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Guo J, Wang XY, Li T, Gao MT, Hu J, Li J. Effect of micro-nanobubbles with different gas sources on the growth and metabolism of chemoautotrophic microorganisms. Process Biochem 2022. [DOI: 10.1016/j.procbio.2022.12.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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2
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Sackett JD, Kamble N, Leach E, Schuelke T, Wilbanks E, Rowe AR. Genome-Scale Mutational Analysis of Cathode-Oxidizing Thioclava electrotropha ElOx9 T. Front Microbiol 2022; 13:909824. [PMID: 35756027 PMCID: PMC9226611 DOI: 10.3389/fmicb.2022.909824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/17/2022] [Indexed: 11/13/2022] Open
Abstract
Extracellular electron transfer (EET) – the process by which microorganisms transfer electrons across their membrane(s) to/from solid-phase materials – has implications for a wide range of biogeochemically important processes in marine environments. Though EET is thought to play an important role in the oxidation of inorganic minerals by lithotrophic organisms, the mechanisms involved in the oxidation of solid particles are poorly understood. To explore the genetic basis of oxidative EET, we utilized genomic analyses and transposon insertion mutagenesis screens (Tn-seq) in the metabolically flexible, lithotrophic Alphaproteobacterium Thioclava electrotropha ElOx9T. The finished genome of this strain is 4.3 MB, and consists of 4,139 predicted ORFs, 54 contain heme binding motifs, and 33 of those 54 are predicted to localize to the cell envelope or have unknown localizations. To begin to understand the genetic basis of oxidative EET in ElOx9T, we constructed a transposon mutant library in semi-rich media which was comprised of >91,000 individual mutants encompassing >69,000 unique TA dinucleotide insertion sites. The library was subjected to heterotrophic growth on minimal media with acetate and autotrophic oxidative EET conditions on indium tin oxide coated glass electrodes poised at –278 mV vs. SHE or un-poised in an open circuit condition. We identified 528 genes classified as essential under these growth conditions. With respect to electrochemical conditions, 25 genes were essential under oxidative EET conditions, and 29 genes were essential in both the open circuit control and oxidative EET conditions. Though many of the genes identified under electrochemical conditions are predicted to be localized in the cytoplasm and lack heme binding motifs and/or homology to known EET proteins, we identified several hypothetical proteins and poorly characterized oxidoreductases that implicate a novel mechanism(s) for EET that warrants further study. Our results provide a starting point to explore the genetic basis of novel oxidative EET in this marine sediment microbe.
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Affiliation(s)
- Joshua D Sackett
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Nitin Kamble
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Edmund Leach
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Taruna Schuelke
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Elizabeth Wilbanks
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Annette R Rowe
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
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3
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Hu Y, Chen J, Wang C, Wang P, Gao H, Zhang J, Zhang B, Cui G, Zhao D. Insight into microbial degradation of hexabromocyclododecane (HBCD) in lake sediments under different hydrodynamic conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 827:154358. [PMID: 35259383 DOI: 10.1016/j.scitotenv.2022.154358] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 02/24/2022] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
Hexabromocyclododecane (HBCD), an emerging persistent organic pollutant, has been widely detected in aquatic ecosystems with various hydrodynamic conditions, however, the effects of hydrodynamic changes on microbial degradation of HBCD in aquatic sediment remains unclear. Here, we conducted an annular flume experiment to characterize variation in HBCD removal from contaminated sediment under three hydrodynamic conditions with different flow velocities, as well as clarify the underlying microbial mechanisms. We detected significant HBCD removal and bromine ion generation in all contaminated sediments, and microbial reduction debromination was an important process for HBCD removal. At the end of the 49-day experiment, both HBCD removal percentage and the bromine ion concentration were significantly lower under dynamic water condition with higher sediment redox potential, compared with static water conditions. The dynamic water conditions resulted a relatively high sediment redox potential and decreased the iron reduction rate and the abundance of organohalide-respiring bacteria (OHRB) in the genera Geobatcer, Dehalogenimonas, Dehalobacter, and Dehalococcoide, which reduced the microbial degradation of HBCD in contaminated sediments. The community composition of both total bacteria and OHRB also differed significantly among hydrodynamic conditions. Some bacterial groups with HBCD degradation abilities such as Pseudomonas and Sulfuricurvum were less abundant under dynamic water conditions, and the HBCD degradation efficiencies were lower. These findings enhance our understanding of the bioremediation potential of HBCD-contaminated sediments in different hydrodynamic areas.
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Affiliation(s)
- Yu Hu
- Key Laboratory of Integrated Regulation and Resource Department on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, 1 Xikang Road, Nanjing 210098, PR China
| | - Juan Chen
- Key Laboratory of Integrated Regulation and Resource Department on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, 1 Xikang Road, Nanjing 210098, PR China.
| | - Chao Wang
- Key Laboratory of Integrated Regulation and Resource Department on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, 1 Xikang Road, Nanjing 210098, PR China
| | - Peifang Wang
- Key Laboratory of Integrated Regulation and Resource Department on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, 1 Xikang Road, Nanjing 210098, PR China
| | - Han Gao
- Key Laboratory of Integrated Regulation and Resource Department on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, 1 Xikang Road, Nanjing 210098, PR China
| | - Jingjing Zhang
- Key Laboratory of Integrated Regulation and Resource Department on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, 1 Xikang Road, Nanjing 210098, PR China
| | - Bo Zhang
- Key Laboratory of Integrated Regulation and Resource Department on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, 1 Xikang Road, Nanjing 210098, PR China
| | - Ge Cui
- Key Laboratory of Integrated Regulation and Resource Department on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, 1 Xikang Road, Nanjing 210098, PR China
| | - Dan Zhao
- Kunming Engineering Corporation Limited, Power China, 115 People's East Road, Kunming 650216, PR China
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Zhang L, Yan C, Wang D, Zhen Z. Spatiotemporal dynamic changes of antibiotic resistance genes in constructed wetlands and associated influencing factors. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 303:119176. [PMID: 35306086 DOI: 10.1016/j.envpol.2022.119176] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 02/21/2022] [Accepted: 03/15/2022] [Indexed: 06/14/2023]
Abstract
A better understanding of the spatiotemporal dynamics and influencing factors of sulfonamide antibiotic resistance genes (ARGs) distribution in subsurface flow constructed wetlands is essential to improve the ARGs removal efficiency. The spatiotemporal dynamics of sulfonamide ARGs were explored in the vertical upflow subsurface flow constructed wetland (VUSFCW). The results showed that the absolute abundance of ARGs presented a trend of bottom layer > middle layer > top layer. The relative abundance of ARGs decreased significantly from the bottom layer to the middle layer, but increased in the top layer. The bottom layer was the main stage to remove ARGs. The absolute abundance of ARGs at each point in summer was significantly higher than that in winter. Based on the spatiotemporal distribution of ARGs, the internal mechanism of ARGs dynamic change was explored by the partial least square path analysis model. The results showed that physical-chemical factors, microorganisms and antibiotics indirectly affected the spatiotemporal distribution of ARGs mainly through mobile genetic elements. The indirect influence coefficients of physical-chemical factors, microorganisms and antibiotics on the spatiotemporal distribution of ARGs were 0.505, 0.221 and 0.98 respectively. The direct influence coefficient of MGEs on the spatiotemporal distribution of ARGs was 0.895. The results of network analysis showed that the potential host species of ARGs in summer were more abundant than those in winter. The selection mode of sulfonamide ARGs to potential hosts was nonspecific. There is a risk of sulfonamide ARGs infecting pathogens in VUSFCW. Fortunately, VUSFCW has proven effective in reducing the absolute abundance of ARGs and the potential risk of pathogens carrying ARGs. These findings provide a model simulation and theoretical basis for effectively reducing the threat of ARGs.
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Affiliation(s)
- Ling Zhang
- Key Laboratory of Urban Environment and Health, Fujian Key Laboratory of Watershed Ecology, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Changzhou Yan
- Key Laboratory of Urban Environment and Health, Fujian Key Laboratory of Watershed Ecology, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
| | - Dapeng Wang
- Key Laboratory of Urban Environment and Health, Fujian Key Laboratory of Watershed Ecology, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | - Zhuo Zhen
- Key Laboratory of Urban Environment and Health, Fujian Key Laboratory of Watershed Ecology, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
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5
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Tian L, Yan X, Wang D, Du Q, Wan Y, Zhou L, Li T, Liao C, Li N, Wang X. Two key Geobacter species of wastewater-enriched electroactive biofilm respond differently to electric field. WATER RESEARCH 2022; 213:118185. [PMID: 35183018 DOI: 10.1016/j.watres.2022.118185] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/10/2022] [Accepted: 02/11/2022] [Indexed: 06/14/2023]
Abstract
Electroactive biofilms have attracted increasing attention due to their unique ability to exchange electrons with electrodes. Geobacter spp. are widely found to be dominant in biofilms in acetate-rich environments when an appropriate voltage is applied, but it is still largely unknown how these bacteria are selectively enriched. Herein, two key Geobacter spp. that have been demonstrated predominant in wastewater-enriched electroactive biofilm after long-term operation, G. sulfurreducens and G. anodireducens, responded to electric field (EF) differently, leading to a higher abundance of EF-sensitive G. anodireducens in the strong EF region after cocultivation with G. sulfurreducens. Transcriptome analysis indicated that two-component systems containing sensor histidine kinases and response regulators were the key for EF sensing in G. anodireducens rather than in G. sulfurreducens, which are closely connected to chemotaxis, c-di-GMP, fatty acid metabolism, pilus, oxidative phosphorylation and transcription, resulting in an increase in extracellular polymeric substance secretion and rapid cell proliferation. Our data reveal the mechanism by which EF select specific Geobacter spp. over time, providing new insights into Geobacter biofilm formation regulated by electricity.
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Affiliation(s)
- Lili Tian
- MOE Key Laboratory of Pollution Processes and Environmental Criteria / Tianjin Key Laboratory of Environmental Remediation and Pollution Control / College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Xuejun Yan
- MOE Key Laboratory of Pollution Processes and Environmental Criteria / Tianjin Key Laboratory of Environmental Remediation and Pollution Control / College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Dongbin Wang
- School of Public Health, Guangdong Medical University, Xincheng Road, Dongguan 523000, China
| | - Qing Du
- School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China
| | - Yuxuan Wan
- MOE Key Laboratory of Pollution Processes and Environmental Criteria / Tianjin Key Laboratory of Environmental Remediation and Pollution Control / College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Lean Zhou
- School of Hydraulic Engineering, Changsha University of Science and Technology, Changsha 410114, China
| | - Tian Li
- MOE Key Laboratory of Pollution Processes and Environmental Criteria / Tianjin Key Laboratory of Environmental Remediation and Pollution Control / College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Chengmei Liao
- MOE Key Laboratory of Pollution Processes and Environmental Criteria / Tianjin Key Laboratory of Environmental Remediation and Pollution Control / College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Nan Li
- School of Environmental Science and Engineering, Tianjin University, No. 35 Yaguan Road, Jinnan District, Tianjin 300350, China
| | - Xin Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria / Tianjin Key Laboratory of Environmental Remediation and Pollution Control / College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China.
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6
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Zhang L, Yan C, Qi R, Yang F. Quantifying the contribution rates of sulfonamide antibiotics removal mechanisms in constructed wetlands using multivariate statistical analysis. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 292:118463. [PMID: 34742821 DOI: 10.1016/j.envpol.2021.118463] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 10/26/2021] [Accepted: 11/02/2021] [Indexed: 06/13/2023]
Abstract
The removal of antibiotics in subsurface flow constructed wetlands is performed through various removal mechanisms, such as adsorption, hydrolysis, microbial degradation and plant uptake. However, the contribution rates of the removal mechanisms in constructed wetlands are still not well studied. This study conducted a series of experiments and used multivariate statistical analysis to determine contribution rates for substrate adsorption, hydrolysis, and microbial degradation. Multiple stepwise regression analysis indicated that specific surface area and salt content were the main factors influencing sulfonamide adsorption, while temperature and pH were the main factors influencing sulfonamide hydrolysis. Variance partitioning analysis showed that the influence of physical-chemical factors was greater than that of nutrients on the microbial community. Partial least squares path analysis showed that the path coefficients of microbial degradation, adsorption and hydrolysis for sulfonamides removal in vertical subsurface flow constructed wetlands were 0.6339, 0.3608 and 0.0351, respectively, while the corresponding path coefficient were 0.5658, 0.4707 and 0.1079 in horizontal subsurface flow constructed wetlands, respectively. This means that microbial degradation contributes the most to the removal of sulfonamides in subsurface flow constructed wetlands. Enhanced microbial degradation may be a powerful measure to improve the removal of sulfonamides. These results will be helpful for understanding the removal mechanism of antibiotics and will provide a definite direction for pertinently improving sulfonamide removal efficiency in constructed wetlands.
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Affiliation(s)
- Ling Zhang
- Key Laboratory of Urban Environment and Health, Fujian Key Laboratory of Watershed Ecology, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Changzhou Yan
- Key Laboratory of Urban Environment and Health, Fujian Key Laboratory of Watershed Ecology, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
| | - Ran Qi
- Key Laboratory of Urban Environment and Health, Fujian Key Laboratory of Watershed Ecology, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fan Yang
- Key Laboratory of Urban Environment and Health, Fujian Key Laboratory of Watershed Ecology, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
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7
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Li XM, Ding LJ, Zhu D, Zhu YG. Long-Term Fertilization Shapes the Putative Electrotrophic Microbial Community in Paddy Soils Revealed by Microbial Electrosynthesis Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:3430-3441. [PMID: 33600162 DOI: 10.1021/acs.est.0c08022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Electrotrophs play an important role in biogeochemical cycles, but the effects of long-term fertilization on electrotrophic communities in paddy soils remain unclear. Here, we explored the responses of electrotrophic communities in paddy soil-based microcosms to different long-term fertilization practices using microbial electrosynthesis systems (MESs), high-throughput quantitative PCR, and 16s rRNA gene-based Illumina sequencing techniques. Compared to the case in the unfertilized soil (CK), applications of only manure (M); only chemical nitrogen, phosphorous, and potassium fertilizers (NPK); and M plus NPK (MNPK) clearly changed the electrotrophic bacterial community structure. The Streptomyces genus of the Actinobacteria phylum was the dominant electrotroph in the CK, M, and MNPK soils. The latter two soils also favored Truepera of Deinococcus-Thermus or Arenimonas and Thioalkalispira of Proteobacteria. Furthermore, Pseudomonas of Proteobacteria and Bacillus of Firmicutes were major electrotrophs in the NPK soil. These electrotrophs consumed biocathodic currents coupled with nitrate reduction and recovered 18-38% of electrons via dissimilatory nitrate reduction to ammonium (DNRA). The increased abundances of the nrfA gene for DNRA induced by electrical potential further supported that the electrotrophs enhanced DNRA for all soils. These expand our knowledge about the diversity of electrotrophs and their roles in N cycle in paddy soils and highlight the importance of fertilization in shaping electrotrophic communities.
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Affiliation(s)
- Xiao-Min Li
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, No. 18, Haidian District, Beijing 100085, China
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Jimei Road, No. 1799, Jimei District, Xiamen 361021, China
- Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo Urban Environment Observation and Research Station, Chinese Academy of Sciences, Zhongke Road 88, Beilun District, Ningbo 315830, China
- University of Chinese Academy of Sciences, Yuquan Road, No. 19A, Shijingshan District, Beijing 100049, China
| | - Long-Jun Ding
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, No. 18, Haidian District, Beijing 100085, China
| | - Dong Zhu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, No. 18, Haidian District, Beijing 100085, China
| | - Yong-Guan Zhu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, No. 18, Haidian District, Beijing 100085, China
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Jimei Road, No. 1799, Jimei District, Xiamen 361021, China
- University of Chinese Academy of Sciences, Yuquan Road, No. 19A, Shijingshan District, Beijing 100049, China
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8
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Yang X, Chen S. Microorganisms in sediment microbial fuel cells: Ecological niche, microbial response, and environmental function. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 756:144145. [PMID: 33303196 DOI: 10.1016/j.scitotenv.2020.144145] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/05/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
A sediment microbial fuel cell (SMFC) is a device that harvests electrical energy from sediments rich in organic matter. SMFCs have been attracting increasing amounts of interest in environmental remediation, since they are capable of providing a clean and inexhaustible source of electron donors or acceptors and can be easily controlled by adjusting the electrochemical parameters. The microorganisms inhabiting sediments and the overlying water play a pivotal role in SMFCs. Since the SMFC is applied in an open environment rather than in an enclosed chamber, the effects of the environment on the microbes should be intense and the microbial community succession should be extremely complex. Thus, this review aims to provide an overview of the microorganisms in SMFCs, which few previous review papers have reported. In this study, the anodic and cathodic niches for the microorganisms in SMFCs are summarized, how the microbial population and community interact with the SMFC environment is discussed, a new microbial succession strategy called the electrode stimulation succession is proposed, and recent developments in the environmental functions of SMFCs are discussed from the perspective of microorganisms. Future studies are needed to investigate the electrode stimulation succession, the environmental function and the electron transfer mechanism in order to boost the application of SMFCs for power generation and environmental remediation.
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Affiliation(s)
- Xunan Yang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China.
| | - Shanshan Chen
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China.
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9
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Gupta D, Guzman MS, Bose A. Extracellular electron uptake by autotrophic microbes: physiological, ecological, and evolutionary implications. ACTA ACUST UNITED AC 2020; 47:863-876. [DOI: 10.1007/s10295-020-02309-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/07/2020] [Indexed: 02/05/2023]
Abstract
Abstract
Microbes exchange electrons with their extracellular environment via direct or indirect means. This exchange is bidirectional and supports essential microbial oxidation–reduction processes, such as respiration and photosynthesis. The microbial capacity to use electrons from insoluble electron donors, such as redox-active minerals, poised electrodes, or even other microbial cells is called extracellular electron uptake (EEU). Autotrophs with this capability can thrive in nutrient and soluble electron donor-deficient environments. As primary producers, autotrophic microbes capable of EEU greatly impact microbial ecology and play important roles in matter and energy flow in the biosphere. In this review, we discuss EEU-driven autotrophic metabolisms, their mechanism and physiology, and highlight their ecological, evolutionary, and biotechnological implications.
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Affiliation(s)
- Dinesh Gupta
- grid.4367.6 0000 0001 2355 7002 Department of Biology Washington University in St. Louis One Brookings Drive 63130 St. Louis MO USA
| | - Michael S Guzman
- grid.250008.f 0000 0001 2160 9702 Biosciences and Biotechnology Division Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory Livermore CA USA
| | - Arpita Bose
- grid.4367.6 0000 0001 2355 7002 Department of Biology Washington University in St. Louis One Brookings Drive 63130 St. Louis MO USA
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10
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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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11
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Jiang Y, Chu N, Zhang W, Ma J, Zhang F, Liang P, Zeng RJ. Zinc: A promising material for electrocatalyst-assisted microbial electrosynthesis of carboxylic acids from carbon dioxide. WATER RESEARCH 2019; 159:87-94. [PMID: 31078755 DOI: 10.1016/j.watres.2019.04.053] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 04/26/2019] [Accepted: 04/28/2019] [Indexed: 06/09/2023]
Abstract
Microbial electrosynthesis (MES) has been proposed as a sustainable platform to simultaneously achieve wastewater treatment, renewable energy generation and chemicals production. Currently, the CO2 valorization via MES is restricted by the low production rate, while that via electrochemical reduction is limited by the production of C1 products with high efficiency and selectivity. The electrocatalyst-assisted MES could potentially solve these bottlenecks of both MES and electrochemical reduction technology by increasing the production rate and expanding the product range. Here, four types of metals were evaluated for mixed culture-based, electrocatalyst-assisted MES with the fabrication of electrical-biological hybrid cathodes. Cathodes based on In, Zn, Ti and Cu showed high parallelism at 30 A/m2. However, no parallelism was observed at 50 A/m2, and only Zn experienced a further increase of the maximum acetic acid production rate (1.23 ± 0.02 g/L/d, 313 ± 5 g/m2/d) and titer (9.2 ± 0.1 g/L), with the highest value of the production rate normalized to the project area of the fiber cathodes. Other volatile fatty acids and ethanol were below 0.5 g/L. Moreover, it was the sharp H2 generation, which mainly caused the fluctuation of coulombic efficiency. The application of such Zn-based electrical-biological hybrid system shall provide a more efficient route for CO2 valorization.
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Affiliation(s)
- Yong Jiang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Na Chu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Wei Zhang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Junjun Ma
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, PR China
| | - Fang Zhang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Peng Liang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, PR China
| | - Raymond Jianxiong Zeng
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.
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Guzman MS, Rengasamy K, Binkley MM, Jones C, Ranaivoarisoa TO, Singh R, Fike DA, Meacham JM, Bose A. Phototrophic extracellular electron uptake is linked to carbon dioxide fixation in the bacterium Rhodopseudomonas palustris. Nat Commun 2019; 10:1355. [PMID: 30902976 PMCID: PMC6430793 DOI: 10.1038/s41467-019-09377-6] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 03/07/2019] [Indexed: 01/06/2023] Open
Abstract
Extracellular electron uptake (EEU) is the ability of microbes to take up electrons from solid-phase conductive substances such as metal oxides. EEU is performed by prevalent phototrophic bacterial genera, but the electron transfer pathways and the physiological electron sinks are poorly understood. Here we show that electrons enter the photosynthetic electron transport chain during EEU in the phototrophic bacterium Rhodopseudomonas palustris TIE-1. Cathodic electron flow is also correlated with a highly reducing intracellular redox environment. We show that reducing equivalents are used for carbon dioxide (CO2) fixation, which is the primary electron sink. Deletion of the genes encoding ruBisCO (the CO2-fixing enzyme of the Calvin-Benson-Bassham cycle) leads to a 90% reduction in EEU. This work shows that phototrophs can directly use solid-phase conductive substances for electron transfer, energy transduction, and CO2 fixation. Extracellular electron uptake (EEU) is the ability of microbes to take up electrons from solid-phase conductive substances such as metal oxides. Here, Guzman et al. show that electrons enter the photosynthetic electron transport chain and are used for CO2 fixation during EEU in a phototrophic bacterium.
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Affiliation(s)
- Michael S Guzman
- Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Karthikeyan Rengasamy
- Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Michael M Binkley
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Clive Jones
- Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | | | - Rajesh Singh
- Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - David A Fike
- Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - J Mark Meacham
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO, 63130, USA.,Institute of Materials Science Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Arpita Bose
- Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA.
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