit Sivan
- Department of Earth and Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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Valero A, Petrash DA, Kuchenbuch A, Korth B. Enriching electroactive microorganisms from ferruginous lake waters - Mind the sulfate reducers! Bioelectrochemistry 2024; 157:108661. [PMID: 38340618 DOI: 10.1016/j.bioelechem.2024.108661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 01/23/2024] [Accepted: 01/27/2024] [Indexed: 02/12/2024]
Abstract
Electroactive microorganisms are pivotal players in mineral transformation within redox interfaces characterized by pronounced oxygen and dissolved metal gradients. Yet, their systematic cultivation from such environments remains elusive. Here, we conducted an anodic enrichment using anoxic ferruginous waters from a post-mining lake as inoculum. Weak electrogenicity (j = ∼5 µA cm-2) depended on electroactive planktonic cells rather than anodic biofilms, with a preference for formate as electron donor. Addition of yeast extract decreased the lag phase but did not increase current densities. The enriched bacterial community varied depending on the substrate composition but mainly comprised of sulfate- and nitrate-reducing bacteria (e.g., Desulfatomaculum spp. and Stenotrophomonas spp.). A secondary enrichment strategy resulted in different bacterial communities composed of iron-reducing (e.g., Klebsiella spp.) and fermentative bacteria (e.g., Paeniclostridium spp.). Secondary electron microscopy and energy-dispersive X-ray spectroscopy results indicate the precipitation of sulfur- and iron-rich organomineral aggregates at the anode surface, presumably impeding current production. Our findings indicate that (i) anoxic waters containing geogenically derived metals can be used to enrich weak electricigens, and (ii) it is necessary to specifically inhibit sulfate reducers. Otherwise, sulfate reducers tend to dominate over EAM during cultivation, which can lead to anode passivation due to biomineralization.
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Affiliation(s)
- Astolfo Valero
- Institute of Soil Biology and Biogeochemistry, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic; Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Daniel A Petrash
- Institute of Soil Biology and Biogeochemistry, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic; Department of Environmental Geochemistry and Biogeochemistry, Czech Geological Survey, Prague, Czech Republic
| | - Anne Kuchenbuch
- Department of Microbial Biotechnology, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany
| | - Benjamin Korth
- Department of Microbial Biotechnology, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany.
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Xu Y, Deng MY, Li SJ, Yuan YC, Sun HY, Wang Q, Chen RP, Yu L. Enhancing biohydrogen production from xylose through natural FeS 2 ore: Mechanistic insights. BIORESOURCE TECHNOLOGY 2024; 399:130632. [PMID: 38552859 DOI: 10.1016/j.biortech.2024.130632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 02/13/2024] [Accepted: 03/24/2024] [Indexed: 04/01/2024]
Abstract
In this study, we investigated the advantages of utilizing natural FeS2 ore in the context of dark fermentative hydrogen production within a fermentation system employing heat-treated anaerobic granular sludge with xylose as the carbon source. The results demonstrated a significant improvement in both hydrogen production and the maximum rate, with increases of 2.58 and 4.2 times, respectively. Moreover, the presence of FeS2 ore led to a reduction in lag time by more than 2-3 h. The enhanced biohydrogen production performance was attributed to factors such as the intracellular NADH/NAD+ ratio, redox-active components of extracellular polymeric substances, secreted flavins, as well as the presence of hydrogenase and nitrogenase. Furthermore, the FeS2 ore served as a direct electron donor and acceptor during biohydrogen production. This study shed light on the underlying mechanisms contributing to the improved performance of biohydrogen production from xylose during dark fermentation through the supplementation of natural FeS2 ore.
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Affiliation(s)
- Yun Xu
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Miao-Yu Deng
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Si-Jia Li
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Yi-Cheng Yuan
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Hao-Yu Sun
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Quan Wang
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Rong-Ping Chen
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Lei Yu
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China.
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6
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Eshun LE, Coker VS, Shaw S, Lloyd JR. Strategies for optimizing biovivianite production using dissimilatory Fe(III)-reducing bacteria. ENVIRONMENTAL RESEARCH 2024; 242:117667. [PMID: 37980994 DOI: 10.1016/j.envres.2023.117667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/06/2023] [Accepted: 11/13/2023] [Indexed: 11/21/2023]
Abstract
Vivianite (Fe3(PO4)2·8H2O), a sink for phosphorus, is a key mineralization product formed during the microbial reduction of phosphate-containing Fe(III) minerals in natural systems, and also in wastewater treatment where Fe(III)-minerals are used to remove phosphate. As biovivianite is a potentially useful Fe and P fertiliser, there is much interest in harnessing microbial biovivianite synthesis for circular economy applications. In this study, we investigated the factors that influence the formation of microbially-synthesized vivianite (biovivianite) under laboratory batch systems including the presence and absence of phosphate and electron shuttle, the buffer system, pH, and the type of Fe(III)-reducing bacteria (comparing Geobacter sulfurreducens and Shewanella putrefaciens). The rate of Fe(II) production, and its interactions with the residual Fe(III) and other oxyanions (e.g., phosphate and carbonate) were the main factors that controlled the rate and extent of biovivianite formation. Higher concentrations of phosphate (e.g., P/Fe = 1) in the presence of an electron shuttle, at an initial pH between 6 and 7, were needed for optimal biovivianite formation. Green rust, a key intermediate in biovivianite production, could be detected as an endpoint alongside vivianite and metavivianite (Fe2+Fe3+2(PO4)2.(OH)2.6H2O), in treatments with G. sulfurreducens and S. putrefaciens. However, XRD indicated that vivianite abundance was higher in experiments containing G. sulfurreducens, where it dominated. This study, therefore, shows that vivianite formation can be controlled to optimize yield during microbial processing of phosphate-loaded Fe(III) materials generated from water treatment processes.
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Affiliation(s)
- Lordina E Eshun
- University of Manchester, Department of Earth and Environmental Sciences, Geomicrobiology Group, Williamson Building, M13 9QQ, Oxford Road, Manchester, UK.
| | - Victoria S Coker
- University of Manchester, Department of Earth and Environmental Sciences, Geomicrobiology Group, Williamson Building, M13 9QQ, Oxford Road, Manchester, UK.
| | - Samuel Shaw
- University of Manchester, Department of Earth and Environmental Sciences, Geomicrobiology Group, Williamson Building, M13 9QQ, Oxford Road, Manchester, UK.
| | - Jonathan R Lloyd
- University of Manchester, Department of Earth and Environmental Sciences, Geomicrobiology Group, Williamson Building, M13 9QQ, Oxford Road, Manchester, UK.
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7
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Pang A, Zhang S, Zhang X, Liu H. Mechanism of Cr(VI) bioreduction by Clostridium sp. LQ25 under Fe(III) reducing conditions. CHEMOSPHERE 2024; 350:141099. [PMID: 38171403 DOI: 10.1016/j.chemosphere.2023.141099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 10/24/2023] [Accepted: 12/30/2023] [Indexed: 01/05/2024]
Abstract
The Cr(VI) bioreduction has attracted widespread attention in the field of Cr(VI) pollution remediation due to its environmental friendliness. Further in-depth research on the reduction mechanisms is necessary to enhance the efficiency of Cr(VI) bioreduction. However, the limited research on Cr(VI) bioreduction mechanisms remains a bottleneck for the practical application of Cr(VI) reduction. In this study, The Cr(VI) reduction of strain LQ25 was significantly improved when Fe(III) was used as an electron acceptor, which increased by 1.6-fold maximum within the set Cr(VI) concentration range. Based on this, the electron transfer process of Cr(VI) reduction was analyzed using strain LQ25. Based on genomic data, flavin proteins were found to interact closely with electron transfer-related proteins using protein-protein interaction (PPi) analysis. Transcriptome analysis revealed that flavin synthesis genes (ribE, ribBA, and ribH) and electron transfer flavoprotein genes (fixA, etfA, fixB, and etfB) were significantly upregulated when Fe(III) was used as the electron acceptor. These results indicate that the fermentative dissimilatory Fe(III)-reducing bacterial strain LQ25 mainly uses flavin as an electron shuttle for electron transfer, which differs from the common use of cytochrome c in respiratory bacteria. These findings on the mechanism of Cr(VI) bioreduction provide technical support for improving the efficiency of Cr(VI) reduction which promote the practical application of Cr(VI) bioreduction in the field of Cr(VI) pollution remediation.
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Affiliation(s)
- Anran Pang
- College of Marine and Environmental Sciences, Tianjin University of Science & Technology, China
| | - Shan Zhang
- College of Marine and Environmental Sciences, Tianjin University of Science & Technology, China
| | - Xiaodan Zhang
- College of Marine and Environmental Sciences, Tianjin University of Science & Technology, China
| | - Hongyan Liu
- College of Marine and Environmental Sciences, Tianjin University of Science & Technology, China.
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8
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Gao Y, Ren N, Wang S, Wu Y, Wang X, Li N. Low intensity magnetic separation of vivianite induced by iron reduction on the surface layer of Fe(III)[Fe(0)] iron scrap. ENVIRONMENTAL RESEARCH 2024; 240:117472. [PMID: 37871790 DOI: 10.1016/j.envres.2023.117472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 10/13/2023] [Accepted: 10/20/2023] [Indexed: 10/25/2023]
Abstract
Phosphorus (P) recovery through vivianite, which can be found in activated sludge, surplus sludge and digested sludge in the wastewater treatment plants (WWTPs), is a cutting-edge and efficient technology in recent years. However, how to generate and separate vivianite in an effective and economical way with natural iron oxide mineral was still the bottleneck to limit its application. Therefore, in this study, the P recovery efficiency (EP) and vivianite recovery efficiency (EV) of three kinds of iron oxides were investigated. We found that the EP of Akaganeite was 1.83 times and 4.88 times higher than that of Geothite and Hematite. Simultaneously, EV of Akaganeite was 1.64 times and 2.88 times higher than that of Geothite and Hematite. As Akaganeite is main component of rust on the surface of iron scrap, we used Fe(III)[Fe(0)] iron scrap with Fe(0) inside and Akaganeite outside as iron source and electron acceptor for vivianite production and magnetic separation. At the terminal stage (60 day), the P recovery efficiency with 20 g/L Fe(III)[Fe(0)] iron scrap was 36%. Applying a magnetical separator with magnetic field intensity of 0.3 T, vivianite was separated from the solution efficiently and immediately. Low intensity magnetic separation with iron scrap would recover P resources economically with the total cost to be $2.23/kg P, which was much lower than recovery via iron salts. Besides, it provided a significant insights into the P recovery and vivianite separation by reusing Fe waste during wastewater treatment.
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Affiliation(s)
- Yan Gao
- School of Environmental Science and Engineering, Tianjin University, No.92 Weijin Road, Nankai District, Tianjin, 300072, China.
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Shu Wang
- School of Environmental Science and Engineering, Tianjin University, No.92 Weijin Road, Nankai District, Tianjin, 300072, China
| | - Yu Wu
- School of Environmental Science and Engineering, Tianjin University, No.92 Weijin Road, Nankai District, Tianjin, 300072, China
| | - Xin Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin, 300350, China
| | - Nan Li
- School of Environmental Science and Engineering, Tianjin University, No.92 Weijin Road, Nankai District, Tianjin, 300072, China.
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9
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Ouyang B, Wei D, Wu B, Yan L, Gang H, Cao Y, Chen P, Zhang T, Wang H. In the View of Electrons Transfer and Energy Conversion: The Antimicrobial Activity and Cytotoxicity of Metal-Based Nanomaterials and Their Applications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2303153. [PMID: 37721195 DOI: 10.1002/smll.202303153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 08/28/2023] [Indexed: 09/19/2023]
Abstract
The global pandemic and excessive use of antibiotics have raised concerns about environmental health, and efforts are being made to develop alternative bactericidal agents for disinfection. Metal-based nanomaterials and their derivatives have emerged as promising candidates for antibacterial agents due to their broad-spectrum antibacterial activity, environmental friendliness, and excellent biocompatibility. However, the reported antibacterial mechanisms of these materials are complex and lack a comprehensive understanding from a coherent perspective. To address this issue, a new perspective is proposed in this review to demonstrate the toxic mechanisms and antibacterial activities of metal-based nanomaterials in terms of energy conversion and electron transfer. First, the antimicrobial mechanisms of different metal-based nanomaterials are discussed, and advanced research progresses are summarized. Then, the biological intelligence applications of these materials, such as biomedical implants, stimuli-responsive electronic devices, and biological monitoring, are concluded based on trappable electrical signals from electron transfer. Finally, current improvement strategies, future challenges, and possible resolutions are outlined to provide new insights into understanding the antimicrobial behaviors of metal-based materials and offer valuable inspiration and instructional suggestions for building future intelligent environmental health.
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Affiliation(s)
- Baixue Ouyang
- School of Metallurgy and Environment, Central South University, Changsha, 410083, P. R. China
| | - Dun Wei
- School of Metallurgy and Environment, Central South University, Changsha, 410083, P. R. China
| | - Bichao Wu
- School of Metallurgy and Environment, Central South University, Changsha, 410083, P. R. China
| | - Lvji Yan
- School of Metallurgy and Environment, Central South University, Changsha, 410083, P. R. China
| | - Haiying Gang
- School of Metallurgy and Environment, Central South University, Changsha, 410083, P. R. China
| | - Yiyun Cao
- School of Metallurgy and Environment, Central South University, Changsha, 410083, P. R. China
| | - Peng Chen
- School of Metallurgy and Environment, Central South University, Changsha, 410083, P. R. China
| | - Tingzheng Zhang
- School of Metallurgy and Environment, Central South University, Changsha, 410083, P. R. China
| | - Haiying Wang
- School of Metallurgy and Environment, Central South University, Changsha, 410083, P. R. China
- School of Metallurgy and Environment and Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Central South, University, Changsha, 410083, China
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10
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Zhang Y, O'Loughlin EJ, Park SY, Kwon MJ. Effects of Fe(III) (hydr)oxide mineralogy on the development of microbial communities originating from soil, surface water, groundwater, and aerosols. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:166993. [PMID: 37717756 DOI: 10.1016/j.scitotenv.2023.166993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/09/2023] [Accepted: 09/09/2023] [Indexed: 09/19/2023]
Abstract
Microbial Fe(III) reduction is a key component of the iron cycle in natural environments. However, the susceptibility of Fe(III) (hydr)oxides to microbial reduction varies depending on the mineral's crystallinity, and the type of Fe(III) (hydr)oxide in turn will affect the composition of the microbial community. We created microcosm reactors with microbial communities from four different sources (soil, surface water, groundwater, and aerosols), three Fe(III) (hydr)oxides (lepidocrocite, goethite, and hematite) as electron acceptors, and acetate as an electron donor to investigate the shaping effect of Fe(III) mineral type on the development of microbial communities. During a 10-month incubation, changes in microbial community composition, Fe(III) reduction, and acetate utilization were monitored. Overall, there was greater reduction of lepidocrocite than of goethite and hematite, and the development of microbial communities originating from the same source diverged when supplied with different Fe(III) (hydr)oxides. Furthermore, each Fe(III) mineral was associated with unique taxa that emerged from different sources. This study illustrates the taxonomic diversity of Fe(III)-reducing microbes from a broad range of natural environments.
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Affiliation(s)
- Yidan Zhang
- Department of Earth and Environmental Sciences, Korea University, Seoul 02841, South Korea
| | - Edward J O'Loughlin
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States
| | - Su-Young Park
- Department of Earth and Environmental Sciences, Korea University, Seoul 02841, South Korea
| | - Man Jae Kwon
- Department of Earth and Environmental Sciences, Korea University, Seoul 02841, South Korea.
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11
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Cheng M, Zhang H, Li Y, Chen W. Riboflavin secreted by Shewanella sp. FDL-2 facilitates its reduction of Se(iv) and Te(iv) by promoting electron transfer. RSC Adv 2023; 13:34445-34454. [PMID: 38024980 PMCID: PMC10667860 DOI: 10.1039/d3ra07093j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 11/18/2023] [Indexed: 12/01/2023] Open
Abstract
The biological reduction of selenite (Se(iv)) or tellurite (Te(iv)) to Se0 or Te0 has received increasing attention, as related studies have favored the development of Se/Te pollution control methods. In the presence of the electron donor, the microbes acquired energy and transferred electrons to Se(iv) or Te(iv) to achieve their detoxication. However, the microbial electron transfer pathways involved in this process are still not fully understood. In this study, we reported that marine Shewanella sp. FDL-2 (FDL-2) was capable of reducing Se(iv) and Te(iv) through a novel riboflavin-involved pathway. The results showed that FDL-2 can effectively reduce 10 mM Se(iv) and 5 mM Te(iv) to Se0 and Te0, which was further confirmed by XPS and XRD analyses. RT-qPCR results indicate the upregulation of genes coding flavin-related proteins, and the production of flavin-related substances by strain FDL-2 during Se(iv)/Te(iv) bioreduction was proven by fluorescence chromatography analysis. In addition, the presence of riboflavin enhanced the electron transfer efficiency, indicating its promoting effect on the bioreduction of Se(iv)/Te(iv). Overall, our results highlight a riboflavin-involved electron transfer pathway during Se(iv)/Te(iv) bioreduction and thus deepen our understanding of the corresponding mechanism.
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Affiliation(s)
- Manman Cheng
- Solid-State Fermentation Resource Utilization Key Laboratory of Sichuan Province, Yibin University Yibin City Sichuan Province 644000 China
- College of Life Sciences, Yantai University Yantai 264000 China
| | - Haikun Zhang
- Yantai Institute of Costal Zone Research, Chinese Academy of Sciences Yantai 264000 China
| | - Yan Li
- College of Life Sciences, Yantai University Yantai 264000 China
| | - Wenhao Chen
- Solid-State Fermentation Resource Utilization Key Laboratory of Sichuan Province, Yibin University Yibin City Sichuan Province 644000 China
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12
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Fang L, Chi J, Shi Q, Wu Y, Li F. Facet-dependent electron transfer induces distinct arsenic reallocations on hematite. WATER RESEARCH 2023; 242:120180. [PMID: 37320876 DOI: 10.1016/j.watres.2023.120180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/31/2023] [Accepted: 06/06/2023] [Indexed: 06/17/2023]
Abstract
The interfacial electron transfer (ET) between electron shuttling compounds and iron (Fe) oxyhydroxides plays a crucial role in the reductive dissolution of Fe minerals and the fate of surface-bound arsenic (As). However, the impact of exposed facets of highly crystalline hematite on reductive dissolution and As immobilization is poorly understood. In this study, we systematically investigated the interfacial processes of the electron shuttling compound cysteine (Cys) on various facets of hematite and the reallocations of surface-bound As(III) or As(V) on the respective surfaces. Our results demonstrate that the ET process between Cys and hematite generates Fe(II) and leads to reductive dissolution, with more Fe(II) generated on {001} facets of exposed hematite nanoplates (HNPs). Reductive dissolution of hematite leads to significantly enhanced As(V) reallocations on hematite. Nevertheless, upon the addition of Cys, a raipd release of As(III) can be halted by its prompt re-adsorption, leaving the extent of As(III) immobilization on hematite unchanged throughout the course of reductive dissolution. This is due to that Fe(II) can form new precipitates with As(V), a process that is facet-dependent and influenced by water chemistry. Electrochemical analysis reveals that HNPs exhibit higher conductivity and ET ability, which is beneficial for reductive dissolution and As reallocations on hematite. These findings highlight the facet-dependent reallocations of As(III) and As(V) facilitated by electron shuttling compounds and have implications for the biogeochemical processes of As in soil and subsurface environments.
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Affiliation(s)
- Liping Fang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Jialin Chi
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Qiantao Shi
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, United States
| | - Yundang Wu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Fangbai Li
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China.
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13
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Xu R, Wang YN, Sun Y, Wang H, Gao Y, Li S, Guo L, Gao L. External sodium acetate improved Cr(VI) stabilization in a Cr-spiked soil during chemical-microbial reduction processes: Insights into Cr(VI) reduction performance, microbial community and metabolic functions. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 251:114566. [PMID: 36680991 DOI: 10.1016/j.ecoenv.2023.114566] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/11/2023] [Accepted: 01/18/2023] [Indexed: 06/17/2023]
Abstract
Interest combined chemical and microbial reduction for Cr(VI) remediation in contaminated sites has greatly increased. However, the effect of external carbon sources on Cr(VI) reduction during chemical-microbial reduction processes has not been studied. Therefore, in this study, the role of external sodium acetate (SA) in improving Cr(VI) reduction and stabilization in a representative Cr(VI)-spiked soils was systemically investigated. The results of batch experiments suggested that the soil Cr(VI) content declined from 1000 mg/kg to 2.6-5.1 mg/kg at 1-5 g C/kg SA supplemented within 15 days of reaction. The external addition of SA resulted in a significant increase in the relative abundances of Cr(VI)-reducing microorganisms, such as Tissierella, Proteiniclasticum and Proteiniclasticum. The relative abundance of Tissierella increased from 9.1% to 29.8% with the SA treatment at 5 g C/kg soil, which was the main contributors to microbial Cr(VI) reduction. Redundancy analysis indicated that pH and SA were the predominant factors affecting the microbial community in the SA treatments at 2 g C/kg soil and 5 g C/kg soil. Functional prediction suggested that the addition of SA had a positive effect on the metabolism of key substances involved in Cr(VI) microbial reduction. This work provides new insightful guidance on Cr(VI) remediation in contaminated soils.
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Affiliation(s)
- Rong Xu
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, China
| | - Ya-Nan Wang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, China
| | - Yingjie Sun
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, China
| | - Huawei Wang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, China.
| | - Ying Gao
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, China
| | - Shupeng Li
- Beijing Construction Engineering Environmental Remediation Co., Ltd., National Engineering Laboratory for Safety Remediation of Contaminated Sites, Beijing 100015, China
| | - Lili Guo
- Beijing Construction Engineering Environmental Remediation Co., Ltd., National Engineering Laboratory for Safety Remediation of Contaminated Sites, Beijing 100015, China
| | - Lei Gao
- School of Marine Sciences and Engineering, Nanjing Normal University, Nanjing, China.
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14
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The Differing Roles of Flavins and Quinones in Extracellular Electron Transfer in Lactiplantibacillus plantarum. Appl Environ Microbiol 2023; 89:e0131322. [PMID: 36533923 PMCID: PMC9888254 DOI: 10.1128/aem.01313-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Lactiplantibacillus plantarum is a lactic acid bacterium that is commonly found in the human gut and fermented food products. Despite its overwhelmingly fermentative metabolism, this microbe can perform extracellular electron transfer (EET) when provided with an exogenous quinone, 1,4-dihydroxy-2-naphthoic acid (DHNA), and riboflavin. However, the separate roles of DHNA and riboflavin in EET in L. plantarum have remained unclear. Here, we seek to understand the role of quinones and flavins in EET by monitoring iron and anode reduction in the presence and absence of these small molecules. We found that addition of either DHNA or riboflavin can support robust iron reduction, indicating electron transfer to extracellular iron occurs through both flavin-dependent and DHNA-dependent routes. Using genetic mutants of L. plantarum, we found that flavin-dependent iron reduction requires Ndh2 and EetA, while DHNA-dependent iron reduction largely relies on Ndh2 and PplA. In contrast to iron reduction, DHNA-containing medium supported more robust anode reduction than riboflavin-containing medium, suggesting electron transfer to an anode proceeds most efficiently through the DHNA-dependent pathway. Furthermore, we found that flavin-dependent anode reduction requires EetA, Ndh2, and PplA, while DHNA-dependent anode reduction requires Ndh2 and PplA. Taken together, we identify multiple EET routes utilized by L. plantarum and show that the EET route depends on access to environmental biomolecules and on the electron acceptor. This work expands our molecular-level understanding of EET in Gram-positive microbes and provides additional opportunities to manipulate EET for biotechnology. IMPORTANCE Lactic acid bacteria are named because of their nearly exclusive fermentative metabolism. Thus, the recent observation of EET activity-typically associated with anaerobic respiration-in this class of organisms has forced researchers to rethink the rules governing microbial metabolic strategies. Our identification of multiple routes for EET in L. plantarum that depend on two different redox active small molecules expands our understanding of how microbes metabolically adapt to different environments to gain an energetic edge and how these processes can be manipulated for biotechnological uses. Understanding the role of EET in lactic acid bacteria is of great importance due to the significance of lactic acid bacteria in agriculture, bioremediation, food production, and gut health. Furthermore, the maintenance of multiple EET routes speaks to the importance of this process to function under a variety of environmental conditions.
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15
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Lv L, Sun L, Yuan C, Han Y, Huang Z. The combined enhancement of RL, nZVI and AQDS on the microbial anaerobic-aerobic degradation of PAHs in soil. CHEMOSPHERE 2022; 307:135609. [PMID: 35809750 DOI: 10.1016/j.chemosphere.2022.135609] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 06/11/2022] [Accepted: 07/03/2022] [Indexed: 06/15/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous persistent organic pollutants in soil, which have carcinogenic, teratogenic and mutagenic hazards. The effects of rhamnolipid (RL), nano zero-valent iron (nZVI), and anthraquinone-2,6-disulfonic acid (AQDS) on the degradation of PAHs in soil were studied. It was found that the treatment of 5 mg·kg-1RL + 1% nZVI +0.2 mmol·kg-1AQDS had the highest degradation rate. The degradation rate of total PAHs and HMW-PAHs was 72.81% and 79.47% respectively after 90 days. High-throughput sequencing showed that in RL + nZVI + AQDS enhanced soil, Clostridium, Geobacter, Anaeromyxobacter and Sphingomonas were the dominant species for anaerobic degradation of PAHs. Rhodococcus, Nocardioides, and Microvirga are the dominant species for aerobic degradation of PAHs. The activities of methyltransferase, dehydrogenase and catechol 1,2-dioxygenase in the anaerobic-aerobic degradation process of PAHs were consistent with the degradation process of PAHs, indicating the role of these enzymes in the degradation of PAHs. RL, nZVI, and AQDS combined enhanced microbial anaerobic-aerobic degradation has great application potential in remediation of PAHs-contaminated soil.
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Affiliation(s)
- Lianghe Lv
- Key Laboratory of Ecological Restoration of Regional Pollution Environment, Ministry of Education, Shenyang University, Shenyang, 110004, China
| | - Lina Sun
- Key Laboratory of Ecological Restoration of Regional Pollution Environment, Ministry of Education, Shenyang University, Shenyang, 110004, China.
| | - Chunli Yuan
- Key Laboratory of Ecological Restoration of Regional Pollution Environment, Ministry of Education, Shenyang University, Shenyang, 110004, China.
| | - Yue Han
- Key Laboratory of Ecological Restoration of Regional Pollution Environment, Ministry of Education, Shenyang University, Shenyang, 110004, China
| | - Zhaohui Huang
- Key Laboratory of Ecological Restoration of Regional Pollution Environment, Ministry of Education, Shenyang University, Shenyang, 110004, China
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16
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Yu L, Cheng WX, Wang Q. The enhancement on biohydrogen production by the driving forces from extracellular iron oxide respiration. BIORESOURCE TECHNOLOGY 2022; 361:127679. [PMID: 35878766 DOI: 10.1016/j.biortech.2022.127679] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
Biohydrogen productions from xylose and glucose under dark condition were enhanced by the presence of natural Fe3O4. The electron equivalent of H2 fractions accounted for 4.55 % and 5.69 % of the total given xylose and glucose in the experiments without Fe3O4, and that were correspondingly increased to 5.14 % and 6.50 % in the experiments with 100 mg/L of Fe3O4, respectively. Moreover, Fe3O4 increased the total intracellular NAD(H) concentrations by 8.84 % and 8.37 %, and boosted the ratios of NADH/NAD+ by 8.33 % and 17.72 % in xylose and glucose fermentation, respectively, comparing to the corresponding control experiments. The formation of electron couples of Fe(III)/Fe(II) during the iron oxide respiration and more generation of active extracellular polymeric substances components were determined as the important reasons for the improved biohydrogen production performance. Thus, a promotion mechanism of the internal "driving forces" from extracellular iron oxide respiration on the biohydrogen production was proposed.
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Affiliation(s)
- Lei Yu
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China; College of Biology and the Environment, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China
| | - Wei-Xin Cheng
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Quan Wang
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China; College of Biology and the Environment, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China.
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17
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Li R, Xian Y, Gao Y, Sun Y, Zhang D, Zhao J. New insight into the mechanism of remediation of chromium containing soil by synergetic disposal of ferrous sulfate and digestate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 837:155539. [PMID: 35489493 DOI: 10.1016/j.scitotenv.2022.155539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 06/14/2023]
Abstract
In this work, an innovative technology by using ferrous sulfate combined with digestate, was applied to the Cr (VI) reduction. In the combined process, 3% ferrous sulfate, 5% digestate, 2% glucose, 30 °C and 50% moisture content were proved to be the optimal operating conditions. The combined process achieved 100% reduction of 3000 mg/Kg Cr (VI) within 10 days. Ferrous sulfate and digestate had a synergistic effect on Cr (VI) reduction. XPS analysis showed that Cr (VI) was reduced to Cr (III) in the combined treatment group. Functional microorganisms in digestate played an important role in the reduction of Cr (VI). Sulfate and Fe(III) could be reduced by microorganisms in digestate, and the reduction products accelerated the reduction of Cr (VI). The combined treatment improved the relative abundance of Clostridium, Acinetobacter, and Tissierella, which were of great significance for the reduction of Cr (VI).
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Affiliation(s)
- Rongqiang Li
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, China
| | - Yingzhuo Xian
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, China
| | - Ying Gao
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, China
| | - Yingjie Sun
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, China
| | - Dalei Zhang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, China; Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China.
| | - Jianwei Zhao
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, China.
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18
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Srivastava P, Al-Obaidi SA, Webster G, Weightman AJ, Sapsford DJ. Towards passive bioremediation of dye-bearing effluents using hydrous ferric oxide wastes: Mechanisms, products and microbiology. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 317:115332. [PMID: 35617861 DOI: 10.1016/j.jenvman.2022.115332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 04/14/2022] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
A novel, circular economy-inspired approach for the "passive" (non-powered and reagent-free) treatment of dye-bearing effluent is presented. The treatment utilises the biogeochemical interaction of dye-bearing wastewater with hydrous ferric oxide (HFO) bearing sludges. The work presented demonstrates for the first time the reuse of HFO-rich waste sludges from potable water and mine water treatment. The waste was used directly without modification or reagent addition, as media/substrate in simple flow-through reactors for the decolourisation and biodegradation of methyl orange (MO) and mixed dyes textile effluent. Three phases of exploratory proof of concept work were undertaken. Columns containing HFO sludges were challenged with solution of MO, and MO amended with glycerol (Phase I), MO in a synthetic textile effluent recipe (Phase II), and real mixed textile effluent containing a mixture of dyes (Phase III). After an initial lag period extensive decolourisation of dye was observed in all cases at rates comparable with pure strains and engineered bioreactor processes, with evidence of biodegradation beyond simple cleavage of the mono azo chromophore and mineralisation. The microbiology of the initial sludge samples in both cases exhibited a diverse range of iron oxidising and reducing bacteria. However, post experiment the microbiology of sludge evolved from being dominated by Proteobacteria to being dominated by Firmicutes. Distinct changes in the microbial community structure were observed in post-treatment MWTS and WTWS where genera capable of iron and sulphate reduction and/or aromatic amine degradation were identified. Average nitrogen removal rates for the columns ranged from 27.8 to 194 g/m3/day which is higher than engineered sequential anaerobic-aerobic bioreactor. Postulated mechanisms for the fast anaerobic decolourisation, biodegradation, and mineralisation of the dyes (as well nitrogen transformations) include various direct and indirect enzymatic and metabolic reactions, as well as reductive attack by continuously regenerated reductants such as Fe(II), HFO bound Fe(II), FeS, and HS-. The ability of iron reducers to degrade aromatic rings is also considered important in the further biodegradation and complete mineralisation of organic carbon. The study reveals that abundant and ubiquitous HFO-rich waste sludges, can be used without amendment, as a substrate in simple flow-through bioremediation system for the decolourisation and partial biodegradation of dyes in textile effluent.
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Affiliation(s)
- Pallavee Srivastava
- School of Engineering, Cardiff University, Queen's Building, The Parade, Cardiff, CF24 3AA, United Kingdom.
| | - Safaa A Al-Obaidi
- School of Engineering, Cardiff University, Queen's Building, The Parade, Cardiff, CF24 3AA, United Kingdom
| | - Gordon Webster
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, United Kingdom
| | - Andrew J Weightman
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, United Kingdom
| | - Devin J Sapsford
- School of Engineering, Cardiff University, Queen's Building, The Parade, Cardiff, CF24 3AA, United Kingdom
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19
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Biofilm Development on Carbon Steel by Iron Reducing Bacterium Shewanella putrefaciens and Their Role in Corrosion. METALS 2022. [DOI: 10.3390/met12061005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Microscopic, electrochemical and surface characterization techniques were used to investigate the effects of iron reducing bacteria (IRB) biofilm on carbon steel corrosion for 72 and 168 h under batch conditions. The organic nutrient availability for the bacteria was varied to evaluate biofilms formed under nutritionally rich, as compared to nutritionally deficient, conditions. Focused ion beam-scanning electron microscopy (FIB-SEM) was used to investigate the effect of subsurface biofilm structures on the corrosion characteristics of carbon steel. Hydrated biofilms produced by IRB were observed under environmental scanning electron microscope (ESEM) with minimal surface preparation, and the elemental composition of the biofilms was investigated using energy dispersive spectroscopy (EDX). Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) was used to provide information on the organic and inorganic chemical makeup of the biofilms. Electrochemical techniques employed for assessing corrosion, by open circuit potential, linear polarization and potentiodynamic polarization tests indicated no significant difference in the corrosion resistance for carbon steel in IRB-inoculated, compared to the abiotic solutions of common Postgate C after 72 and 168 h. However, the steel was found to be more susceptible to corrosion when the yeast extract was removed from the biotic environment for the 168 h test. In the absence of yeast nutrient, it is postulated that IRB received energy by transforming the protective film of Fe3+ into more soluble Fe2+ products.
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20
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Electron transfer in Gram-positive bacteria: enhancement strategies for bioelectrochemical applications. World J Microbiol Biotechnol 2022; 38:83. [DOI: 10.1007/s11274-022-03255-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/21/2022] [Indexed: 12/30/2022]
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21
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Liu K, Li F, Pang Y, Fang L, Hocking R. Electron shuttle-induced oxidative transformation of arsenite on the surface of goethite and underlying mechanisms. JOURNAL OF HAZARDOUS MATERIALS 2022; 425:127780. [PMID: 34801297 DOI: 10.1016/j.jhazmat.2021.127780] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/25/2021] [Accepted: 11/10/2021] [Indexed: 06/13/2023]
Abstract
The redox process of electron shuttles like cysteine on iron minerals under aerobic conditions may largely determine the fate of arsenic (As) in soils, while the interfacial processes and underlying mechanisms are barely explored. This work systematically investigates the interfacial oxidation processes of As(III) on goethite induced by cysteine. Results show that the addition of cysteine significantly enhances the oxidation efficiency (~ 40%) of As(III) (C0: 10 mg/L) by goethite at pH 7 under aerobic conditions, which is 19.5 times of that without cysteine. cysteine induces Fe(III) reduction on the surface of goethite, and the generation absorbed Fe(II) species play an important role in As(III) oxidation. In particular, the further complexation of Fe(II) with cysteine is thermodynamically favorable for electron transfer, leading to an enhanced As(III) oxidation efficiency. The oxidation efficiency of As(III) in the goethite/cysteine system increases by increasing cysteine concentration and decreases by elevating pH conditions. In addition, evidence indicates that •O2- radicals account for approximately 80% of total oxidized As(III). Meanwhile, only 16% of As(III) oxidation can be attributed to the formed •OH radicals. This work provides new insight into the role of organic electron shuttling compounds in determining As cycling in soils.
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Affiliation(s)
- Kai Liu
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangzhou 510650, China
| | - Fangbai Li
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangzhou 510650, China
| | - Yan Pang
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangzhou 510650, China
| | - Liping Fang
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangzhou 510650, China.
| | - Rosalie Hocking
- Department of Chemistry and Biotechnology and Centre for Translational Atomaterials, Swinburne University of Technology, Hawthorn, Melbourne, VIC 3122, Australia
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22
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Lu Y, Hu Y, Tang L, Xie Q, Liu Q, Zhong L, Fu L, Fan C. Effects and mechanisms of modified biochars on microbial iron reduction of Geobacter sulfurreducens. CHEMOSPHERE 2021; 283:130983. [PMID: 34153910 DOI: 10.1016/j.chemosphere.2021.130983] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 04/30/2021] [Accepted: 05/22/2021] [Indexed: 06/13/2023]
Abstract
Biochar was proved as an electron shuttle to facilitate extracellular electron transfer (EET) of electrochemically active bacteria (EAB); however, its underlying mechanism was not fully understood. In this study, we aimed to further explore how the regulation of surface functional groups of biochar would affect the microbial iron reduction process of Geobacter sulfurreducens as a typical EAB. Two modified biochars were achieved after HNO3 (NBC) and NaBH4 (RBC) pretreatments, and a control biochar was produced after deionized water (WBC) washing. Results showed that WBC and RBC significantly accelerated microbial iron reduction of G. sulfurreducens PCA, while had no effect in the final Fe (II) minerals (e.g., vivianite and green rust (CO32-)). Besides, Brunauer-Emmett-Teller (BET) surface area, electron spin resonance (ESR) and electrochemical measurements showed that larger surface area, lower redox potential, and more redox-active groups (e.g., aromatic structures and quinone/hydroquinone moieties) in RBC explained its better electron transfer performance comparing to WBC. Interestingly, NBC completely suppressed the Fe (III) reduction process, mainly due to the production of reactive oxygen species which inhibited the growth of G. sulfurreducens PCA. Overall, this work paves a feasible way to regulate the surface functional groups for biochar, and comprehensively revealed its effect on EET process of microorganisms.
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Affiliation(s)
- Yue Lu
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, Hunan, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, Hunan, China.
| | - Yingju Hu
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, Hunan, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, Hunan, China
| | - Lin Tang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, Hunan, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, Hunan, China.
| | - Qingqing Xie
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, Hunan, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, Hunan, China
| | - Qian Liu
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, Hunan, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, Hunan, China
| | - Linrui Zhong
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, Hunan, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, Hunan, China
| | - Leiling Fu
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, Hunan, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, Hunan, China
| | - Changzheng Fan
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, Hunan, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, Hunan, China
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23
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Wu Y, Wang Z, Xu L, Feng W, Fan H. Temporal responses of hydrochemical variables and dissolved Fe(II) to flooding at a lake riparian wetland under different vegetation revealing by high resolution DGT. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 294:112930. [PMID: 34118515 DOI: 10.1016/j.jenvman.2021.112930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 04/14/2021] [Accepted: 05/09/2021] [Indexed: 06/12/2023]
Abstract
The interplay between hydrological and biogeochemical processes in riparian wetland was recognized to lead directly to the temporal variations of surface water quality. However, the effects of flooding and vegetation on the release and entrapment of heavy metals and nutrients in riparian wetland remain poorly understood. The study aimed at investigating the influences of flooding and vegetation on the hydrochemical and Fe-redox change in the soil porewater and shallow groundwater, in Poyang lake riparian wetland through hydrochemical monitoring and diffusive gradient technology (DGT). The hydrochemical profiles and results of PCA analysis on the temporal datasets both demonstrated that vegetation had significant influences on the hydrochemistry of rhizosphere depth zone (RDZ) and shallow groundwater depth zone (SGZ). The Ca, K, Na, Mg, Mn and DOC at RDZ of both plants showed significant increasing trends from pre-to post-flooding while were observed minor change at the SGZ. The extracted PC1-PC3 from PCA analysis suggested that mineral dissolution and fermentation were dominating processes that explained 64.1% of the hydrochemical variability under the wetting-drying cycle. The synchronous changes of Fe(II), SO42-, DOC and ORP were found to occur at the SGZ of Carex, implying the likely occurrence of Fe- and S- redox reactions. The Fe(II) DGT profiles evidenced the temporal iron reduction and oxidation occurring at the rhizosphere following the wetting-drying cycle, as also reflected by the high opposite Fe2+ and DO association through PCA analysis. The high resolution temporal-spatial Fe(II) distribution suggested also the interface between lake water and groundwater was relatively stable under flooding. These results highlight that the release of dissolved Fe(II) from the wetland rhizosphere driven by flood may result in the release of Fe-associated heavy metals from riparian wetland to surface water, and hence pose potential threats to the surface water quality. Thereby, the flow and flood should be properly controlled and vegetation effects need to be carefully considered in the water resources management of lake-floodplain system.
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Affiliation(s)
- Yuexia Wu
- Nanjing University of Finance & Economics, Institute of Innovation & Entrepreneurship, Nanjing, 210023, PR China; Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography & Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China.
| | - Zhenglu Wang
- College of Oceanography, Hohai University, Nanjing, Jiangsu, 210098, PR China
| | - Ligang Xu
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography & Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China
| | - Wenjuan Feng
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography & Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, PR China
| | - Hongxiang Fan
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography & Limnology, Chinese Academy of Sciences, Nanjing, 210008, PR China
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Gurumurthy DM, Bilal M, Nadda AK, Reddy VD, Saratale GD, Guzik U, Ferreira LFR, Gupta SK, Savanur MA, Mulla SI. Evaluation of cell wall-associated direct extracellular electron transfer in thermophilic Geobacillus sp. 3 Biotech 2021; 11:383. [PMID: 34350088 DOI: 10.1007/s13205-021-02917-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 07/05/2021] [Indexed: 11/25/2022] Open
Abstract
In this study, a cell wall-associated extracellular electron transfer (EET) was determined in the thermophilic Geobacillus sp. to utilize iron as a terminal electron acceptor. The direct extracellular transfer of its electrons was primarily linked to the cell wall cytochrome-c and diffusible redox mediators like flavins during the anoxic condition. Based on the azo dye decolouration and protein film voltammetry, it was revealed that, in the absence of surface polysaccharide and diffusible mediators, the cell wall-associated EET pathway was likely to be a favorable mechanism in Geobacillus sp. Since the permeability of such redox molecule is primarily limited to the cell wall, the electron transfer occurs by direct contact with cell wall-associated cytochrome and final electron acceptor. Furthermore, transfer of electrons with the help of redox shuttling molecules like riboflavin from cytochrome to cells, vice versa indicates that Geoabcillus sp. has adopted this unique pathway during an anoxic environment for its respiration. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s13205-021-02917-2.
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Affiliation(s)
| | - Muhammad Bilal
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, China
| | - Ashok Kumar Nadda
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, 173234 Himachal Pradesh India
| | - Vaddi Damodara Reddy
- Department of Biochemistry, School of Applied Sciences, REVA University, Bangalore, 560 064 India
| | - Ganesh Dattatraya Saratale
- Department of Food Science and Biotechnology, Dongguk University-Seoul, Ilsandong-gu, Goyang, Gyeonggi 10326 Republic of Korea
| | - Urszula Guzik
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Science , University of Silesia in Katowice, Jagiellonska 28, 40-032 Katowice, Poland
| | - Luiz Fernando Romanholo Ferreira
- Graduate Program in Process Engineering , Tiradentes University, Av. Murilo Dantas, 300, Farolândia, Aracaju, Sergipe 49032-490 Brazil
| | - Sanjay Kumar Gupta
- Environmental Engineering, Department of Civil Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016 India
| | | | - Sikandar I Mulla
- Department of Biochemistry, School of Applied Sciences, REVA University, Bangalore, 560 064 India
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25
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Tu Z, Lopes HDFS, Narihiro T, Yumoto I. The Mechanism Underlying of Long-Term Stable Indigo Reduction State in Indigo Fermentation Using Sukumo (Composted Polygonum tinctorium Leaves). Front Microbiol 2021; 12:698674. [PMID: 34367099 PMCID: PMC8342947 DOI: 10.3389/fmicb.2021.698674] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/30/2021] [Indexed: 01/04/2023] Open
Abstract
Indigo fermentation fluid maintains its indigo-reducing state for more than 6 months under open-air. To elucidate the mechanism underlying the sustainability of this indigo reduction state, three indigo fermentation batches with different durations for the indigo reduction state were compared. The three examined batches exhibited different microbiota and consisted of two phases. In the initial phase, oxygen-metabolizing-bacteria derived from sukumo established an initial network. With decreasing redox potential (ORP), the initial bacterial community was replaced by obligate anaerobes (mainly Proteinivoraceae; phase 1). Approximately 1 month after the beginning of fermentation, the predominating obligate anaerobes were decreased, and Amphibacillus and Polygonibacillus, which can decompose macromolecules derived from wheat bran, were predominantly observed, and the transition of microbiota became slow (phase 2). Considering the substrate utilization ability of the dominated bacterial taxa, the transitional change from phase 1 to phase 2 suggests that this changed from the bacterial flora that utilizes substrates derived from sukumo, including intrinsic substrates in sukumo and weakened or dead bacterial cells derived from early events (heat and alkaline treatment and reduction of ORP) to that of wheat bran-utilizers. This succession was directly related to the change in the major substrate sustaining the corresponding community and the turning point was approximately 1 month after the start of fermentation. As a result, we understand that the role of sukumo includes changes in the microbial flora immediately after the start of fermentation, which has an important function in the start-up phase of fermentation, whereas the ecosystem comprised of the microbiota utilizing wheat bran underpins the subsequent long-term indigo reduction.
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Affiliation(s)
- Zhihao Tu
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan.,Laboratory of Environmental Microbiology, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Helena de Fátima Silva Lopes
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan.,Laboratory of Environmental Microbiology, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Takashi Narihiro
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan
| | - Isao Yumoto
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan.,Laboratory of Environmental Microbiology, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
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Bio-Electrochemical System Depollution Capabilities and Monitoring Applications: Models, Applicability, Advanced Bio-Based Concept for Predicting Pollutant Degradation and Microbial Growth Kinetics via Gene Regulation Modelling. Processes (Basel) 2021. [DOI: 10.3390/pr9061038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Microbial fuel cells (MFC) are an emerging technology for waste, wastewater and polluted soil treatment. In this manuscript, pollutants that can be treated using MFC systems producing energy are presented. Furthermore, the applicability of MFC in environmental monitoring is described. Common microbial species used, release of genome sequences, and gene regulation mechanisms, are discussed. However, although scaling-up is the key to improving MFC systems, it is still a difficult challenge. Mathematical models for MFCs are used for their design, control and optimization. Such models representing the system are presented here. In such comprehensive models, microbial growth kinetic approaches are essential to designing and predicting a biosystem. The empirical and unstructured Monod and Monod-type models, which are traditionally used, are also described here. Understanding and modelling of the gene regulatory network could be a solution for enhancing knowledge and designing more efficient MFC processes, useful for scaling it up. An advanced bio-based modelling concept connecting gene regulation modelling of specific metabolic pathways to microbial growth kinetic models is presented here; it enables a more accurate prediction and estimation of substrate biodegradation, microbial growth kinetics, and necessary gene and enzyme expression. The gene and enzyme expression prediction can also be used in synthetic and systems biology for process optimization. Moreover, various MFC applications as a bioreactor and bioremediator, and in soil pollutant removal and monitoring, are explored.
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Byrd N, Lloyd JR, Small JS, Taylor F, Bagshaw H, Boothman C, Morris K. Microbial Degradation of Citric Acid in Low Level Radioactive Waste Disposal: Impact on Biomineralization Reactions. Front Microbiol 2021; 12:565855. [PMID: 33995289 PMCID: PMC8114274 DOI: 10.3389/fmicb.2021.565855] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/10/2021] [Indexed: 11/18/2022] Open
Abstract
Organic complexants are present in some radioactive wastes and can challenge waste disposal as they may enhance subsurface mobility of radionuclides and contaminant species via chelation. The principal sources of organic complexing agents in low level radioactive wastes (LLW) originate from chemical decontamination activities. Polycarboxylic organic decontaminants such as citric and oxalic acid are of interest as currently there is a paucity of data on their biodegradation at high pH and under disposal conditions. This work explores the biogeochemical fate of citric acid, a model decontaminant, under high pH anaerobic conditions relevant to disposal of LLW in cementitious disposal environments. Anaerobic microcosm experiments were set up, using a high pH adapted microbial inoculum from a well characterized environmental site, to explore biodegradation of citrate under representative repository conditions. Experiments were initiated at three different pH values (10, 11, and 12) and citrate was supplied as the electron donor and carbon source, under fermentative, nitrate-, Fe(III)- and sulfate- reducing conditions. Results showed that citrate was oxidized using nitrate or Fe(III) as the electron acceptor at > pH 11. Citrate was fully degraded and removed from solution in the nitrate reducing system at pH 10 and pH 11. Here, the microcosm pH decreased as protons were generated during citrate oxidation. In the Fe(III)-reducing systems, the citrate removal rate was slower than in the nitrate reducing systems. This was presumably as Fe(III)-reduction consumes fewer moles of citrate than nitrate reduction for the same molar concentrations of electron acceptor. The pH did not change significantly in the Fe(III)-reducing systems. Sulfate reduction only occurred in a single microcosm at pH 10. Here, citrate was fully removed from solution, alongside ingrowth of acetate and formate, likely fermentation products. The acetate and lactate were subsequently used as electron donors during sulfate-reduction and there was an associated decrease in solution pH. Interestingly, in the Fe(III) reducing experiments, Fe(II) ingrowth was observed at pH values recorded up to 11.7. Here, TEM analysis of the resultant solid Fe-phase indicated that nanocrystalline magnetite formed as an end product of Fe(III)-reduction under these extreme conditions. PCR-based high-throughput 16S rRNA gene sequencing revealed that bacteria capable of nitrate Fe(III) and sulfate reduction became enriched in the relevant, biologically active systems. In addition, some fermentative organisms were identified in the Fe(III)- and sulfate-reducing systems. The microbial communities present were consistent with expectations based on the geochemical data. These results are important to improve long-term environmental safety case development for cementitious LLW waste disposal.
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Affiliation(s)
- Natalie Byrd
- Department of Earth and Environmental Sciences, Research Centre for Radwaste Disposal and Williamson Research Centre, The University of Manchester, Manchester, United Kingdom
| | - Jonathan R Lloyd
- Department of Earth and Environmental Sciences, Research Centre for Radwaste Disposal and Williamson Research Centre, The University of Manchester, Manchester, United Kingdom
| | - Joe S Small
- Department of Earth and Environmental Sciences, Research Centre for Radwaste Disposal and Williamson Research Centre, The University of Manchester, Manchester, United Kingdom.,National Nuclear Laboratory, Warrington, United Kingdom
| | - Frank Taylor
- Low Level Waste Repository Ltd., Seascale, United Kingdom
| | - Heath Bagshaw
- School of Engineering, The University of Liverpool, Liverpool, United Kingdom
| | - Christopher Boothman
- Department of Earth and Environmental Sciences, Research Centre for Radwaste Disposal and Williamson Research Centre, The University of Manchester, Manchester, United Kingdom
| | - Katherine Morris
- Department of Earth and Environmental Sciences, Research Centre for Radwaste Disposal and Williamson Research Centre, The University of Manchester, Manchester, United Kingdom
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Palacios PA, Francis WR, Rotaru AE. A Win-Loss Interaction on Fe 0 Between Methanogens and Acetogens From a Climate Lake. Front Microbiol 2021; 12:638282. [PMID: 34054747 PMCID: PMC8158942 DOI: 10.3389/fmicb.2021.638282] [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: 12/05/2020] [Accepted: 03/29/2021] [Indexed: 12/23/2022] Open
Abstract
Diverse physiological groups congregate into environmental corrosive biofilms, yet the interspecies interactions between these corrosive physiological groups are seldom examined. We, therefore, explored Fe0-dependent cross-group interactions between acetogens and methanogens from lake sediments. On Fe0, acetogens were more corrosive and metabolically active when decoupled from methanogens, whereas methanogens were more metabolically active when coupled with acetogens. This suggests an opportunistic (win-loss) interaction on Fe0 between acetogens (loss) and methanogens (win). Clostridia and Methanobacterium were the major candidates doing acetogenesis and methanogenesis after four transfers (metagenome sequencing) and the only groups detected after 11 transfers (amplicon sequencing) on Fe0. Since abiotic H2 failed to explain the high metabolic rates on Fe0, we examined whether cell exudates (spent media filtrate) promoted the H2-evolving reaction on Fe0 above abiotic controls. Undeniably, spent media filtrate generated three- to four-fold more H2 than abiotic controls, which could be partly explained by thermolabile enzymes and partly by non-thermolabile constituents released by cells. Next, we examined the metagenome for candidate enzymes/shuttles that could catalyze H2 evolution from Fe0 and found candidate H2-evolving hydrogenases and an almost complete pathway for flavin biosynthesis in Clostridium. Clostridial ferredoxin-dependent [FeFe]-hydrogenases may be catalyzing the H2-evolving reaction on Fe0, explaining the significant H2 evolved by spent media exposed to Fe0. It is typical of Clostridia to secrete enzymes and other small molecules for lytic purposes. Here, they may secrete such molecules to enhance their own electron uptake from extracellular electron donors but indirectly make their H2-consuming neighbors-Methanobacterium-fare five times better in their presence. The particular enzymes and constituents promoting H2 evolution from Fe0 remain to be determined. However, we postulate that in a static environment like corrosive crust biofilms in lake sediments, less corrosive methanogens like Methanobacterium could extend corrosion long after acetogenesis ceased, by exploiting the constituents secreted by acetogens.
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Affiliation(s)
| | | | - Amelia-Elena Rotaru
- Nordcee, Department of Biology, University of Southern Denmark, Odense, Denmark
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29
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Chen L, Wang M, Feng Y, Xu X, Luo X, Zhang Z. Production of bioelectricity may play an important role for the survival of Xanthomonas campestris pv. campestris (Xcc) under anaerobic conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 768:144335. [PMID: 33736299 DOI: 10.1016/j.scitotenv.2020.144335] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 11/18/2020] [Accepted: 12/04/2020] [Indexed: 06/12/2023]
Abstract
The plant pathogen Xanthomonas is commonly found in biocontaminated bioreactors; however, few studies have evaluated the growth and impacts of this microorganism on bioreactors. In this study, we examined the characteristics of Xanthomonas campestris pv. campestris (Xcc). Our results showed that Xcc could reduce metal Fe (III) and decolorise methyl orange in vitro. Moreover, I-t and cyclic voltammetry curves showed that Xcc could generate bioelectricity and had two extracellular electron transfer pathways, similar to that of Shewanella. Based on the spectral analysis of intact cells and scanning electron microscopy analysis, one pathway was speculated to involve cytochrome C by direct contact with the pili or cell surface. The other pathway may involve indirect mediators, such as redox substrates, among extracellular polymeric substances. For the direct extracellular electron transfer process, the charge transfer coefficient α, electron number n, and the electron transfer rate constant ks were determined to be 0.49, 2.6, and 2.2 × 10-3 s-1, respectively. In the indirect extracellular electron transfer processes, the values of α, n, and ks were 0.52, 4, and 1.21 s-1, respectively. Of these two transfer methods, indirect electron transfer is dominant and faster than direct electron transfer. Moreover, after mutation of the dsbD gene, which is important for indirect electron transfer, the electrochemical parameters α, n, and ks decreased. Our findings reveal a new anaerobic mechanism mediating the survival of Xcc during wastewater treatment, and may help develop new strategies for preventing Xcc growth during wastewater treatment.
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Affiliation(s)
- Lei Chen
- School of Life Science, Qufu Normal University, Qufu 273165, China
| | - Mingpeng Wang
- School of Life Science, Qufu Normal University, Qufu 273165, China.
| | - Yujie Feng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Xiaoyu Xu
- School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
| | - Xiaobo Luo
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China
| | - Zhaojie Zhang
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
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30
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Zhang S, Su J, Ali A, Zheng Z, Sun Y. Enhanced denitrification performance of strain YSF15 by different molecular weight of humic acid: Mechanism based on the biological products and activity. BIORESOURCE TECHNOLOGY 2021; 325:124709. [PMID: 33482476 DOI: 10.1016/j.biortech.2021.124709] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/06/2021] [Accepted: 01/08/2021] [Indexed: 06/12/2023]
Abstract
This study aimed to clarify the facilitation by humic acid (HA) fractions (>100, 100-50, 50-30, 30-10, 10-3 and < 3 kDa), as well as their variable effect on denitrification of strain YSF15 under low carbon-nitrogen ratio and nitrate conditions. All HA fractions with 7 mg L-1 were able to accelerate nitrate removal by strain YSF15 and the role of carbon source was inconspicuous. The molecular weight (MW) < 3 kDa was the best promoter for denitrification, with the efficiency (91.32%) far exceeding the control (43.27%), resulting in more stable oxidation-reduction potential, higher nutrients utilization and electron transport activity, more compact protein structure in extracellular polymeric substances and the production of endogenous HA. Each HA fraction could change the bio-products and denitrification activity of strain YSF15. This study sheds light on the facilitation of HA in denitrification from the perspective of MW, implying the potential effect of HA on denitrifying bacteria in community.
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Affiliation(s)
- Shuai Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Junfeng Su
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Amjad Ali
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhijie Zheng
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yi Sun
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
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31
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Yuan Q, Wang S, Wang X, Li N. Biosynthesis of vivianite from microbial extracellular electron transfer and environmental application. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 762:143076. [PMID: 33129535 DOI: 10.1016/j.scitotenv.2020.143076] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/01/2020] [Accepted: 10/11/2020] [Indexed: 06/11/2023]
Abstract
Vivianite (Fe3(PO4)2·8H2O) is a common hydrous ferrous phosphate mineral which often occurs in reductive conditions, especially anoxic non-sulfide environment containing high concentrations of ferrous iron (Fe2+) and orthophosphate (PO43-). Vivianite is an important product of dissimilatory iron reduction and a promising route for phosphorus recovery from wastewater. Its formation is closely related to the extracellular electron transfer (EET), a key mechanism for microbial respiration and a crucial explanation for the reduction of metal oxides in soil and sediments. Despite of the natural ubiquity, easy accessibility and attractive economic value, the application value of vivianite has not received much attention. This review introduces the characteristics, occurrence and biosynthesis of vivianite from microbial EET, and systematically analyzes the application value of vivianite in the environmental field, including immobilization of heavy metals (HMs), dechlorination of carbon tetrachloride (CT), sedimentary phosphorus sequestration and eutrophication alleviation. Additionally, its potential functions as a slow-release fertilizer are discussed as well. In general, vivianite is expected to make more contributions to the future scientific research, especially the solution of environmental problems. Overcoming the lack of understanding and some technical limitations will be beneficial to the further application of vivianite in environmental field.
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Affiliation(s)
- Qing Yuan
- Tianjin Key Lab of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Shu Wang
- Tianjin Key Lab of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Xin Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Nan Li
- Tianjin Key Lab of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin 300072, China.
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32
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Zhang P, Van Cappellen P, Pi K, Yuan S. Oxidation of Fe(II) by Flavins under Anoxic Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11622-11630. [PMID: 32812763 DOI: 10.1021/acs.est.0c02916] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Flavin-mediated electron transfer is an important pathway for Fe(III) reduction by dissimilatory iron-reducing bacteria. Although the mechanisms and kinetics of Fe(III) reduction by reduced flavins have been widely studied, the reaction between Fe(II) and oxidized flavins is rarely investigated. Results of this study show that under anoxic conditions, Fe(II) can be oxidized by the oxidized forms of riboflavin (RBF) and flavin mononucleotide (FMN) at pH 7-9. For instance, at pH 9, 73% of 17.8 μM Fe(II) was oxidized by 10 μM RBF within 20 min. Both the rate and extent of oxidation increased with increasing concentrations of oxidized flavins and increasing solution pH. Thermodynamic calculations and kinetic analyses implied that the oxidation of Fe(II) proceeded predominantly via the autodecomposition of Fe2+-RBF- and Fe2+-FMN- complexes, along with minor contributions from direct oxidation of Fe(II) by flavins and flavin radicals. Our findings suggest that the reoxidation of Fe(II) by oxidized flavins may be a rate-controlling factor in microbial Fe(III) reduction via flavin-mediated electron transfer.
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Affiliation(s)
- Peng Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan, Hubei 430078, P. R. China
| | - Philippe Van Cappellen
- Ecohydrology Research Group, Water Institute and Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Kunfu Pi
- Ecohydrology Research Group, Water Institute and Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Songhu Yuan
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan, Hubei 430078, P. R. China
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Zhang F, Wu JH, Yu HQ. Probing Microbial Extracellular Respiration Ability Using Riboflavin. Anal Chem 2020; 92:10606-10612. [PMID: 32633502 DOI: 10.1021/acs.analchem.0c01650] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Electrochemically active bacteria (EAB) are capable of extracellular electron transfer (EET) to insoluble metal oxides, and thus play a great role in the fields of environment, energy, and geosciences. However, rapid and accurate quantification of the EET ability of EAB is still challenging. In this work, we develop a riboflavin-based fluorescence method for facile, accurate, and in situ measurement of the EET ability of EAB. This method is successfully used to quantify the single-cellular EET ability of Geobacter sulfurreducens DL-1 (60.29 ± 13.02 fA) and Shewanella oneidensis MR-1 (2.11 ± 0.47 fA), the two widely present EAB in the environment. It also enables quantitative identification of EET-related c-type cytochromes in the outer membrane of S. oneidensis MR-1. This method provides a useful tool to rapidly identify EAB in diverse environments and elucidate their electron transfer mechanisms.
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Affiliation(s)
- Feng Zhang
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China.,School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009, China
| | - Jing-Hang Wu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
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Ma H, Gao F, Zhang X, Cui B, Liu Y, Li Z. Formation of iron plaque on roots of Iris pseudacorus and its consequence for cadmium immobilization is impacted by zinc concentration. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 193:110306. [PMID: 32109586 DOI: 10.1016/j.ecoenv.2020.110306] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 01/30/2020] [Accepted: 02/05/2020] [Indexed: 06/10/2023]
Abstract
The impact of iron plaque (IP) on bioavailability of heavy metals to plants has been well documented, but the role of zinc (Zn) in modulating the associated processes remains elusive. We took Iris pseudacorus used in wetland for remediating Cd-contaminated water as an example and systematically studied the combined influence of Cd and Zn concentration on formation of IP and its consequence for immobilization and plant uptake of Cd. The experiment was conducted in hydroponic culture and in each treatment, we measured the physiological traits, activity of antioxidant enzymes (SOD, POD, CAT), mass of the IP, as well as the Cd content in both plant tissues and IP. The results showed that increasing Cd concentration resulted in a steady reduction in IP while the impact of zinc on IP was complicated and appeared to be coupled with Cd. When the Cd concentration was low (0.5 mg L-1 measured as CdCl2 2·5H2O) increasing Zn concentration reduced IP, while when the Cd concentration was increased to 5 mg L-1 increasing zinc concentration led to an increase in IP mass first followed by a decline after Zn concentration exceeded 100 mg L-1 (measured as ZnSO4·7H2O). The change in IP as affected by Zn had a strong consequence for immobilization and plant uptake of Cd. When Cd concentration was low, the IP was comparatively abundant and hence adsorbed most Cd. In contrast, when Cd concentration was high, the IP reduced and the amount of Cd taken up by plant roots and translocated to shoots and leaves increased. Both Cd immobilization and its plant uptake were modulated by Zn concentration. At low Cd concentration the combined Cd immobilized and taken up by plant peaked when the Zn concentration was 50 mg L-1, while at high Cd concentration the combined Cd reached maxima when theZn concentration was 100 mg L-1. The activity of the antioxidant enzymes changed significantly with Zn rather than with Cd. Regardless of Cd concentration, the activity of all three antioxidant enzymes increased first with zinc concentration before declining when the Zn concentration exceeded approximately 100 mg L-1 in all treatments, comparable with the change in immobilization and plant uptake of Cd as the Zn concentration increased. SEM analysis did prove the formation and variation of IP on the root surface of Iris pseudacorus in different treatments. We also found that the plant developed a survival strategy by scarifying its leaves with high Cd content. The results presented in this paper has wide implications as it revealed that care needs to be taken in applying Zn to enhance Cd immobilization and its plant uptake as exceeding the optimal application rate might reduce remediating efficiency rather than increase it.
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Affiliation(s)
- Huanhuan Ma
- Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang, Henan Province, 453002, China.
| | - Feng Gao
- Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang, Henan Province, 453002, China.
| | - Xiaoxian Zhang
- Sustiainable Agriculture Sciences, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom.
| | - Bingjian Cui
- Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang, Henan Province, 453002, China.
| | - Yuan Liu
- Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang, Henan Province, 453002, China.
| | - Zhongyang Li
- Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang, Henan Province, 453002, China.
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Yang Z, Sun T, Subdiaga E, Obst M, Haderlein SB, Maisch M, Kretzschmar R, Angenent LT, Kappler A. Aggregation-dependent electron transfer via redox-active biochar particles stimulate microbial ferrihydrite reduction. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 703:135515. [PMID: 31761354 DOI: 10.1016/j.scitotenv.2019.135515] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/11/2019] [Accepted: 11/12/2019] [Indexed: 06/10/2023]
Abstract
Microbial Fe(III) reduction plays an important role for biogeochemical carbon and iron cycling in sediments and soils. Biochar is used as a soil amendment to increase fertility and lower N2O/CO2 emissions. It is redox-active and can stimulate microbial Fe(III) mineral reduction. It is currently unknown, however, how the aggregation of cells and Fe(III) minerals with biochar particles influence microbial Fe(III) reduction. Therefore, we determined rates and extent of ferrihydrite (Fh) reduction in S. oneidensis MR-1 cell suspensions with different particles sizes of wood-derived Swiss biochar and KonTiki biochar at different biochar/Fh ratios. We found that at small biochar particle size and high biochar/Fh ratios, the biochar, MR-1 cells and Fh closely aggregated, therefore addition of biochar stimulated electron transfer and microbial Fh reduction. In contrast, large biochar particles and low biochar/Fh ratios inhibited the electron transfer and Fe(III) reduction due to the lack of effective aggregation. These results suggest that for stimulating Fh reduction, a certain biochar particle size and biochar/Fh ratio is necessary leading to a close aggregation of all phases. This aggregation favors electron transfer from cells to Fh via redox cycling of the electron donating and accepting functional groups of biochar and via direct electron transfer through conductive biochar carbon matrices. These findings improve our understanding of electron transfer between microorganisms and Fe(III) minerals via redox-active biochar and help to evaluate the impact of biochar on electron transfer processes in the environment.
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Affiliation(s)
- Zhen Yang
- Geomicrobiology, Center for Applied Geoscience, University of Tuebingen, Germany
| | - Tianran Sun
- Environmental Biotechnology, Center for Applied Geoscience, University of Tuebingen, Germany
| | - Edisson Subdiaga
- Environmental Mineralogy and Chemistry, Center for Applied Geoscience, University of Tuebingen, Germany
| | - Martin Obst
- Experimental Biogeochemistry, University of Bayreuth, Germany
| | - Stefan B Haderlein
- Environmental Mineralogy and Chemistry, Center for Applied Geoscience, University of Tuebingen, Germany
| | - Markus Maisch
- Geomicrobiology, Center for Applied Geoscience, University of Tuebingen, Germany
| | - Ruben Kretzschmar
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, CHN, ETH, Zurich, Switzerland
| | - Largus T Angenent
- Environmental Biotechnology, Center for Applied Geoscience, University of Tuebingen, Germany
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geoscience, University of Tuebingen, Germany.
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36
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How does electron transfer occur in microbial fuel cells? World J Microbiol Biotechnol 2020; 36:19. [PMID: 31955250 DOI: 10.1007/s11274-020-2801-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 01/08/2020] [Indexed: 12/16/2022]
Abstract
Microbial fuel cells (MFCs) have emerged as a promising technology for sustainable wastewater treatment coupled with electricity generation. A MFC is a device that uses microbes as catalysts to convert chemical energy present in biomass into electrical energy. Among the various mechanisms that drive the operation of a MFC, extracellular electron transfer (EET) to the anode is one of the most important. Exoelectrogenic bacteria can natively transfer electrons to a conducting surface like the anode. The mechanisms employed for electron transfer can either be direct transfer via conductive pili or nanowires, or mediated transfer that involves either naturally secreted redox mediators like flavins and pyocyanins or artificially added mediators like methylene blue and neutral red. EET is a mechanism wherein microorganisms extract energy for growth and maintenance from their surroundings and transfer the resulting electrons to the anode to generate current. The efficiency of these electron transfer mechanisms is dependent not only on the redox potentials of the species involved, but also on microbial oxidative metabolism that liberates electrons. Attempts at understanding the electron transfer mechanisms will boost efforts in giving rise to practical applications. This article covers the various electron transfer mechanisms involved between microbes and electrodes in microbial fuel cells and their applications.
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Tu Z, de Fátima Silva Lopes H, Igarashi K, Yumoto I. Characterization of the microbiota in long- and short-term natural indigo fermentation. ACTA ACUST UNITED AC 2019; 46:1657-1667. [DOI: 10.1007/s10295-019-02223-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 08/07/2019] [Indexed: 12/12/2022]
Abstract
Abstract
The duration for which the indigo-reducing state maintenance in indigo natural fermentation in batch dependent. The microbiota was analyzed in two batches of sukumo fermentation fluids that lasted for different durations (Batch 1: less than 2 months; Batch 2: nearly 1 year) to understand the mechanisms underlying the sustainability and deterioration of this natural fermentation process. The transformation of the microbiota suggested that the deterioration of the fermentation fluid is associated with the relative abundance of Alcaligenaceae. Principal coordinates analysis (PCoA) showed that the microbial community maintained a very stable state in only the long-term Batch 2. Therefore, entry of the microbiota into a stable state under alkaline anaerobic condition is an important factor for maintenance of indigo fermentation for long duration. This is the first report on the total transformation of the microbiota for investigation of long-term maintenance mechanisms and to address the problem of deterioration in indigo fermentation.
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Affiliation(s)
- Zhihao Tu
- grid.39158.36 0000 0001 2173 7691 Graduate School of Agriculture Hokkaido University Sapporo Japan
- grid.208504.b 0000 0001 2230 7538 Bioproduction Research Institute National Institute of Advanced Industrial Science and Technology Sapporo Japan
| | - Helena de Fátima Silva Lopes
- grid.39158.36 0000 0001 2173 7691 Graduate School of Agriculture Hokkaido University Sapporo Japan
- grid.208504.b 0000 0001 2230 7538 Bioproduction Research Institute National Institute of Advanced Industrial Science and Technology Sapporo Japan
| | - Kensuke Igarashi
- grid.208504.b 0000 0001 2230 7538 Bioproduction Research Institute National Institute of Advanced Industrial Science and Technology Sapporo Japan
| | - Isao Yumoto
- grid.39158.36 0000 0001 2173 7691 Graduate School of Agriculture Hokkaido University Sapporo Japan
- grid.208504.b 0000 0001 2230 7538 Bioproduction Research Institute National Institute of Advanced Industrial Science and Technology Sapporo Japan
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Pi K, Markelova E, Zhang P, Van Cappellen P. Arsenic Oxidation by Flavin-Derived Reactive Species under Oxic and Anoxic Conditions: Oxidant Formation and pH Dependence. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:10897-10905. [PMID: 31419125 DOI: 10.1021/acs.est.9b03188] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Flavins are ubiquitous redox-active compounds capable of producing reactive oxygen (O2•-, •OH, and H2O2) and flavin radical species in natural environments, yet their roles in the redox transformations of environmental contaminants, such as arsenic (As), remain to be investigated. Here, we show that reduced flavins can be a source of effective oxidants for As(III) under both oxic and anoxic conditions. For instance, in the presence of 15 μM reduced riboflavin (RBFH2), 22% of 30 μM As(III) is oxidized in aerated solution at pH 7.0. The co-oxidation of As(III) with RBFH2 is pH-dependent, with a faster reaction rate under mildly acidic relative to alkaline conditions. Quencher tests with 2-propanol (for •OH) and catalase (for H2O2) indicate that As(III) oxidation under oxic conditions is likely controlled by flavin-derived •OH at pH 5.2 and 7.0, and by H2O2 at pH 9.0. Kinetic modeling further implies that flavin-derived reactive oxygen species are mainly responsible for As(III) oxidation under oxic conditions, whereas oxidation of As(III) under anoxic conditions at pH 9.0 is attributed to riboflavin radicals (RBFH•) generated from co-existing oxidized and reduced riboflavin. The demonstrated ability of flavins to catalyze As(III) oxidation has potential implications for As redox cycling in the environment.
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Affiliation(s)
- Kunfu Pi
- Ecohydrology Research Group, Department of Earth and Environmental Sciences & Water Institute , University of Waterloo , N2L 3G1 Waterloo , Canada
| | | | - Peng Zhang
- State Key Laboratory of Biogeology and Environmental Geology , China University of Geosciences , 430074 Wuhan , China
| | - Philippe Van Cappellen
- Ecohydrology Research Group, Department of Earth and Environmental Sciences & Water Institute , University of Waterloo , N2L 3G1 Waterloo , Canada
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Lam BR, Barr CR, Rowe AR, Nealson KH. Differences in Applied Redox Potential on Cathodes Enrich for Diverse Electrochemically Active Microbial Isolates From a Marine Sediment. Front Microbiol 2019; 10:1979. [PMID: 31555224 PMCID: PMC6724507 DOI: 10.3389/fmicb.2019.01979] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 08/12/2019] [Indexed: 01/21/2023] Open
Abstract
The diversity of microbially mediated redox processes that occur in marine sediments is likely underestimated, especially with respect to the metabolisms that involve solid substrate electron donors or acceptors. Though electrochemical studies that utilize poised potential electrodes as a surrogate for solid substrate or mineral interactions have shed some much needed light on these areas, these studies have traditionally been limited to one redox potential or metabolic condition. This work seeks to uncover the diversity of microbes capable of accepting cathodic electrons from a marine sediment utilizing a range of redox potentials, by coupling electrochemical enrichment approaches to microbial cultivation and isolation techniques. Five lab-scale three-electrode electrochemical systems were constructed, using electrodes that were initially incubated in marine sediment at cathodic or electron-donating voltages (five redox potentials between -400 and -750 mV versus Ag/AgCl) as energy sources for enrichment. Electron uptake was monitored in the laboratory bioreactors and linked to the reduction of supplied terminal electron acceptors (nitrate or sulfate). Enriched communities exhibited differences in community structure dependent on poised redox potential and terminal electron acceptor used. Further cultivation of microbes was conducted using media with reduced iron (Fe0, FeCl2) and sulfur (S0) compounds as electron donors, resulting in the isolation of six electrochemically active strains. The isolates belong to the genera Vallitalea of the Clostridia, Arcobacter of the Epsilonproteobacteria, Desulfovibrio of the Deltaproteobacteria, and Vibrio and Marinobacter of the Gammaproteobacteria. Electrochemical characterization of the isolates with cyclic voltammetry yielded a wide range of midpoint potentials (99.20 to -389.1 mV versus Ag/AgCl), indicating diverse metabolic pathways likely support the observed electron uptake. Our work demonstrates culturing under various electrochemical and geochemical regimes allows for enhanced cultivation of diverse cathode-oxidizing microbes from one environmental system. Understanding the mechanisms of solid substrate oxidation from environmental microbes will further elucidation of the ecological relevance of these electron transfer interactions with implications for microbe-electrode technologies.
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Affiliation(s)
- Bonita R. Lam
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
| | - Casey R. Barr
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Annette R. Rowe
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Kenneth H. Nealson
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
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40
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Gurumurthy DM, Bharagava RN, Kumar A, Singh B, Ashfaq M, Saratale GD, Mulla SI. EPS bound flavins driven mediated electron transfer in thermophilic Geobacillus sp. Microbiol Res 2019; 229:126324. [PMID: 31491671 DOI: 10.1016/j.micres.2019.126324] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 08/09/2019] [Accepted: 08/23/2019] [Indexed: 12/23/2022]
Abstract
Through extracellular electron transfer (EET), bacteria are capable of transforming different insoluble materials of geochemical interest into energy-rich molecules for their growth. For this process, bacteria have been depending directly or indirectly on molecules synthesized within the cells or by various synthetics as mediators. Herein, we studied the in-situ change in electrochemistry and supporting components for EET in the extracellular polysaccharide (EPS) producing biofilm of thermophilic Geobacillus sp. The CV and DPV resultsrevealed that the intact biofilm of bacteria was not able to generate any potential at 25 °C /- ≤50 °C. However, at 55 °C (optimal condition), the potential occurred drastically after the EPS production by bacteria. HPLC and MALDI-TOF results revealed that the presence of Flavins, which can able adsorbed to the electrodes from the cell surface. Moreover, the temperature-dependent EPS production and originally conceived ability of flavins to act as electron shuttles suggest that not much complexity in bacteria with minerals. Additionally, the electrochemical potential was severely affected upon removal of EPS/flavin moiety from the intact biofilm, revealed the necessity of EPS bound flavins in transferring the electrons across its thick cell walls. This paradigm shift to electrogenic nature of Geobacillus sp. biofilm will become evident in the adaptation of other microbes during mineral respiration in extreme environments.
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Affiliation(s)
| | - Ram Naresh Bharagava
- Department of Microbiology (DM), School for Environmental Sciences (SES), Babasaheb BhimraoAmbedkar University (A Central University), VidyaVihar, Raebareli Road, Lucknow 226 025, Uttar Pradesh, India
| | - Ashok Kumar
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh, 173234, India
| | - Bhaskar Singh
- Department of Environmental Sciences, Central University of Jharkhand, Ranchi, 835205, Jharkhand, India
| | - Muhammad Ashfaq
- Department of Chemistry, University of Gujrat, Gujrat, 50700, Pakistan
| | - Ganesh Dattatraya Saratale
- Department of Food Science and Biotechnology, Dongguk University-Seoul, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Sikandar I Mulla
- Department of Biochemistry, School of Applied Sciences, REVA University, Bangalore, 560 064, Karnataka State, India.
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Analysis of the microbiota involved in the early changes associated with indigo reduction in the natural fermentation of indigo. World J Microbiol Biotechnol 2019; 35:123. [DOI: 10.1007/s11274-019-2699-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/17/2019] [Indexed: 01/01/2023]
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42
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Dissimilatory reduction of Fe(III) by a novel Serratia marcescens strain with special insight into the influence of prodigiosin. Int Microbiol 2019; 23:201-214. [DOI: 10.1007/s10123-019-00088-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 06/12/2019] [Accepted: 06/14/2019] [Indexed: 12/21/2022]
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43
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Zhao G, Li E, Li J, Liu F, Yang X, Xu M. Effects of Flavin-Goethite Interaction on Goethite Reduction by Shewanella decolorationis S12. Front Microbiol 2019; 10:1623. [PMID: 31379778 PMCID: PMC6657588 DOI: 10.3389/fmicb.2019.01623] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 07/01/2019] [Indexed: 11/13/2022] Open
Abstract
Flavin mononucleotide (FMN) and riboflavin are structurally similar flavins, except for the presence of a phosphate group on the FMN molecule. They are used by a variety of electroactive bacteria as extracellular electron shuttles in microbial Fe reduction and inevitably interact with Fe (hydr)oxides in the extracellular environment. It is currently unknown whether flavin/Fe (hydr)oxide interaction interferes with extracellular electron transfer (EET) to the mineral surface. In this study, we found that the goethite reduction rate was lower when mediated by FMN than by RF, suggesting that FMN was less effective in shuttling electrons between cells and minerals. Nevertheless, the phosphate group did not prevent the FMN molecule from accepting electrons from bacterial cells and transferring electrons to the mineral. Results of adsorption experiment, attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy, and bacterial attachment trend analyses showed that FMN exhibited strong adsorption on goethite surface by forming phosphate inner-sphere complex, which prevented bacterial cells from approaching goethite. Therefore, the interaction between FMN and goethite surface may increase the distance of electron transfer from bacterial cells to goethite and result in lower EET efficiency in comparison to those mediated by riboflavin. To our knowledge, these data reveal for the first time that the interaction between flavin and Fe (hydr)oxide affect flavin-mediated electron transfer to mineral surface and add a new dimension to our understanding of flavin-mediated microbial Fe reduction processes.
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Affiliation(s)
- Gang Zhao
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Enze Li
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Jianjun Li
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Fei Liu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Xunan Yang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Meiying Xu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
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Tokunou Y, Okamoto A. Geometrical Changes in the Hemes of Bacterial Surface c-Type Cytochromes Reveal Flexibility in Their Binding Affinity with Minerals. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:7529-7537. [PMID: 30351954 DOI: 10.1021/acs.langmuir.8b02977] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Microbial extracellular electron transport occurs via the physical and electrical association of outer-membrane c-type cytochromes (OM c-Cyts) with extracellular solid surfaces. However, studies investigating the characteristics of cytochrome binding with solid materials have been limited to the use of purified units of OM c-Cyts dissolved in solution, rather than OM c-Cyts in intact cells, because of the lack of a methodology that specifically allows for the monitoring of OM c-Cyts in whole-cells. Here, we utilized circular dichroism (CD) spectroscopy to examine the molecular mechanisms and binding characteristics of the interaction between MtrC, a unit of OM c-Cyts, in whole Shewanella oneidensis MR-1 cells and hematite nanoparticles. The addition of hematite nanoparticles significantly decreased the intensity of the Soret CD peaks, indicating geometrical changes in the hemes in MtrC associated with their physical contact with hematite. The binding affinity of MtrC estimated using CD spectra changed predominantly depending upon the redox state of MtrC and the concentration of the hematite nanoparticles. In contrast, purified MtrC demonstrated a constant binding affinity following a Langmuir isotherm, with a standard Gibbs free energy of -43 kJ mol-1, suggesting that the flexibility in the binding affinity of MtrC with hematite was specific in membrane-bound protein complex conditions. Overall, these findings suggest that the binding affinity as well as the heme geometry of OM c-Cyts are flexibly modulated in the membrane complex associated with microbe-mineral interactions.
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Affiliation(s)
- Yoshihide Tokunou
- Department of Applied Chemistry , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-8656 , Japan
- International Center for Materials Nanoarchitectonics , National Institute for Materials Science , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan
| | - Akihiro Okamoto
- International Center for Materials Nanoarchitectonics , National Institute for Materials Science , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan
- Center for Functional Sensor & Actuator , National Institute for Materials Science , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan
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45
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Extracellular electron transfer features of Gram-positive bacteria. Anal Chim Acta 2019; 1076:32-47. [PMID: 31203962 DOI: 10.1016/j.aca.2019.05.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/23/2019] [Accepted: 05/05/2019] [Indexed: 12/20/2022]
Abstract
Electroactive microorganisms possess the unique ability to transfer electrons to or from solid phase electron conductors, e.g., electrodes or minerals, through various physiological mechanisms. The processes are commonly known as extracellular electron transfer and broadly harnessed in microbial electrochemical systems, such as microbial biosensors, microbial electrosynthesis, or microbial fuel cells. Apart from a few model microorganisms, the nature of the microbe-electrode conductive interaction is poorly understood for most of the electroactive species. The interaction determines the efficiency and a potential scaling up of bioelectrochemical systems. Gram-positive bacteria generally have a thick electron non-conductive cell wall and are believed to exhibit weak extracellular electron shuttling activity. This review highlights reported research accomplishments on electroactive Gram-positive bacteria. The use of electron-conducting polymers as mediators is considered as one promising strategy to enhance the electron transfer efficiency up to application scale. In view of the recent progress in understanding the molecular aspects of the extracellular electron transfer mechanisms of Enterococcus faecalis, the electron transfer properties of this bacterium are especially focused on. Fundamental knowledge on the nature of microbial extracellular electron transfer and its possibilities can provide insight in interspecies electron transfer and biogeochemical cycling of elements in nature. Additionally, a comprehensive understanding of cell-electrode interactions may help in overcoming insufficient electron transfer and restricted operational performance of various bioelectrochemical systems and facilitate their practical applications.
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Xu J, Yin Y, Tan Z, Wang B, Guo X, Li X, Liu J. Enhanced removal of Cr(VI) by biochar with Fe as electron shuttles. J Environ Sci (China) 2019; 78:109-117. [PMID: 30665629 DOI: 10.1016/j.jes.2018.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 06/11/2018] [Accepted: 07/17/2018] [Indexed: 06/09/2023]
Abstract
Biochar is extensively used as an effective soil amendment for environmental remediation. In addition to its strong contaminant sorption capability, biochar also plays an important role in chemical transformation of contaminant due to its inherent redox-active moieties. However, the transformation efficiency of inorganic contaminants is generally very limited when the direct adsorption of contaminants on biochar is inefficient. The present study demonstrates the role of Fe ion as an electron shuttle to enhance Cr(VI) reduction by biochars. Batch experiments were conducted to examine the effects of Fe(III) levels, pyrolysis temperature of biochar, initial solution pH, and biochar dosage on the efficiency of Cr(VI) removal. Results showed a significant enhancement in Cr(VI) reduction with an increase in Fe(III) concentration and a decrease of initial pH. Biochar produced at higher pyrolysis temperatures (e.g., 700°C) favored Cr(VI) removal, especially in the presence of Fe(III), while a higher biochar dosage proved unfavorable likely due to the agglomeration or precipitation of biochar. Speciation analysis of Fe and Cr elements on the surface of biochar and in the solution further confirmed the role of Fe ion as an electron shuttle between biochar and Cr(VI). The present findings provide a potential strategy for the advanced treatment of Cr(VI) at low concentrations as well as an insight into the environmental fate of Cr(VI) and other micro-pollutants in soil or aqueous compartments containing Fe and natural or engineered carbonaceous materials.
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Affiliation(s)
- Jingwen Xu
- School of Environmental Sciences, Liaoning University, Shenyang, Liaoning 110036, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yongguang Yin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Zhiqiang Tan
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Bowen Wang
- School of Environmental Sciences, Liaoning University, Shenyang, Liaoning 110036, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xiaoru Guo
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xia Li
- School of Environmental Sciences, Liaoning University, Shenyang, Liaoning 110036, China.
| | - Jingfu Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Microbial diversity involved in iron and cryptic sulfur cycling in the ferruginous, low-sulfate waters of Lake Pavin. PLoS One 2019; 14:e0212787. [PMID: 30794698 PMCID: PMC6386445 DOI: 10.1371/journal.pone.0212787] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 02/08/2019] [Indexed: 11/19/2022] Open
Abstract
Both iron- and sulfur- reducing bacteria strongly impact the mineralogy of iron, but their activity has long been thought to be spatially and temporally segregated based on the higher thermodynamic yields of iron over sulfate reduction. However, recent evidence suggests that sulfur cycling can predominate even under ferruginous conditions. In this study, we investigated the potential for bacterial iron and sulfur metabolisms in the iron-rich (1.2 mM dissolved Fe2+), sulfate-poor (< 20 μM) Lake Pavin which is expected to host large populations of iron-reducing and iron-oxidizing microorganisms influencing the mineralogy of iron precipitates in its permanently anoxic bottom waters and sediments. 16S rRNA gene amplicon libraries from at and below the oxycline revealed that highly diverse populations of sulfur/sulfate-reducing (SRB) and sulfur/sulfide-oxidizing bacteria represented up to 10% and 5% of the total recovered sequences in situ, respectively, which together was roughly equivalent to the fraction of putative iron cycling bacteria. In enrichment cultures amended with key iron phases identified in situ (ferric iron phosphate, ferrihydrite) or with soluble iron (Fe2+), SRB were the most competitive microorganisms, both in the presence and absence of added sulfate. The large fraction of Sulfurospirillum, which are known to reduce thiosulfate and sulfur but not sulfate, present in all cultures was likely supported by Fe(III)-driven sulfide oxidation. These results support the hypothesis that an active cryptic sulfur cycle interacts with iron cycling in the lake. Analyses of mineral phases showed that ferric phosphate in cultures dominated by SRB was transformed to vivianite with concomitant precipitation of iron sulfides. As colloidal FeS and vivianite have been reported in the monimolimnion, we suggest that SRB along with iron-reducing bacteria strongly influence iron mineralogy in the water column and sediments of Lake Pavin.
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Aromokeye DA, Richter-Heitmann T, Oni OE, Kulkarni A, Yin X, Kasten S, Friedrich MW. Temperature Controls Crystalline Iron Oxide Utilization by Microbial Communities in Methanic Ferruginous Marine Sediment Incubations. Front Microbiol 2018; 9:2574. [PMID: 30425692 PMCID: PMC6218420 DOI: 10.3389/fmicb.2018.02574] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 10/09/2018] [Indexed: 11/13/2022] Open
Abstract
Microorganisms can use crystalline iron minerals for iron reduction linked to organic matter degradation or as conduits for direct interspecies electron transfer (mDIET) to syntrophic partners, e.g., methanogens. The environmental conditions that lead either to reduction or conduit use are so far unknown. We investigated microbial community shifts and interactions with crystalline iron minerals (hematite and magnetite) in methanic ferruginous marine sediment incubations during organic matter (glucose) degradation at varying temperatures. Iron reduction rates increased with decreasing temperature from 30°C to 4°C. Both hematite and magnetite facilitated iron reduction at 4°C, demonstrating that microorganisms in the methanic zone of marine sediments can reduce crystalline iron oxides under psychrophilic conditions. Methanogenesis occurred, however, at higher rates with increasing temperature. At 30°C, both hematite and magnetite accelerated methanogenesis onset and maximum process rates. At lower temperatures (10°C and 4°C), hematite could still facilitate methanogenesis but magnetite served more as an electron acceptor for iron reduction than as a conduit. Different temperatures selected for different key microorganisms: at 30°C, members of genus Orenia, Halobacteroidaceae, at 10°C, Photobacterium and the order Clostridiales, and at 4°C Photobacterium and Psychromonas were enriched. Members of the order Desulfuromonadales harboring known dissimilatory iron reducers were also enriched at all temperatures. Our results show that crystalline iron oxides predominant in some natural environments can facilitate electron transfer between microbial communities at psychrophilic temperatures. Furthermore, temperature has a critical role in determining the pathway of crystalline iron oxide utilization in marine sediment shifting from conduction at 30°C to predominantly iron reduction at lower temperatures.
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Affiliation(s)
- David A Aromokeye
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany.,MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.,International Max Planck Research School for Marine Microbiology, Max-Planck-Institute for Marine Microbiology, Bremen, Germany
| | - Tim Richter-Heitmann
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany
| | - Oluwatobi E Oni
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany.,MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Ajinkya Kulkarni
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany.,MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.,International Max Planck Research School for Marine Microbiology, Max-Planck-Institute for Marine Microbiology, Bremen, Germany
| | - Xiuran Yin
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany.,MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.,International Max Planck Research School for Marine Microbiology, Max-Planck-Institute for Marine Microbiology, Bremen, Germany
| | - Sabine Kasten
- MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.,Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany.,Faculty of Geosciences, University of Bremen, Bremen, Germany
| | - Michael W Friedrich
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany.,MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
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Zou L, Qiao Y, Li CM. Boosting Microbial Electrocatalytic Kinetics for High Power Density: Insights into Synthetic Biology and Advanced Nanoscience. ELECTROCHEM ENERGY R 2018. [DOI: 10.1007/s41918-018-0020-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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50
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Aino K, Hirota K, Okamoto T, Tu Z, Matsuyama H, Yumoto I. Microbial Communities Associated With Indigo Fermentation That Thrive in Anaerobic Alkaline Environments. Front Microbiol 2018; 9:2196. [PMID: 30279681 PMCID: PMC6153312 DOI: 10.3389/fmicb.2018.02196] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 08/28/2018] [Indexed: 12/31/2022] Open
Abstract
Indigo fermentation, which depends on the indigo-reducing action of microorganisms, has traditionally been performed to dye textiles blue in Asia as well as in Europe. This fermentation process is carried out by naturally occurring microbial communities and occurs under alkaline, anaerobic conditions. Therefore, there is uncertainty regarding the fermentation process, and many unknown microorganisms thrive in this unique fermentation environment. Until recently, there was limited information available on bacteria associated with this fermentation process. Indigo reduction normally occurs from 4 days to 2 weeks after initiation of fermentation. However, the changes in the microbiota that occur during the transition to an indigo-reducing state have not been elucidated. Here, the structural changes in the bacterial community were estimated by PCR-based methods. On the second day of fermentation, a large change in the redox potential occurred. On the fourth day, distinct substitution of the genus Halomonas with the aerotolerant genus Amphibacillus was observed, corresponding to marked changes in indigo reduction. Under open-air conditions, indigo reduction during the fermentation process continued for 6 months on average. The microbiota, including indigo-reducing bacteria, was continuously replaced with other microbial communities that consisted of other types of indigo-reducing bacteria. A stable state consisting mainly of the genus Anaerobacillus was also observed in a long-term fermentation sample. The stability of the microbiota, proportion of indigo-reducing microorganisms, and appropriate diversity and microbiota within the fluid may play key factors in the maintenance of a reducing state during long-term indigo fermentation. Although more than 10 species of indigo-reducing bacteria were identified, the reduction mechanism of indigo particle is riddle. It can be predicted that the mechanism involves electrons, as byproducts of metabolism, being discarded by analogs mechanisms reported in bacterial extracellular solid Fe3+ reduction under alkaline anaerobic condition.
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Affiliation(s)
- Keiichi Aino
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Sapporo, Japan
- Department of Bioscience and Technology, School of Biological Science and Engineering, Tokai University, Hiratsuka-shi, Japan
| | - Kikue Hirota
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Sapporo, Japan
| | - Takahiro Okamoto
- Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Zhihao Tu
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Sapporo, Japan
- Department of Bioscience and Technology, School of Biological Science and Engineering, Tokai University, Hiratsuka-shi, Japan
| | | | - Isao Yumoto
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Sapporo, Japan
- Department of Bioscience and Technology, School of Biological Science and Engineering, Tokai University, Hiratsuka-shi, Japan
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