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Zhuang X, Wang S, Wu S. Electron Transfer in the Biogeochemical Sulfur Cycle. Life (Basel) 2024; 14:591. [PMID: 38792612 PMCID: PMC11123123 DOI: 10.3390/life14050591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 04/30/2024] [Accepted: 05/02/2024] [Indexed: 05/26/2024] Open
Abstract
Microorganisms are key players in the global biogeochemical sulfur cycle. Among them, some have garnered particular attention due to their electrical activity and ability to perform extracellular electron transfer. A growing body of research has highlighted their extensive phylogenetic and metabolic diversity, revealing their crucial roles in ecological processes. In this review, we delve into the electron transfer process between sulfate-reducing bacteria and anaerobic alkane-oxidizing archaea, which facilitates growth within syntrophic communities. Furthermore, we review the phenomenon of long-distance electron transfer and potential extracellular electron transfer in multicellular filamentous sulfur-oxidizing bacteria. These bacteria, with their vast application prospects and ecological significance, play a pivotal role in various ecological processes. Subsequently, we discuss the important role of the pili/cytochrome for electron transfer and presented cutting-edge approaches for exploring and studying electroactive microorganisms. This review provides a comprehensive overview of electroactive microorganisms participating in the biogeochemical sulfur cycle. By examining their electron transfer mechanisms, and the potential ecological and applied implications, we offer novel insights into microbial sulfur metabolism, thereby advancing applications in the development of sustainable bioelectronics materials and bioremediation technologies.
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Affiliation(s)
- Xuliang Zhuang
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; (X.Z.); (S.W.)
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Shijie Wang
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; (X.Z.); (S.W.)
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shanghua Wu
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; (X.Z.); (S.W.)
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
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2
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Mills S, Trego AC, Prevedello M, De Vrieze J, O’Flaherty V, Lens PN, Collins G. Unifying concepts in methanogenic, aerobic, and anammox sludge granulation. ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY 2024; 17:100310. [PMID: 37705860 PMCID: PMC10495608 DOI: 10.1016/j.ese.2023.100310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 06/17/2023] [Accepted: 08/05/2023] [Indexed: 09/15/2023]
Abstract
The retention of dense and well-functioning microbial biomass is crucial for effective pollutant removal in several biological wastewater treatment technologies. High solids retention is often achieved through aggregation of microbial communities into dense, spherical aggregates known as granules, which were initially discovered in the 1980s. These granules have since been widely applied in upflow anaerobic digesters for waste-to-energy conversions. Furthermore, granular biomass has been applied in aerobic wastewater treatment and anaerobic ammonium oxidation (anammox) technologies. The mechanisms underpinning the formation of methanogenic, aerobic, and anammox granules are the subject of ongoing research. Although each granule type has been extensively studied in isolation, there has been a lack of comparative studies among these granulation processes. It is likely that there are some unifying concepts that are shared by all three sludge types. Identifying these unifying concepts could allow a unified theory of granulation to be formed. Here, we review the granulation mechanisms of methanogenic, aerobic, and anammox granular sludge, highlighting several common concepts, such as the role of extracellular polymeric substances, cations, and operational parameters like upflow velocity and shear force. We have then identified some unique features of each granule type, such as different internal structures, microbial compositions, and quorum sensing systems. Finally, we propose that future research should prioritize aspects of microbial ecology, such as community assembly or interspecies interactions in individual granules during their formation and growth.
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Affiliation(s)
- Simon Mills
- Microbial Communities Laboratory, School of Biological and Chemical Sciences, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
| | - Anna Christine Trego
- Microbial Ecology Laboratory School of Biological and Chemical Sciences, University of Galway, University Road, Galway, H91 TK33, Ireland
| | - Marco Prevedello
- Microbial Communities Laboratory, School of Biological and Chemical Sciences, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
| | - Jo De Vrieze
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, B-9000, Gent, Belgium
| | - Vincent O’Flaherty
- Microbial Ecology Laboratory School of Biological and Chemical Sciences, University of Galway, University Road, Galway, H91 TK33, Ireland
| | - Piet N.L. Lens
- University of Galway, University Road, Galway, H91 TK33, Ireland
| | - Gavin Collins
- Microbial Communities Laboratory, School of Biological and Chemical Sciences, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
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3
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Abstract
A wide diversity of microorganisms, typically growing as biofilms, has been implicated in corrosion, a multi-trillion dollar a year problem. Aerobic microorganisms establish conditions that promote metal corrosion, but most corrosion has been attributed to anaerobes. Microbially produced organic acids, sulfide and extracellular hydrogenases can accelerate metallic iron (Fe0) oxidation coupled to hydrogen (H2) production, as can respiratory anaerobes consuming H2 as an electron donor. Some bacteria and archaea directly accept electrons from Fe0 to support anaerobic respiration, often with c-type cytochromes as the apparent outer-surface electrical contact with the metal. Functional genetic studies are beginning to define corrosion mechanisms more rigorously. Omics studies are revealing which microorganisms are associated with corrosion, but new strategies for recovering corrosive microorganisms in culture are required to evaluate corrosive capabilities and mechanisms. Interdisciplinary studies of the interactions among microorganisms and between microorganisms and metals in corrosive biofilms show promise for developing new technologies to detect and prevent corrosion. In this Review, we explore the role of microorganisms in metal corrosion and discuss potential ways to mitigate it.
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Affiliation(s)
- Dake Xu
- Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang, China
- Shenyang National Laboratory for Materials Science, Northeastern University, Shenyang, China
| | - Tingyue Gu
- Department of Chemical & Biomolecular Engineering, Ohio University, Athens, OH, USA.
- Department of Biological Sciences, Ohio University, Athens, OH, USA.
- Institute for Corrosion and Multiphase Technology, Ohio University, Athens, OH, USA.
- Institute for Sustainable Energy and the Environment, Ohio University, Athens, OH, USA.
| | - Derek R Lovley
- Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang, China
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
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4
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Zhong Y, He J, Duan S, Cai Q, Pan X, Zou X, Zhang P, Zhang J. Revealing the mechanism of novel nitrogen-doped biochar supported magnetite (NBM) enhancing anaerobic digestion of waste-activated sludge by sludge characteristics. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 340:117982. [PMID: 37119625 DOI: 10.1016/j.jenvman.2023.117982] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/17/2023] [Accepted: 04/17/2023] [Indexed: 05/12/2023]
Abstract
Anaerobic digestion (AD) is a promising technology in waste treatment and energy recovery. However, it suffers from long retention time and low biogas yield. In this study, novel nitrogen-doped biochar supported magnetite (NBM) was synthesized and applied to enhance the AD of waste-activated sludge. Results showed that NBM increased cumulative methane production and SCOD removal efficiency by up to 1.75 times and 15% respectively at 5 g/L compared with the blank. NBM enhanced both hydrolysis and methanogenesis process during AD and the activities of α-glucosidase, protease, coenzyme F420 and electron transport system were increased by 19%, 163%, 104% and 160% respectively at 5 g/L NBM compared with the blank. NBM also facilitated the secretion of conductive protein in extracellular polymeric substances as well as the formation of conductive pili, leading to 3.18-7.59 times higher sludge electrical conductivity. Microbial community analysis revealed that bacteria Clostridia and archaea Methanosarcina and Methanosaeta were enriched by the addition of NBM, and direct interspecies electron transfer might be promoted between them. This study provides a practical reference for future material synthesis and its application.
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Affiliation(s)
- Yijie Zhong
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
| | - Junguo He
- School of Civil Engineering, Guangzhou University, Guangzhou, 510006, PR China.
| | - Shengye Duan
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Qiupeng Cai
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Xinlei Pan
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Xiang Zou
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Pengfei Zhang
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Jie Zhang
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, PR China
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5
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Huang X, Miao X, Chu X, Luo L, Zhang H, Sun Y. Enhancement effect of biochar addition on anaerobic co-digestion of pig manure and corn straw under biogas slurry circulation. BIORESOURCE TECHNOLOGY 2023; 372:128654. [PMID: 36682475 DOI: 10.1016/j.biortech.2023.128654] [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: 11/18/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 06/17/2023]
Abstract
Based on the semi-continuous anaerobic co-digestion (AcoD) reactor, the effects of biochar addition on the internal environmental changes and gas production characteristics were studied under the condition of biogas slurry recirculation. The results showed that the addition of biochar enhanced the degradation and metabolic pathways of acetate and propionate, thereby reducing the concentrations of volatile fatty acids (VFAs), total ammonia and chemical oxygen demand by 55 %, 41 % and 61 %, respectively. The buffer system formed by the combination of NH4+ and VFAs of C2-C5 was also enhanced, thereby improving the stability of the system. The addition of biochar effectively increased the relative abundance of Bacteroidetes, Chloroflexi, Spirochaetota and Synergistota, and enhanced three methanogenic metabolic pathways. This study provides scientific support for the application of biochar to solve the system inhibition in mixed substrate semi-continuous AcoD process and provides technical support for the stable operation of biogas project.
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Affiliation(s)
- Xinning Huang
- Northeast Agriculture University, Harbin 15000, China; Key Laboratory of Agricultural Renewable Resources Utilization Technology and Equipment in Cold Areas of Heilongjiang Province, Harbin 150030, China; Key Laboratory of Pig-breeding Facilities Engineering, Ministry of Agriculture, Harbin 15000, China
| | - Xinying Miao
- Northeast Agriculture University, Harbin 15000, China; Key Laboratory of Agricultural Renewable Resources Utilization Technology and Equipment in Cold Areas of Heilongjiang Province, Harbin 150030, China; Key Laboratory of Pig-breeding Facilities Engineering, Ministry of Agriculture, Harbin 15000, China
| | - Xiaodong Chu
- Northeast Agriculture University, Harbin 15000, China; Key Laboratory of Agricultural Renewable Resources Utilization Technology and Equipment in Cold Areas of Heilongjiang Province, Harbin 150030, China; Key Laboratory of Pig-breeding Facilities Engineering, Ministry of Agriculture, Harbin 15000, China
| | - Lina Luo
- Northeast Agriculture University, Harbin 15000, China; Key Laboratory of Agricultural Renewable Resources Utilization Technology and Equipment in Cold Areas of Heilongjiang Province, Harbin 150030, China; Key Laboratory of Pig-breeding Facilities Engineering, Ministry of Agriculture, Harbin 15000, China
| | - Hongqiong Zhang
- Northeast Agriculture University, Harbin 15000, China; Key Laboratory of Agricultural Renewable Resources Utilization Technology and Equipment in Cold Areas of Heilongjiang Province, Harbin 150030, China; Key Laboratory of Pig-breeding Facilities Engineering, Ministry of Agriculture, Harbin 15000, China
| | - Yong Sun
- Northeast Agriculture University, Harbin 15000, China; Key Laboratory of Agricultural Renewable Resources Utilization Technology and Equipment in Cold Areas of Heilongjiang Province, Harbin 150030, China; Key Laboratory of Pig-breeding Facilities Engineering, Ministry of Agriculture, Harbin 15000, China.
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6
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Gu Y, Qi X, Yang X, Jiang Y, Liu P, Quan X, Liang P. Extracellular electron transfer and the conductivity in microbial aggregates during biochemical wastewater treatment: A bottom-up analysis of existing knowledge. WATER RESEARCH 2023; 231:119630. [PMID: 36689883 DOI: 10.1016/j.watres.2023.119630] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 12/14/2022] [Accepted: 01/15/2023] [Indexed: 06/17/2023]
Abstract
Microbial extracellular electron transfer (EET) plays a crucial role in bioenergy production and resource recovery from wastewater. Interdisciplinary efforts have been made to unveil EET processes at various spatial scales, from nanowires to microbial aggregates. Electrical conductivity has been frequently measured as an indicator of EET efficiency. In this review, the conductivity of nanowires, biofilms, and granular sludge was summarized, and factors including subjects, measurement methods, and conducting conditions that affect the conductivity difference were discussed in detail. The high conductivity of nanowires does not necessarily result in efficient EET in microbial aggregates due to the existence of non-conductive substances and contact resistance. Improving the conductivity measurement of microbial aggregates is important because it enables the calculation of an EET flux from conductivity and a comparison of the flux with mass transfer coefficients. This review provides new insight into the significance, characterization, and optimization of EET in microbial aggregates during a wastewater treatment process.
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Affiliation(s)
- Yuyi Gu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Xiang Qi
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Xufei Yang
- Department of Agricultural and Biosystems Engineering, South Dakota State University, Brookings, SD 57007 USA
| | - 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
| | - Panpan Liu
- School of Ecology and Environment, Zhengzhou University, Zhengzhou 450001, PR China
| | - Xiangchun Quan
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Peng Liang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China.
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7
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Wang Y, Gao Y, Hussain A, Lee HS. Optimization of biofilm conductance measurement with two-electrode microbial electrochemical cells (MECs). THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 858:159577. [PMID: 36283518 DOI: 10.1016/j.scitotenv.2022.159577] [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: 08/17/2022] [Revised: 10/14/2022] [Accepted: 10/15/2022] [Indexed: 06/16/2023]
Abstract
This study was conducted to develop a standardized and consistent method for biofilm conductance measurement for an improved comprehension of extracellular electron transfer. Biofilm conductance (2.12 ± 0.25 × 10-4 S) with and without a fixed anode potential did not show significant difference. The conductance showed a sigmoidal relationship with anode potential. The current-voltage profile of the tested biofilm at applied voltage larger than 100 mV showed deviation from Ohm's law. Up to 69% decrease in biofilm conductance and deviation from Ohm's law were observed in the current-voltage profile when the measurement time increased. By choosing the voltage range (0- 100 mV) and step (25 mV), measurement time (100-s at each voltage step), and anode control mode, these operation settings were found more suitable for consistent and accurate biofilm conductance measurement in the 2-Au MEC system. This represents the first study that comprehensively evaluated the environmental and instrumental parameters for biofilm conductance measurement.
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Affiliation(s)
- Yifei Wang
- Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Yaohuan Gao
- School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, PR China
| | - Abid Hussain
- Department of Civil and Environmental Engineering, Carleton University, Ottawa, ON, Canada
| | - Hyung-Sool Lee
- Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada; Institute for Environmental and Climate Technology, Korea Institute of Energy Technology, Naju-si, Jeollanam-do, Republic of Korea.
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8
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Olatunji KO, Madyira DM, Ahmed NA, Ogunkunle O. Experimental evaluation of the influence of combined particle size pretreatment and Fe 3O 4 additive on fuel yields of Arachis Hypogea shells. WASTE MANAGEMENT & RESEARCH : THE JOURNAL OF THE INTERNATIONAL SOLID WASTES AND PUBLIC CLEANSING ASSOCIATION, ISWA 2023; 41:467-476. [PMID: 36128600 PMCID: PMC9925899 DOI: 10.1177/0734242x221122560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 07/03/2022] [Indexed: 06/15/2023]
Abstract
A smart energy recovery process can achieve maximum energy recovery from organic wastes. Pretreatment of feedstock is essential to biogas and methane yields during the anaerobic digestion process. This work combined particle size reduction with Fe3O4 nanoparticles to investigate their influence on biogas and methane yields from anaerobic digestion of Arachis hypogea shells. Twenty milligrams per litre of Fe3O4 nanoparticles was implemented with 2, 4, 6 and 8 mm particle sizes and a single treatment of Fe3O4 for 35 days. The treatments were compared with each other and were discovered to significantly (p < 0.05) enhance biogas yield by 37.40%, 50.10%, 54.40%, 51.40% and 35.50% compared with control, respectively. Specific biogas yield recorded was 966.2, 1406, 1552.7, 1317.4, 766.2 and 413 mL g-1 volatile solid. This study showed the combination of Fe3O4 with 6 mm particle size of Arachis hypogea shells produced the optimum biogas and methane yields. The addition of Fe3O4 to particle sizes below 6 mm resulted in over-accumulation of volatile fatty acids and lowered the gas yield. This can be applied on an industrial scale.
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Affiliation(s)
- Kehinde O Olatunji
- Kehinde O Olatunji, Department of
Mechanical Engineering Science, Faculty of Engineering and the Built
Environment, University of Johannesburg, B3 Lab 22, Johannesburg 200, South
Africa.
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9
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Xu W, He X, Wang C, Zhao Z. Effect of granular activated carbon adsorption and size of microbial aggregates in inoculum on stimulating direct interspecies electron transfer during anaerobic digestion of fat, oil, and grease. BIORESOURCE TECHNOLOGY 2023; 368:128289. [PMID: 36372383 DOI: 10.1016/j.biortech.2022.128289] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 11/01/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
To investigate the effect of granular activated carbon (GAC) adsorption and size of microbial aggregates in inoculum on stimulating direct interspecies electron transfer (DIET) during anaerobic digestion of fat, oil, and grease (FOG), seed sludge was divided into two inocula (big (>0.85 mm)/small (0.15-0.85 mm)) for FOG digestion with/without GAC. More long-chain fatty acids (LCFAs) were adsorbed on GAC in the reactor with small aggregates than that with big aggregates, corresponding to 57 % and 10 % decreased methane production, respectively. Adsorption of unsaturated LCFAs (e.g., oleic acid) on GAC was found to reduce LCFA bioavailability, hinder DIET via GAC, and change community structure. Compared to pre-adsorption of oleic acid on GAC, pre-attachment of microbes on GAC resulted in 5.6-fold higher methane yield for oleic acid digestion. Together, competition of LCFA adsorption between GAC and microbial aggregates is essential for enhanced methane recovery from FOG digestion via GAC-induced DIET.
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Affiliation(s)
- Weijia Xu
- College of Environmental Science and Engineering, Guilin University of Technology, Guangxi 541006, China
| | - Xia He
- College of Environmental Science and Engineering, Guilin University of Technology, Guangxi 541006, China; Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541006, China.
| | - Chun Wang
- College of Environmental Science and Engineering, Guilin University of Technology, Guangxi 541006, China
| | - Zihao Zhao
- College of Environmental Science and Engineering, Guilin University of Technology, Guangxi 541006, China
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10
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Wu F, Xie J, Xin X, He J. Effect of activated carbon/graphite on enhancing anaerobic digestion of waste activated sludge. Front Microbiol 2022; 13:999647. [DOI: 10.3389/fmicb.2022.999647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 08/25/2022] [Indexed: 11/16/2022] Open
Abstract
The conductive media was capable to enhance anaerobic digestion and promote direct interspecific electron transfer (DIET). In this study, the effects of activated carbon- and graphite-conductive media on promoting anaerobic digestion efficiency of waste activated sludge were experimentally studied. The results show that the 100 mesh-activated carbon group reactor produced a largest biogas yield of 468.2 mL/g VSS, which was 13.8% higher than the blank test. The graphite group reactor with 400-grain size produced a largest biogas yield of 462.9 mL/g VSS, which was 12.5% higher than the blank test. Moreover, the optimal particle size of such two carbon- conductive mediators were optimized for enhancing degradation efficiency of VSS, TCOD, total protein and total polysaccharide of waste sludge. Activated carbon was capable to promote the hydrolytic acidification stage in anaerobic digestion of waste sludge. When the particle size reduced to the optimal particle size, the promoting effect could be strengthened for producing more hydrolytic acidification products for methanogenesis. However, in the graphite group, the methane production is increased by promoting the consumption of hydrolysis and acidification products and is enhanced with the particle size reduction, thus promoting the methanogenesis process, and improving the anaerobic digestion efficiency. Microbial community analysis showed that both activated carbon and graphite cultivated the genera of Methanosaeta, Methanobacterium, Nitrososphaeraceae, which promoted the improvement of methane production through the acetate debris methanogenesis pathway.
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11
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Towards engineering application: Integrating current strategies of promoting direct interspecies electron transfer to enhance anaerobic digestion. CHEMICAL ENGINEERING JOURNAL ADVANCES 2022. [DOI: 10.1016/j.ceja.2022.100405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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12
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Sun Y, Wang M, Liang L, Sun C, Wang X, Wang Z, Zhang Y. Continuously feeding fenton sludge into anaerobic digesters: Iron species change and operating stability. WATER RESEARCH 2022; 226:119283. [PMID: 36308793 DOI: 10.1016/j.watres.2022.119283] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
Fenton sludge generated from the Fenton process contains a large number of ferric species and organic pollutants, which need to be properly treated before discharge. In this study, Fenton sludge as an Fe(III) source for dissimilatory iron reduction (DIR) was continuously added with increasing dosage into an anaerobic digester to enhance the treatment. Results showed continuously feeding Fenton sludge to the anaerobic digester did not deteriorate the performance and increased methane production and COD removal rate by 2.2 folds and 14.0%, respectively. The Fe content of sludge in the digester increased from 40.25 mg/g (dry weight) to 131.53 mg/g after continuously feeding for 77days, and then declined to 109.17 mg/g when the feeding was stopped. Mass balance analysis showed that 20.5 to 48.4% of Fe in the Fenton sludge was released to the effluent. After experiment, the ratio of reducible Fe species to the total Fe was 75.1%, which maintained the high activity in DIR. Microbial community analysis showed that iron-reducing bacteria were enriched with the addition of Fenton sludge and the sludge in the digester had a higher conductivity and capacitance to strengthen the electron transfer of DIR. All results suggested that feeding Fenton sludge into anaerobic digesters was a feasible method to dispose of Fenton sludge as well as to enhance the performance of anaerobic digestion.
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Affiliation(s)
- Ye Sun
- Dalian University of Technology School of Environmental Science and Technology, No.2 Linggong Road, Ganjingzi District. Dalian, Liaoning 116024, China
| | - Mingwei Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Lianfu Liang
- Dalian University of Technology School of Environmental Science and Technology, No.2 Linggong Road, Ganjingzi District. Dalian, Liaoning 116024, China
| | - Cheng Sun
- Dalian University of Technology School of Environmental Science and Technology, No.2 Linggong Road, Ganjingzi District. Dalian, Liaoning 116024, China
| | - Xuepeng Wang
- Dalian University of Technology School of Environmental Science and Technology, No.2 Linggong Road, Ganjingzi District. Dalian, Liaoning 116024, China
| | - Zhenxin Wang
- Dalian University of Technology School of Environmental Science and Technology, No.2 Linggong Road, Ganjingzi District. Dalian, Liaoning 116024, China
| | - Yaobin Zhang
- Dalian University of Technology School of Environmental Science and Technology, No.2 Linggong Road, Ganjingzi District. Dalian, Liaoning 116024, China.
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13
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Neu J, Shipps CC, Guberman-Pfeffer MJ, Shen C, Srikanth V, Spies JA, Kirchhofer ND, Yalcin SE, Brudvig GW, Batista VS, Malvankar NS. Microbial biofilms as living photoconductors due to ultrafast electron transfer in cytochrome OmcS nanowires. Nat Commun 2022; 13:5150. [PMID: 36071037 PMCID: PMC9452534 DOI: 10.1038/s41467-022-32659-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 08/09/2022] [Indexed: 11/09/2022] Open
Abstract
Light-induced microbial electron transfer has potential for efficient production of value-added chemicals, biofuels and biodegradable materials owing to diversified metabolic pathways. However, most microbes lack photoactive proteins and require synthetic photosensitizers that suffer from photocorrosion, photodegradation, cytotoxicity, and generation of photoexcited radicals that are harmful to cells, thus severely limiting the catalytic performance. Therefore, there is a pressing need for biocompatible photoconductive materials for efficient electronic interface between microbes and electrodes. Here we show that living biofilms of Geobacter sulfurreducens use nanowires of cytochrome OmcS as intrinsic photoconductors. Photoconductive atomic force microscopy shows up to 100-fold increase in photocurrent in purified individual nanowires. Photocurrents respond rapidly (<100 ms) to the excitation and persist reversibly for hours. Femtosecond transient absorption spectroscopy and quantum dynamics simulations reveal ultrafast (~200 fs) electron transfer between nanowire hemes upon photoexcitation, enhancing carrier density and mobility. Our work reveals a new class of natural photoconductors for whole-cell catalysis. Despite enormous potential of solar-driven biocatalysis, most living systems lack photoactive proteins and require toxic and expensive synthetic materials limiting the performance. Here, a class of natural photoconductors is demonstrated through sub-picosecond heme-to-heme electron transfer in bacteria-produced protein nanowires.
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Affiliation(s)
- Jens Neu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA. .,Microbial Sciences Institute, Yale University, West Haven, CT, USA.
| | - Catharine C Shipps
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Matthew J Guberman-Pfeffer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Cong Shen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Vishok Srikanth
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Jacob A Spies
- Department of Chemistry, Yale University, New Haven, CT, USA
| | | | - Sibel Ebru Yalcin
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Gary W Brudvig
- Department of Chemistry, Yale University, New Haven, CT, USA
| | | | - Nikhil S Malvankar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA. .,Microbial Sciences Institute, Yale University, West Haven, CT, USA.
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14
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Zhu Y, Jin Z, Yu Q, Zhao Z, Zhang Y. Alleviating acid inhibition in anaerobic digestion of food waste: Coupling ethanol-type fermentation with biochar addition. ENVIRONMENTAL RESEARCH 2022; 212:113355. [PMID: 35472467 DOI: 10.1016/j.envres.2022.113355] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 06/14/2023]
Abstract
In this study, ethanol-type fermentation pretreatment and adding two types of biochar prepared at 600 °C and 1000 °C (referred to as SS600 and SS1000) were combined to alleviate acid accumulation via strengthening direct interspecies electron transfer (DIET) during anaerobic digestion of food waste. Results demonstrated that ethanol production was about 11 g/L after the ethanol-type fermentation at pH of 4-5 for 4 days, accounting for 8.9% of the influent COD of the subsequent methanogenesis. After the ethanol-type fermentation pretreatment, average methane productions of digesters with SS600 and SS1000 addition increased by 86.3% and 64.9% to 618.1 ± 30.1 and 527.3 ± 25.4 mL/g VS under solid retention time (SRT) of 25 d respectively, and the conductivity of sludge increased by 95.3% and 65.3% compared to digester without biochar addition. Furthermore, adding biochar also could accelerate the recovery of acidification digester. The relative abundance of Methanothrix performing DIET were enriched with SS600. These results suggested that coupling ethanol-type fermentation with biochar addition could strengthen DIET to resist the shocks of high organic loading rate.
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Affiliation(s)
- Yahui Zhu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Zhen Jin
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Qilin Yu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Zhiqiang Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Yaobin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
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15
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Dyksma S, Gallert C. Effect of magnetite addition on transcriptional profiles of syntrophic Bacteria and Archaea during anaerobic digestion of propionate in wastewater sludge. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:664-678. [PMID: 35615789 DOI: 10.1111/1758-2229.13080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/20/2022] [Accepted: 04/24/2022] [Indexed: 05/23/2023]
Abstract
Anaerobic digestion (AD) is an important technology for the effective conversion of waste and wastewater to methane. Here, syntrophic bacteria transfer molecular hydrogen (H2 ), formate, or directly supply electrons (direct interspecies electron transfer, DIET) to the methanogens. Evidence is accumulating that the methanation of short-chain fatty acids can be enhanced by the addition of conductive material to the anaerobic digester, which has often been attributed to the stimulation of DIET. Since little is known about the transcriptional response of a complex AD microbial community to the addition of conductive material, we added magnetite to propionate-fed laboratory-scale reactors that were inoculated with wastewater sludge. Compared to the control reactors, the magnetite-amended reactors showed improved methanation of propionate. A genome-centric metatranscriptomics approach identified the active SCFA-oxidizing bacteria that affiliated with Firmicutes, Desulfobacterota and Cloacimonadota. The transcriptional profiles revealed that the syntrophic bacteria transferred acetate, H2 and formate to acetoclastic and hydrogenotrophic methanogens, whereas transcription of potential determinants for DIET such as conductive pili and outer-membrane cytochromes did not significantly change with magnetite addition. Overall, changes in the transcriptional profiles of syntrophic Bacteria and Archaea in propionate-fed lab-scale reactors amended with magnetite refute a major role of DIET in the studied system.
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Affiliation(s)
- Stefan Dyksma
- Faculty of Technology, Microbiology - Biotechnology, University of Applied Sciences Emden/Leer, Emden, Germany
| | - Claudia Gallert
- Faculty of Technology, Microbiology - Biotechnology, University of Applied Sciences Emden/Leer, Emden, Germany
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16
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Logan M, Tan LC, Nzeteu CO, Lens PNL. Enhanced anaerobic digestion of dairy wastewater in a granular activated carbon amended sequential batch reactor. GLOBAL CHANGE BIOLOGY. BIOENERGY 2022; 14:840-857. [PMID: 35915605 PMCID: PMC9324911 DOI: 10.1111/gcbb.12947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/21/2022] [Accepted: 03/29/2022] [Indexed: 06/15/2023]
Abstract
This study investigated the potential of granular activated carbon (GAC) supplementation to enhance anaerobic degradation of dairy wastewater. Two sequential batch reactors (SBRs; 0.8 L working volume), one control and another amended with GAC, were operated at 37°C and 1.5-1.6 m/h upflow velocity for a total of 120 days (four cycles of 30 days each). The methane production at the end of each cycle run increased by about 68%, 503%, 110%, and 125% in the GAC-amended SBR, compared with the Control SBR. Lipid degradation was faster in the presence of GAC. Conversely, the organic compounds, especially lipids, accumulated in the absence of the conductive material. In addition, a reduction in lag phase duration by 46%-100% was observed at all four cycles in the GAC-amended SBR. The peak methane yield rate was at least 2 folds higher with GAC addition in all cycles. RNA-based bacterial analysis revealed enrichment of Synergistes (0.8% to 29.2%) and Geobacter (0.4% to 11.3%) in the GAC-amended SBR. Methanolinea (85.8%) was the dominant archaea in the biofilm grown on GAC, followed by Methanosaeta (11.3%), at RNA level. Overall, this study revealed that GAC supplementation in anaerobic digesters treating dairy wastewater can promote stable and efficient methane production, accelerate lipid degradation and might promote the activity of electroactive microorganisms.
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Affiliation(s)
| | - Lea Chua Tan
- National University of Ireland, GalwayGalwayIreland
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17
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Li Y, Liang L, Sun C, Wang Z, Yu Q, Zhao Z, Zhang Y. Glycol/glycerol-fed electrically conductive aggregates suggest a mechanism of stimulating direct interspecies electron transfer in methanogenic digesters. WATER RESEARCH 2022; 217:118448. [PMID: 35430471 DOI: 10.1016/j.watres.2022.118448] [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: 01/16/2022] [Revised: 04/05/2022] [Accepted: 04/08/2022] [Indexed: 06/14/2023]
Abstract
The possibility of stimulating direct interspecies electron transfer (DIET) within aggregates of methanogenic digesters respectively with ethanol, glycol, and glycerol as a primary substrate was investigated to better understand the mechanisms of alcohol compounds stimulating DIET. Aggregates fed with ethanol, glycol, and glycerol were electrically conductive (10.4-19.4 uS/cm), with a temperature dependence of metallic-like conductivity. Close examination of transmission electron microscope images observed the potential interspecies connected networks assembled by filaments within these aggregates. Further investigations via metatranscriptomics found that, genes for electrically conductive pili (e-pili) (Log2FPKM, 9.39-10.96) and c-type cytochromes (8.90-9.64) were highly expressed within aggregates. Glycerol-fed aggregates exhibited the highest gene expression for e-pili, while glycol-fed aggregates exhibited the highest gene expression for c-type cytochromes. Methanothrix species were dominant and metabolically active within aggregates. Genes encoding the enzymes involved in carbon dioxide reduction were highly expressed in Methanothrix species, suggesting that they participated in DIET. In addition, transcript abundance of genes encoding alcohol dehydrogenase and NADH-quinone oxidoreductase in alcohol dehydrogenation closely associated with NADH/NAD+ transformation within glycol- and glycerol-fed aggregates was generally higher than that within ethanol-fed aggregates. These results, and the fact that NADH/NAD+ transformation was very linked to the ATP synthesis complex that further supported the formation of extracellular electrical connection components, e-pili and membrane-bound multi-heme c-type cytochromes (MHCs), provided a possibility that alcohol compounds comprised of hydroxy groups could stimulate DIET and more hydroxy groups comprised were better for this stimulation.
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Affiliation(s)
- Yuan Li
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Lianfu Liang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Cheng Sun
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Zhenxin Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Qilin Yu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Zhiqiang Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
| | - Yaobin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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18
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Paquete CM, Rosenbaum MA, Bañeras L, Rotaru AE, Puig S. Let's chat: Communication between electroactive microorganisms. BIORESOURCE TECHNOLOGY 2022; 347:126705. [PMID: 35065228 DOI: 10.1016/j.biortech.2022.126705] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 01/07/2022] [Accepted: 01/08/2022] [Indexed: 06/14/2023]
Abstract
Electroactive microorganisms can exchange electrons with other cells or conductive interfaces in their extracellular environment. This property opens the way to a broad range of practical biotechnological applications, from manufacturing sustainable chemicals via electrosynthesis, to bioenergy, bioelectronics or improved, low-energy demanding wastewater treatments. Besides, electroactive microorganisms play key roles in environmental bioremediation, significantly impacting process efficiencies. This review highlights our present knowledge on microbial interactions promoting the communication between electroactive microorganisms in a biofilm on an electrode in bioelectrochemical systems (BES). Furthermore, the immediate knowledge gaps that must be closed to develop novel technologies will also be acknowledged.
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Affiliation(s)
- Catarina M Paquete
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-156 Oeiras, Portugal
| | - Miriam A Rosenbaum
- Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute, Beutenbergstrasse 11a, Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| | - Lluís Bañeras
- Group of Molecular Microbial Ecology, Institute of Aquatic Ecology, University of Girona, C/ Maria Aurèlia Capmany, 40, E-17003 Girona, Spain
| | - Amelia-Elena Rotaru
- Faculty of Natural Sciences, Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Sebastià Puig
- LEQUiA, Institute of the Environment, University of Girona, Carrer Maria Aurelia Capmany, 69, E-17003 Girona, Spain.
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19
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Sun M, Jiang H, Zhang Z, Lv M, Liu G, Feng Y. Coupling direct voltage and granular activated carbon modified nanoscale zero valent iron for enhancing anaerobic methane production. CHEMOSPHERE 2022; 286:131840. [PMID: 34399267 DOI: 10.1016/j.chemosphere.2021.131840] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 07/22/2021] [Accepted: 08/06/2021] [Indexed: 06/13/2023]
Abstract
Anaerobic digestion technology has been widely used because it has a unique advantage of producing biogas as a renewable energy source. Therefore, several methods were studied to facilitate anaerobic methane production process. Coupling direct voltage and single conductive particles was an effective method to improve anaerobic wastewater treatment efficiency and methane production. However, the enhancement method was limited in this process due to the current of direct voltage or the toxicity of nanoparticles. Therefore, the granular activated carbon loaded with nanoscale zero valent iron (GAC-NZVI) particles prepared by co-precipitation method were added to the anaerobic synthetic wastewater system with direct voltage (0.10 V) to improve the treatment efficiency in this study. GAC-NZVI particles were added into anaerobic system with 0.10 V direct voltage to enhance CH4 production process. The COD removal and total CH4 production were enhanced by 4.22 % and 10.83 % with GAC-NZVI particles. The measurement results of EPS and Fe concentration showed that GAC-NZVI particles promoted the secretion of EPS by microorganisms, which could improve the floc strength of granular sludge. The measurements of conductivity and cyclic voltammetry (CV) showed that particles accelerated the metabolism of microorganism and promoted the electron transfer process. The increasing of Methanothrix and Methanobacterium could strengthen the methanogenesis. The abundances of bacteria and archaea using indirect interspecies electron exchange form (such as H2 or formate transfer microorganisms) were decreased after adding the particles. The results indicated that anaerobic treatment efficiency could be enhanced under the combined action of direct voltage and particles.
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Affiliation(s)
- Muchen Sun
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin, 150090, China
| | - Hongxuan Jiang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin, 150090, China
| | - Zhaohan Zhang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin, 150090, China.
| | - Miao Lv
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin, 150090, China
| | - Guohong Liu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin, 150090, China
| | - Yujie Feng
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin, 150090, China.
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20
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Two-Stage Anaerobic Codigestion of Crude Glycerol and Micro-Algal Biomass for Biohydrogen and Methane Production by Anaerobic Sludge Consortium. FERMENTATION-BASEL 2021. [DOI: 10.3390/fermentation7030175] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Optimization of factors affecting biohydrogen production from the codigestion of crude glycerol and microalgal biomass by anaerobic sludge consortium was conducted. The experiments were designed by a response surface methodology with central composite design. The factors affecting the production of hydrogen were the concentrations of crude glycerol, microalgal biomass, and inoculum. The maximum hydrogen production (655.1 mL-H2/L) was achieved with 13.83 g/L crude glycerol, 23.1 g-VS/L microalgal biomass, and 10.3% (v/v) inoculum. The hydrogenic effluents obtained under low, high, and optimal conditions were further used as substrates for methane production. Methane production rates and methane yield of 868.7 mL-CH4/L and 2.95 mL-CH4/L-h were attained with the effluent produced under optimum conditions. The use of crude glycerol and microalgal biomass as cosubstrates had an antagonistic effect on biohydrogen production and a synergistic effect on methane fermentation. The two-stage process provided a more attractive solution, with a total energy of 1.27 kJ/g-VSadded, than the one-stage process.
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21
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Feng D, Guo X, Lin R, Xia A, Huang Y, Liao Q, Zhu X, Zhu X, Murphy JD. How can ethanol enhance direct interspecies electron transfer in anaerobic digestion? Biotechnol Adv 2021; 52:107812. [PMID: 34364985 DOI: 10.1016/j.biotechadv.2021.107812] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 01/25/2023]
Abstract
Anaerobic digestion (AD) of organic waste to produce biogas is a mature biotechnology commercialised for decades. However, the relatively recent discovery of direct interspecies electron transfer (DIET) brings a new opportunity to improve the efficiency of biogas technology. DIET may replace mediated interspecies electron transfer (MIET) by efficient electron transfer between exoelectrogens and electrotrophic methanogens, thereby enhancing yields and rates of biogas production. Ethanol, as the initial electron donor in the discovery of the DIET pathway, is now a "hot topic" in the literature. Recent studies have indicated that ethanol in AD functions not only as the substrate, but also as the precursor to stimulate DIET by enriching exoelectrogens and electrotrophic methanogens for co-digesting complex organic wastes. This review aims to highlight the state of the art and recent advances in ethanol-based DIET in AD. The DIET associated reactions of ethanol oxidation and carbon dioxide reduction are assessed by thermodynamic analysis to reveal the extent of the potential for improvement of the AD processes that utilizes DIET pathways. Three ethanol-based DIET strategies are discussed: (1) ethanol as the sole substrate supplemented with conductive materials in AD, (2) ethanol co-digestion with complex substrates and (3) ethanol-type fermentation prior to AD. This review aims to chart the pathways for improved AD performance by utilizing ethanol-based DIET in specific treatments of biological wastes.
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Affiliation(s)
- Dong Feng
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400044, China; Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China
| | - Xiaobo Guo
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400044, China; Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China
| | - Richen Lin
- MaREI Centre, Environmental Research Institute, University College Cork, Cork, Ireland; Civil, Structural, and Environmental Engineering, School of Engineering and Architecture, University College Cork, Cork, Ireland
| | - Ao Xia
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400044, China; Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China.
| | - Yun Huang
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400044, China; Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China
| | - Qiang Liao
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400044, China; Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China
| | - Xianqing Zhu
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400044, China; Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China
| | - Xun Zhu
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing 400044, China; Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China
| | - Jerry D Murphy
- MaREI Centre, Environmental Research Institute, University College Cork, Cork, Ireland; Civil, Structural, and Environmental Engineering, School of Engineering and Architecture, University College Cork, Cork, Ireland
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22
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Liu X, Zhan J, Liu L, Gan F, Ye J, Nealson KH, Rensing C, Zhou S. In Situ Spectroelectrochemical Characterization Reveals Cytochrome-Mediated Electric Syntrophy in Geobacter Coculture. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:10142-10151. [PMID: 34196176 DOI: 10.1021/acs.est.1c00356] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Direct interspecies electron transfer (DIET) between microbial species prevails in some key microbial consortia. However, the electron transfer mechanism(s) in these consortia is controversial due to lack of efficient characterization methods. Here, we provide an in situ anaerobic spectroelectrochemical coculture cell (in situ ASCC) to induce the formation of DIET coculture biofilm on the interdigitated microelectrode arrays and characterize the electron transfer directly. Two typical Geobacter DIET cocultures, Geobacter metallireducens and wild-type Geobacter sulfurreducens (G.m&G.s) and G. metallireducens and a G. sulfurreducens strain deficient in citrate synthase (G.m&G.s-ΔgltA), were selected. In situ Raman and electrochemical Fourier transform infrared (FTIR) spectroscopy indicated that cytochromes are abundant in the electric syntrophic coculture. Cyclic voltammetry and potential step experiment revealed a diffusion-controlled electron transfer process and the electrochemical gating measurements further demonstrated a cytochrome-mediated electron transfer in the DIET coculture. Furthermore, the G.m&G.s-ΔgltA coculture displayed a higher redox conductivity than the G.m&G.s coculture, consistent with the existence of an intimate and efficient electrical connection between these two species. Our findings provide the first report of a redox-gradient-driven electron transport facilitated by c-type cytochromes in DIET coculture, supporting the model that DIET is mediated by cytochromes and suggest a platform to explore the other DIET consortia.
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Affiliation(s)
- Xing Liu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ji Zhan
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lu Liu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Feiting Gan
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jie Ye
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Kenneth H Nealson
- Department of Earth Science, University of Southern California, Los Angeles, California 90007, United States
| | - Christopher Rensing
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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23
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Li Y, Ma C, Ma J, Guo W, Liu Y, Jing Z, Wang Z, Feng L, Zhang W, Xu Q. Promoting potential direct interspecies electron transfer (DIET) and methanogenesis with nitrogen and zinc doped carbon quantum dots. JOURNAL OF HAZARDOUS MATERIALS 2021; 410:124886. [PMID: 33461102 DOI: 10.1016/j.jhazmat.2020.124886] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 12/14/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
Although it has been demonstrated that one-dimensional, two-dimensional, and three-dimensional carbon nanomaterials can improve the CH4 production of anaerobic digestion (AD), the effect of zero-dimensional carbon nanomaterials on AD have not been reported. To expand the application of carbon nanomaterials in AD, the effect of zero-dimensional carbon nanomaterials-carbon quantum dots (CDs) on various feedstocks (c.a. cellulose, glucose, ethanol, and vinegar residue) were investigated in this study. Results have shown that CH4 yield from ethanol was increased by 24.59% (p = 0.396) after adding 5 g/L zinc doped carbon quantum dots (Zn-doped CDs) while that from vinegar residue was dramatically increased by 230% (p = 0.000) using 5 g/L nitrogen doped carbon quantum dots (N-doped CDs). In addition, photoluminescence demonstrated that CDs acted as a capacitor for transmitting and receiving electrons. Furthermore, co-occurrence network analysis revealed that Clostridiales might be used as a signal source to communicate with other species. This study firstly shifted the application of CDs from fluorescence to AD and manifested its positive impact on AD. In short, these findings provided a better understanding on the effects of CDs on different feedstocks of methanogenesis and revealed new evidence of stimulating methanogenesis via CDs.
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Affiliation(s)
- Yeqing Li
- State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Biogas Upgrading Utilization, College of New Energy and Materials, China University of Petroleum Beijing (CUPB), Beijing 102249, China.
| | - Chengjie Ma
- State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Biogas Upgrading Utilization, College of New Energy and Materials, China University of Petroleum Beijing (CUPB), Beijing 102249, China
| | - Junfei Ma
- State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Biogas Upgrading Utilization, College of New Energy and Materials, China University of Petroleum Beijing (CUPB), Beijing 102249, China
| | - Wenyang Guo
- Henan Academy of Sciences Institute of Biology Co., Ltd, No. 28, Huayuan Road, Jinshui District, Zhengzhou City, Henan Province, China
| | - Ya Liu
- State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Biogas Upgrading Utilization, College of New Energy and Materials, China University of Petroleum Beijing (CUPB), Beijing 102249, China
| | - Zhangmu Jing
- State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Biogas Upgrading Utilization, College of New Energy and Materials, China University of Petroleum Beijing (CUPB), Beijing 102249, China
| | - Zhenxin Wang
- State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Biogas Upgrading Utilization, College of New Energy and Materials, China University of Petroleum Beijing (CUPB), Beijing 102249, China
| | - Lu Feng
- Department of Engineering, Aarhus University, Blichers Allé 20, 8830 Tjele, Denmark
| | - Wuyu Zhang
- Department of Chemistry, University of Louisville, Louisville, KY 40217, United States
| | - Quan Xu
- State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Biogas Upgrading Utilization, College of New Energy and Materials, China University of Petroleum Beijing (CUPB), Beijing 102249, China.
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Controls on Interspecies Electron Transport and Size Limitation of Anaerobically Methane-Oxidizing Microbial Consortia. mBio 2021; 12:mBio.03620-20. [PMID: 33975943 PMCID: PMC8263020 DOI: 10.1128/mbio.03620-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
About 382 Tg yr−1 of methane rising through the seafloor is oxidized anaerobically (W. S. Reeburgh, Chem Rev 107:486–513, 2007, https://doi.org/10.1021/cr050362v), preventing it from reaching the atmosphere, where it acts as a strong greenhouse gas. Microbial consortia composed of anaerobic methanotrophic archaea and sulfate-reducing bacteria couple the oxidation of methane to the reduction of sulfate under anaerobic conditions via a syntrophic process. Recent experimental studies and modeling efforts indicate that direct interspecies electron transfer (DIET) is involved in this syntrophy. Here, we explore a fluorescent in situ hybridization-nanoscale secondary ion mass spectrometry data set of large, segregated anaerobic oxidation of methane (AOM) consortia that reveal a decline in metabolic activity away from the archaeal-bacterial interface and use a process-based model to identify the physiological controls on rates of AOM. Simulations reproducing the observational data reveal that ohmic resistance and activation loss are the two main factors causing the declining metabolic activity, where activation loss dominated at a distance of <8 μm. These voltage losses limit the maximum spatial distance between syntrophic partners with model simulations, indicating that sulfate-reducing bacterial cells can remain metabolically active up to ∼30 μm away from the archaeal-bacterial interface. Model simulations further predict that a hybrid metabolism that combines DIET with a small contribution of diffusive exchange of electron donors can offer energetic advantages for syntrophic consortia.
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25
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Torres K, Álvarez-Hornos FJ, Gabaldón C, Marzal P. Start-Up of Chitosan-Assisted Anaerobic Sludge Bed Reactors Treating Light Oxygenated Solvents under Intermittent Operation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18094986. [PMID: 34067161 PMCID: PMC8125441 DOI: 10.3390/ijerph18094986] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/04/2021] [Accepted: 05/05/2021] [Indexed: 01/20/2023]
Abstract
Quality of the granular sludge developed during the start-up of anaerobic up-flow sludge bed reactors is of crucial importance to ensure the process feasibility of treating industrial wastewater such as those containing solvents. In this study, the microbial granule formation from suspended-growth biomass was investigated in two chitosan-assisted reactors. These reactors operated mimicking industrial sites working with night closures treating a mixture of ethanol, ethyl acetate, and 1-ethoxy-2-propanol. Each reactor operated under different hydrodynamic regimes typical from UASB (R1: <0.15 m h−1) and EGSB (R2: 3 m h−1). High soluble COD removal efficiencies (>90%) accompanied by rapid formation of robust anaerobic granules were achieved at both up-flow velocity levels. After three weeks from the start-up, mean size diameters of 475 µm and 354 µm were achieved for R1 and R2, respectively. The performance of the process was found to be stable for the whole operational period of 106 days treating intermittent OLR up to 13 kg COD m−3 d−1. A memory dose of chitosan at day 42 was beneficial to guarantee good quality of the granules by offsetting the negative impact of intermittent water supply on the granular size. Methanocorpusculum was identified as the dominant archaea at both up-flow velocities. Acetobacterium, Geobacter and Desulfovibrio bacteria were also abundant, demonstrating its role on the degradation of light-oxygenated solvents.
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26
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Zhao Z, Li Y, Zhang Y, Lovley DR. Sparking Anaerobic Digestion: Promoting Direct Interspecies Electron Transfer to Enhance Methane Production. iScience 2020; 23:101794. [PMID: 33294801 PMCID: PMC7695907 DOI: 10.1016/j.isci.2020.101794] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Anaerobic digestion was one of the first bioenergy strategies developed, yet the interactions of the microbial community that is responsible for the production of methane are still poorly understood. For example, it has only recently been recognized that the bacteria that oxidize organic waste components can forge electrical connections with methane-producing microbes through biologically produced, protein-based, conductive circuits. This direct interspecies electron transfer (DIET) is faster than interspecies electron exchange via diffusive electron carriers, such as H2. DIET is also more resilient to perturbations such as increases in organic load inputs or toxic compounds. However, with current digester practices DIET rarely predominates. Improvements in anaerobic digestion associated with the addition of electrically conductive materials have been attributed to increased DIET, but experimental verification has been lacking. This deficiency may soon be overcome with improved understanding of the diversity of microbes capable of DIET, which is leading to molecular tools for determining the extent of DIET. Here we review the microbiology of DIET, suggest molecular strategies for monitoring DIET in anaerobic digesters, and propose approaches for re-engineering digester design and practices to encourage DIET.
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Affiliation(s)
- Zhiqiang Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003-9298, USA
| | - Yang Li
- School of Ocean Science and Technology, Dalian University of Technology, Panjin 124221, China
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003-9298, USA
| | - Yaobin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Derek R. Lovley
- Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110819, China
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003-9298, USA
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27
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Rapid Two Stage Anaerobic Digestion of Nejayote through Microaeration and Direct Interspecies Electron Transfer. Processes (Basel) 2020. [DOI: 10.3390/pr8121614] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Corn is one of the main food products in Mexico. The elaboration of corn-derived products generates wastewater with a high organic load (nejayote). Anaerobic digestion is an indicated treatment for wastewater with high organic loads. The results of this study show that the application of microaeration in the hydrolysis-fermentative reactor increased the percentage of volatile fatty acids (VFA) available in the medium by 62%. The addition of a conductive material, such as granulated activated carbon (GAC), promotes DIET (Direct interspecies electrons transfer) in the methanogenic UASB reactor increasing the methane yield by 55%. Likewise, a great diversity of exoelectrogenic bacteria, with the ability to donate electrons DIET mechanisms, were developed in the GAC biofilm, though interestingly, Peptoclostridium and Clostridium (17.3% and 12.75%, respectively) were detected with a great abundance in the GAC biofilm. Peptoclostridium has not been previously reported as a participant in DIET process.
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28
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Hao J, de Los Reyes Iii FL, He X. Fat, oil, and grease (FOG) deposits yield higher methane than FOG in anaerobic co-digestion with waste activated sludge. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 268:110708. [PMID: 32510442 DOI: 10.1016/j.jenvman.2020.110708] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 04/21/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
The formation of fat, oil, and grease (FOG) deposits in sewers is a global challenge for the maintenance of sewer collection systems. Tons of FOG deposits (FDs) are removed from sewer systems every year and present an opportunity for increased methane production via anaerobic co-digestion with waste activated sludge (WAS) at water resource recovery facilities with existing anaerobic digesters. We hypothesized that FDs have higher biomethane potential than that of FOG (e.g., FOG collected in grease interceptors), because of the reduction of inhibition of long chain fatty acids due to saponification. In this study, substantially enhanced methane production was found in anaerobic co-digestion of WAS with FDs within the substrate to inoculum (S/I) ratio range of 0.25-1.2, and the maximum ultimate methane production (685.7 ± 24.1 mL/gVSadded, at S/I = 0.5) was 4.0 times higher than in the control (with WAS only) after 42 days of incubation. Although the lag phase period was longer in FD co-digestion (S/I = 0.5) than in FOG co-digestion (S/I = 0.5) under the same organic loading (gVS) and two times the COD loading, the daily methane production rate became higher after Day 15 in FD co-digestion. Significantly higher cumulative methane production (10.2%, p < 0.05) was obtained in FD co-digestion than in FOG co-digestion after 42-days. Microbial community analysis revealed higher levels of Geobacter in FD co-digestion, possibly suggesting a role for direct interspecies electron transfer (DIET) between Methanosaeta and Geobacter. This work provides fundamental insights supporting anaerobic co-digestion of FDs with WAS, demonstrating the advantages of FDs compared to FOG as co-substrate for enhanced biomethane recovery.
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Affiliation(s)
- Jiahou Hao
- College of Environmental Science and Engineering, Guilin University of Technology, Guangxi, 541006, China
| | - Francis L de Los Reyes Iii
- Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Xia He
- College of Environmental Science and Engineering, Guilin University of Technology, Guangxi, 541006, China.
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29
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Caizán-Juanarena L, ter Heijne A, Weijma J, Yntema D, Suárez-Zuluaga DA, Buisman CJ. Screening for electrical conductivity in anaerobic granular sludge from full-scale wastewater treatment reactors. Biochem Eng J 2020. [DOI: 10.1016/j.bej.2020.107575] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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30
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Yin Q, Gu M, Hermanowicz SW, Hu H, Wu G. Potential interactions between syntrophic bacteria and methanogens via type IV pili and quorum-sensing systems. ENVIRONMENT INTERNATIONAL 2020; 138:105650. [PMID: 32182450 DOI: 10.1016/j.envint.2020.105650] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/04/2020] [Accepted: 03/09/2020] [Indexed: 06/10/2023]
Abstract
Interspecies electron transfer plays an important role in syntrophic methanogenesis. Direct interspecies electron transfer (DIET) between syntrophic oxidizers and methanogens via conductive pili has been only confirmed in some specific co-cultures. This study examined potential syntrophic cooperation via type IV pili and quorum sensing between widespread syntrophic bacteria and methanogens through a metagenomic analysis of 12 anaerobic sludge samples. We found that Methanosaeta and Methanosarcina, which are reported to have DIET ability, were dominant in most methanogenic samples. Putative conductive pili genes were found in some typical syntrophic bacteria, which has rarely been reported previously. The existence of diverse quorum-sensing genes suggested that various quorum-sensing systems might participate in the communication of anaerobic microorganisms. Specifically, the diffusible signal factor and 3'-5' cyclic diguanosine monophosphate related genes were mainly assigned to syntrophic bacteria. These results suggest that the combined regulation of these signals might be responsible for the biosynthesis of type IV pili and affect syntrophic interaction during methanogenesis. These novel results provide fresh evidence to support the widespread existence of DIET in anaerobic methanogenic systems; therefore, regulating the quorum-sensing system may promote syntrophic interaction.
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Affiliation(s)
- Qidong Yin
- Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, Guangdong, China
| | - Mengqi Gu
- Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, Guangdong, China
| | - Slawomir W Hermanowicz
- Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, Guangdong, China; Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720, USA
| | - Hongying Hu
- Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, Guangdong, China
| | - Guangxue Wu
- Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, Guangdong, China.
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31
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Yee MO, Deutzmann J, Spormann A, Rotaru AE. Cultivating electroactive microbes-from field to bench. NANOTECHNOLOGY 2020; 31:174003. [PMID: 31931483 DOI: 10.1088/1361-6528/ab6ab5] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electromicrobiology is an emerging field investigating and exploiting the interaction of microorganisms with insoluble electron donors or acceptors. Some of the most recently categorized electroactive microorganisms became of interest to sustainable bioengineering practices. However, laboratories worldwide typically maintain electroactive microorganisms on soluble substrates, which often leads to a decrease or loss of the ability to effectively exchange electrons with solid electrode surfaces. In order to develop future sustainable technologies, we cannot rely solely on existing lab-isolates. Therefore, we must develop isolation strategies for environmental strains with electroactive properties superior to strains in culture collections. In this article, we provide an overview of the studies that isolated or enriched electroactive microorganisms from the environment using an anode as the sole electron acceptor (electricity-generating microorganisms) or a cathode as the sole electron donor (electricity-consuming microorganisms). Next, we recommend a selective strategy for the isolation of electroactive microorganisms. Furthermore, we provide a practical guide for setting up electrochemical reactors and highlight crucial electrochemical techniques to determine electroactivity and the mode of electron transfer in novel organisms.
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Affiliation(s)
- Mon Oo Yee
- Nordcee, Department of Biology, University of Southern Denmark, Odense, DK-5230, Denmark
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32
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Walker DJF, Nevin KP, Holmes DE, Rotaru AE, Ward JE, Woodard TL, Zhu J, Ueki T, Nonnenmann SS, McInerney MJ, Lovley DR. Syntrophus conductive pili demonstrate that common hydrogen-donating syntrophs can have a direct electron transfer option. ISME JOURNAL 2020; 14:837-846. [PMID: 31896792 DOI: 10.1038/s41396-019-0575-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/02/2019] [Accepted: 12/16/2019] [Indexed: 11/09/2022]
Abstract
Syntrophic interspecies electron exchange is essential for the stable functioning of diverse anaerobic microbial communities. Hydrogen/formate interspecies electron transfer (HFIT), in which H2 and/or formate function as diffusible electron carriers, has been considered to be the primary mechanism for electron transfer because most common syntrophs were thought to lack biochemical components, such as electrically conductive pili (e-pili), necessary for direct interspecies electron transfer (DIET). Here we report that Syntrophus aciditrophicus, one of the most intensively studied microbial models for HFIT, produces e-pili and can grow via DIET. Heterologous expression of the putative S. aciditrophicus type IV pilin gene in Geobacter sulfurreducens yielded conductive pili of the same diameter (4 nm) and conductance of the native S. aciditrophicus pili and enabled long-range electron transport in G. sulfurreducens. S. aciditrophicus lacked abundant c-type cytochromes often associated with DIET. Pilin genes likely to yield e-pili were found in other genera of hydrogen/formate-producing syntrophs. The finding that DIET is a likely option for diverse syntrophs that are abundant in many anaerobic environments necessitates a reexamination of the paradigm that HFIT is the predominant mechanism for syntrophic electron exchange within anaerobic microbial communities of biogeochemical and practical significance.
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Affiliation(s)
- David J F Walker
- Department of Microbiology, University of Massachusetts-Amherst, Amherst, MA, USA.,Institute for Applied Life Sciences, University of Massachusetts-Amherst, Amherst, MA, USA
| | - Kelly P Nevin
- Department of Microbiology, University of Massachusetts-Amherst, Amherst, MA, USA
| | - Dawn E Holmes
- Department of Microbiology, University of Massachusetts-Amherst, Amherst, MA, USA.,Department of Physical and Biological Science, Western New England University, Springfield, MA, USA
| | - Amelia-Elena Rotaru
- Department of Microbiology, University of Massachusetts-Amherst, Amherst, MA, USA.,Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Joy E Ward
- Department of Microbiology, University of Massachusetts-Amherst, Amherst, MA, USA
| | - Trevor L Woodard
- Department of Microbiology, University of Massachusetts-Amherst, Amherst, MA, USA
| | - Jiaxin Zhu
- Department of Mechanical and Industrial Engineering, University of Massachusetts-Amherst, Amherst, MA, USA
| | - Toshiyuki Ueki
- Department of Microbiology, University of Massachusetts-Amherst, Amherst, MA, USA
| | - Stephen S Nonnenmann
- Institute for Applied Life Sciences, University of Massachusetts-Amherst, Amherst, MA, USA.,Department of Mechanical and Industrial Engineering, University of Massachusetts-Amherst, Amherst, MA, USA
| | - Michael J McInerney
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Derek R Lovley
- Department of Microbiology, University of Massachusetts-Amherst, Amherst, MA, USA. .,Institute for Applied Life Sciences, University of Massachusetts-Amherst, Amherst, MA, USA.
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33
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Liu X, Ye Y, Xiao K, Rensing C, Zhou S. Molecular evidence for the adaptive evolution of Geobacter sulfurreducens to perform dissimilatory iron reduction in natural environments. Mol Microbiol 2019; 113:783-793. [PMID: 31872462 DOI: 10.1111/mmi.14443] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 12/17/2019] [Accepted: 12/19/2019] [Indexed: 02/05/2023]
Abstract
The electrically conductive pili (e-pili) of Geobacter species enable extracellular electron transfer to insoluble metallic minerals, electrodes and other microbial species, which confers biogeochemical significance and global prevalence on Geobacter in diverse anaerobic environments. E-pili are constructed by truncated PilA which is considered to have evolved from full-length pilin by gene fission under positive evolutionary selection. However, this hypothesis is based on phylogenetic analysis and has not yet been experimentally confirmed. Here, we reconstructed an ancestral strain of G. sulfurreducens (designated COMB) carrying full-length PilA by combining genes GSU1496 and GSU1497. The results demonstrated that strain COMB expressed and assembled the full-length fused PilA and exhibited an outer membrane c-type cytochrome profile similar to the wild-type strain. Surprisingly, the generated COMB-pili were also conductive, indicating the evolution of truncated PilA did not occur for conductivity. Moreover, strain COMB minimally reduced Fe(III) oxides but maintained its ability to respire electrodes, demonstrating the truncation of pilin enables iron respiration. This study provides the first experimental evidence that the truncation of pilin in Geobacter species confers adaption to Fe(III)-mineral-mediated selective pressures, and suggests an evolutionary event during which the separation of the GSU1497 gene helped Geobacter survive and thrive in natural environments.
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Affiliation(s)
- Xing Liu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yin Ye
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ke Xiao
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing, China
| | - Christopher Rensing
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
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34
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Xu H, Chang J, Wang H, Liu Y, Zhang X, Liang P, Huang X. Enhancing direct interspecies electron transfer in syntrophic-methanogenic associations with (semi)conductive iron oxides: Effects and mechanisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 695:133876. [PMID: 31756846 DOI: 10.1016/j.scitotenv.2019.133876] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 08/09/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Anaerobic digestion is an effective biological treatment process that produces methane by degrading organic compounds in waste/wastewater. It is a complicated microbial process by metabolic interactions among different types of microorganisms. In this process, efficient interspecies electron transfer between secondary fermenting bacteria and methanogens is the critical process for fast and effective methanogenesis. In syntrophic metabolism, hydrogen or formate has been considered as the conventional electron carrier transferring electrons from secondary fermenting bacteria to hydrogenotrophic methanogens. Recently, direct interspecies electron transfer (DIET) without the involvement of dissolved redox mediators is arousing great concerns and has been regarded as a more efficient and thermodynamically favorable interspecies electron transfer pathway for methanogenesis. Interspecies electron exchange through DIET is accomplished via the membrane-bound cytochromes or conductive pili. Several kinds of exogenously-added conductive or semiconductive iron oxides have been discovered to greatly enhance anaerobic methanogenesis through promoting DIET. Different (semi)conductive iron oxides give a boost to DIET through different mechanisms based on the physicochemical properties of the iron oxides and the reciprocal interactions between iron oxides and functional microorganisms. In this review, the current understanding of interspecies electron transfer in syntrophic-methanogenic consortions is summarized, the effects and deep-rooted mechanisms of (semi)conductive iron oxides on methanogenesis and DIET are discussed, and possible future perspectives and development directions are suggested for DIET via (semi)conductive iron oxides in anaerobic digestion.
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Affiliation(s)
- Hui Xu
- State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment, Tsinghua University, Beijing 100084, China
| | - Jiali Chang
- State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment, Tsinghua University, Beijing 100084, China
| | - Han Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment, Tsinghua University, Beijing 100084, China
| | - Yancheng Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment, Tsinghua University, Beijing 100084, China
| | - Xiaoyuan Zhang
- State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment, Tsinghua University, Beijing 100084, China
| | - Peng Liang
- State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment, Tsinghua University, Beijing 100084, China
| | - Xia Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment, Tsinghua University, Beijing 100084, China.
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35
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Joicy A, Song YC, Yu H, Chae KJ. Nitrite and nitrate as electron acceptors for bioelectrochemical ammonium oxidation under electrostatic field. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 250:109517. [PMID: 31545180 DOI: 10.1016/j.jenvman.2019.109517] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 08/14/2019] [Accepted: 09/02/2019] [Indexed: 06/10/2023]
Abstract
Bioelectrochemical ammonium oxidation with nitrite and nitrate as electron acceptors was investigated in bulk solution exposed to electrostatic field. In a bioelectrochemical reactor, electroactive nitrogen removal bacteria including ammonium oxidizing exoelectrogens (AOE) and denitrifying electrotrophs (DNE) were enriched by electrostatic field of 0.2 V/cm in a bulk solution containing nitrite, nitrate, and ammonium. Ammonium was oxidized simultaneously with decreases in nitrite and nitrate as electron acceptors due to direct interspecies electron transfer between AOE and DNE. The specific ammonium oxidation rate was 48 mg NH4-N/g VSS.d when nitrate fraction was 1/3 in the electron acceptor composed of nitrite and nitrate. The specific ammonium oxidation rate gradually decreased with increasing nitrate fraction. However, it was still 24 mg NH4-N/g VSS.d when nitrate was the only electron acceptor. This indicates that nitrate can be used as an electron acceptor for bioelectrochemical ammonium oxidation, although it is a less effective than nitrite. This finding provides an advantage that strict nitritation which selectively produces nitrite from ammonium can be avoided when treating ammonia-rich wastewater in a bioelectrochemical reactor.
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Affiliation(s)
- Anna Joicy
- Department of Environmental Engineering, Korea Maritime and Ocean University, Busan, 49112, South Korea
| | - Young-Chae Song
- Department of Environmental Engineering, Korea Maritime and Ocean University, Busan, 49112, South Korea.
| | - Hanchao Yu
- Department of Environmental Engineering, Korea Maritime and Ocean University, Busan, 49112, South Korea
| | - Kyu-Jung Chae
- Department of Environmental Engineering, Korea Maritime and Ocean University, Busan, 49112, South Korea
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36
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Lei Y, Sun D, Dang Y, Feng X, Huo D, Liu C, Zheng K, Holmes DE. Metagenomic analysis reveals that activated carbon aids anaerobic digestion of raw incineration leachate by promoting direct interspecies electron transfer. WATER RESEARCH 2019; 161:570-580. [PMID: 31238222 DOI: 10.1016/j.watres.2019.06.038] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 06/13/2019] [Accepted: 06/14/2019] [Indexed: 06/09/2023]
Abstract
The raw fresh leachate from municipal solid waste (MSW) incineration plants contains high concentrations of volatile fatty acids (VFAs), ammonia and metals, all compounds that severely limit anaerobic digestion treatment efficiencies. These inhibitory compounds make reactor systems unstable, causing reactor start-up periods to take more than 100 days, even when the leachate is diluted significantly. In this study, granular activated carbon (GAC) was incorporated into a bioreactor fed with raw incineration leachate. Addition of GAC allowed direct treatment of raw incineration leachate without any start-up acclimation period, while the non-amended control reactor soured immediately and collapsed within 17 days. When hydraulic retention time (HRT) of the GAC-amended reactor was stepwise decreased to increase organic loading rates (OLR) to 25.0 kgCOD/(m3·d), COD removal efficiencies remained stable at >90%. Metagenomic analysis of the GAC-amended reactor revealed that Geobacter and Methanosarcina, species known to participate in direct interspecies electron transfer (DIET), were more abundant in the GAC-amended reactor than the seed sludge. In addition, the abundance of genes coding for proteins thought to be involved in DIET such as electrically conductive pili and the outer membrane c-type cytochrome, OmcS, increased significantly, while genes involved in fermentation, and nitrate (narG) and sulfate (dsrA) reduction dropped significantly as the experiment progressed. These results are significant because this is the first detailed investigation into the metabolic capabilities of microbial communities involved in efficient treatment of raw incineration leachate within biomethanogenic reactors that did not require a long start-up period.
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Affiliation(s)
- Yuqing Lei
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China; Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China
| | - Dezhi Sun
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China.
| | - Yan Dang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China.
| | - Xianlu Feng
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Da Huo
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Chuanqi Liu
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Kun Zheng
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Dawn E Holmes
- Department of Physical and Biological Sciences, Western New England University, 1215 Wilbraham Rd, Springfield, MA, 01119, United States
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37
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Liu X, Zhan J, Jing X, Zhou S, Lovley DR. A pilin chaperone required for the expression of electrically conductive
Geobacter sulfurreducens
pili. Environ Microbiol 2019; 21:2511-2522. [DOI: 10.1111/1462-2920.14638] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/15/2019] [Accepted: 04/21/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Xing Liu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and EnvironmentFujian Agriculture and Forestry University Fuzhou China
| | - Ji Zhan
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and EnvironmentFujian Agriculture and Forestry University Fuzhou China
| | - Xianyue Jing
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and EnvironmentFujian Agriculture and Forestry University Fuzhou China
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and EnvironmentFujian Agriculture and Forestry University Fuzhou China
| | - Derek R. Lovley
- Department of MicrobiologyUniversity of Massachusetts Amherst Amherst MA USA
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Yang G, Wang J, Zhang H, Jia H, Zhang Y, Gao F. Applying bio-electric field of microbial fuel cell-upflow anaerobic sludge blanket reactor catalyzed blast furnace dusting ash for promoting anaerobic digestion. WATER RESEARCH 2019; 149:215-224. [PMID: 30447526 DOI: 10.1016/j.watres.2018.10.091] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 10/28/2018] [Accepted: 10/30/2018] [Indexed: 06/09/2023]
Abstract
In this study, a novel manner of bio-electric field (BEF) which generated by upflow anaerobic sludge blanket (UASB)-microbial fuel cell (MFC) integrated system facilitated iron-carbon micro-electrolysis in blast furnace dusting ash (BFDA) was proposed for the reinforcement of anaerobic digestion in UASB. The responses of COD removal efficiency and biogas production with (0.1-0.4 V) BEF catalyzed 5 g BFDA(RMFC-5gBFDA-UASB) were much higher than the other tests, and maximum reached 86% and 240 ml/d respectively. Ultra-fast acidogenesis was achieved with 0.3 V BEF supplied to BFDA and the time shortened 94 h compared controlled (RUASB) with RMFC-5gBFDA-UASB. With the electrochemical and microbial community analysis, the redox ability and direct interspecies electron transfer accumulated with BEF catalyzed. The abundance of Firmicutes which could generate bio-hydrogen was highest in RMFC-5gBFDA-UASB (44.58%) compared to RUASB (31.36%) and R5gBFDA-UASB (40.04%). In addition, the structure and morphology variation of BFDA revealed that the synergistic effects of BEF stimulated iron-carbon micro-electrolysis for electron transferring and enhanced the activities of methanogens and acetogens with high relative abundance to biotransform organic compounds, as well as adsorption and precipitation of iron oxides (hematite and magnetite) promoting anaerobic digestion. The MFC-BFDA-UASB integrated system provides a promising and cost-effective way to enhance anaerobic digestion and recycled functionalized waste effectively.
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Affiliation(s)
- Guang Yang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China; State Key Laboratory of Separation Membranes and Membrane Processes, Tianjin Polytechnic University, Tianjin, 300387, China
| | - Jie Wang
- State Key Laboratory of Separation Membranes and Membrane Processes, Tianjin Polytechnic University, Tianjin, 300387, China; School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin, 300387, China.
| | - Hongwei Zhang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China; State Key Laboratory of Separation Membranes and Membrane Processes, Tianjin Polytechnic University, Tianjin, 300387, China.
| | - Hui Jia
- State Key Laboratory of Separation Membranes and Membrane Processes, Tianjin Polytechnic University, Tianjin, 300387, China; School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin, 300387, China
| | - Yang Zhang
- State Key Laboratory of Separation Membranes and Membrane Processes, Tianjin Polytechnic University, Tianjin, 300387, China
| | - Fei Gao
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China; State Key Laboratory of Separation Membranes and Membrane Processes, Tianjin Polytechnic University, Tianjin, 300387, China
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Barua S, Zakaria BS, Lin L, Dhar BR. Shaping microbial communities with conductive carbon fibers to enhance methane productivity and kinetics. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2018.11.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Zhang S, Chang J, Liu W, Pan Y, Cui K, Chen X, Liang P, Zhang X, Wu Q, Qiu Y, Huang X. A novel bioaugmentation strategy to accelerate methanogenesis via adding Geobacter sulfurreducens PCA in anaerobic digestion system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 642:322-326. [PMID: 29906723 DOI: 10.1016/j.scitotenv.2018.06.043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 06/04/2018] [Accepted: 06/04/2018] [Indexed: 06/08/2023]
Abstract
Based on the new syntrophic methanogenesis route via direct interspecies electron transfer (DIET), a novel bioaugmentation method by adding exoelectrogenic Geobacter species to accelerate methanogenesis was developed in this study. Geobacter sulfurreducens PCA, type exoelectrogenic strain of Geobacter species was chosen for the research. To clarify the effect of G. sulfurreducens on methanogenesis, batch tests of CH4 production were carried out. Acetate, the most typical precursor of methanogenesis was chosen as the substrate of batch tests. Amendment of G. sulfurreducens accelerated CH4 production remarkably. The lag phase of CH4 production was shortened, and the maximum CH4 production rate was increased by 78%. Fluorescence in situ hybridization showed that G. sulfurreducens closely gathered with methanogens. For the archaeal communities, the high-throughput sequencing results demonstrated that Methanosaetaceae and Methanobacteriaceae were potential bioaugmented methanogens. We speculated that the accelerated methanogenesis by adding G. sulfurreducens may result from the syntrophic association between G. sulfurreducens and methanogens affiliated with Methanosaetaceae and Methanobacteriaceae. This research provides a new route to enhance methanogenesis through the utilization of G. sulfurreducens. Through this study, the role of Geobacter in the anaerobic engineering and carbon cycling of nature should be paid more attention.
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Affiliation(s)
- Shuo Zhang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Jiali Chang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Wei Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yiran Pan
- School of Resources & Environmental Engineering, Hefei University of Technology, Anhui Province 230009, China
| | - Kangping Cui
- School of Resources & Environmental Engineering, Hefei University of Technology, Anhui Province 230009, China
| | - Xi Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Peng Liang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Xiaoyuan Zhang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Qing Wu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yong Qiu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Xia Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
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Barua S, Zakaria BS, Dhar BR. Enhanced methanogenic co-degradation of propionate and butyrate by anaerobic microbiome enriched on conductive carbon fibers. BIORESOURCE TECHNOLOGY 2018; 266:259-266. [PMID: 29982046 DOI: 10.1016/j.biortech.2018.06.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 06/13/2018] [Accepted: 06/16/2018] [Indexed: 05/10/2023]
Abstract
Recent studies have shown that the addition of conductive materials can promote direct interspecies electron transfer (DIET) between bacteria and methanoarchaea. This study demonstrated that carbon fibers could significantly stimulate methanogenic conversion of propionate and butyrate as co-substrate, while only butyrate was completely degraded in the unamended control bioreactor. In the carbon fibers-amended bioreactor, specific methane production (mL-CH4/g CODInitial) and methanogenesis rate (d-1) increased by around 2.4 and 6.7 times, respectively. Various electroactive bacteria were abundant in the carbon fibers-amended bioreactor, whereas different known fermentative bacteria were abundant in the control. Moreover, carbon fibers substantially increased the abundance of Methanosaeta species. These results suggest that electroactive bacteria could be involved in DIET with Methanosaeta species enabling co-degradation of propionate and butyrate. Additionally, electrical conductivities of the biomass were comparable in both configurations, indicating that carbon fibers were the primary route for DIET.
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Affiliation(s)
- Sajib Barua
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Basem S Zakaria
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Department of Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada.
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Feng Q, Song YC, Yoo K, Kuppanan N, Subudhi S, Lal B. Polarized electrode enhances biological direct interspecies electron transfer for methane production in upflow anaerobic bioelectrochemical reactor. CHEMOSPHERE 2018; 204:186-192. [PMID: 29655112 DOI: 10.1016/j.chemosphere.2018.03.163] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/19/2018] [Accepted: 03/22/2018] [Indexed: 06/08/2023]
Abstract
The influence of polarized electrodes on the methane production, which depends on the sludge concentration, was investigated in upflow anaerobic bioelectrochemical (UABE) reactor. When the polarized electrode was placed in the bottom zone with a high sludge concentration, the methane production was 5.34 L/L.d, which was 53% higher than upflow anaerobic sludge blanket (UASB) reactor. However, the methane production was reduced to 4.34 L/L.d by placing the electrode in the upper zone of the UABE reactor with lower sludge concentration. In the UABE reactor, the methane production was mainly improved by the enhanced biological direct interspecies electron transfer (bDIET) pathway, and the methane production via the electrode was a minor fraction of less than 4% of total methane production. The polarized electrodes that placed in the bottom zone with a high sludge concentration enhance the bDIET for methane production in the UABE reactor and greatly improve the methane production.
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Affiliation(s)
- Qing Feng
- School of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
| | - Young-Chae Song
- Department of Environmental Engineering, Korea Maritime and Ocean University, Busan, 49112, South Korea.
| | - Kyuseon Yoo
- Department of Civil & Environmental Engineering, Jeonju University, Jeonju 55069, South Korea
| | - Nanthakumar Kuppanan
- Environmental and Industrial Biotechnology Division, The Energy and Resources Institute, New Delhi 110003, India
| | - Sanjukta Subudhi
- Environmental and Industrial Biotechnology Division, The Energy and Resources Institute, New Delhi 110003, India
| | - Banwari Lal
- Environmental and Industrial Biotechnology Division, The Energy and Resources Institute, New Delhi 110003, India
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Wang L, Liu T, Sun H, Zhou Q. Transesterification of para-hydroxybenzoic acid esters (parabens) in the activated sludge. JOURNAL OF HAZARDOUS MATERIALS 2018; 354:145-152. [PMID: 29751170 DOI: 10.1016/j.jhazmat.2018.04.077] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 04/27/2018] [Accepted: 04/29/2018] [Indexed: 05/27/2023]
Abstract
Hydrolysis is generally considered as the main pathway for the degradation of ester-type pollutants in aquatic environments. In this study, we found that when methanol or ethanol presented as the external carbon in the activated sludge, transesterification is very important for the degradation of para-hydroxybenzoic acid esters (parabens). In the activated sludge solutions with 1% methanol added, contribution of transesterification to the degradation of the propyl substituted paraben (PrP) and ethyl substituted paraben (EtP) accounted for 46% and 83%, respectively, in the early stage of the reaction. This indicates that in aquatic environments with alcohols presence, parabens prefer to form small molecule homologues than hydrolysis to acid. The predominant transesterification in the activated sludge is related to enzyme preference. Amano lipase from Pseudomonas fluorescens was verified to catalyze hydrolysis and transesterification of parabens, while the latter was dominant in water solution with 1% methanol or ethanol. Considering the common application of small molecular alcohols as the external carbon sources in wastewater treatment plants, transesterification might be an important pathway for the degradation of parabens pollutants in these engineering aquatic environments.
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Affiliation(s)
- Lei Wang
- Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria / Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering at Nankai University, Tianjin, 300350, China.
| | - Tianzhen Liu
- Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria / Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering at Nankai University, Tianjin, 300350, China
| | - Hongwen Sun
- Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria / Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering at Nankai University, Tianjin, 300350, China
| | - Qixing Zhou
- Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria / Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering at Nankai University, Tianjin, 300350, China
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Ueki T, Nevin KP, Woodard TL, Aklujkar MA, Holmes DE, Lovley DR. Construction of a Geobacter Strain With Exceptional Growth on Cathodes. Front Microbiol 2018; 9:1512. [PMID: 30057572 PMCID: PMC6053493 DOI: 10.3389/fmicb.2018.01512] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 06/18/2018] [Indexed: 12/13/2022] Open
Abstract
Insoluble extracellular electron donors are important sources of energy for anaerobic respiration in biogeochemical cycling and in diverse practical applications. The previous lack of a genetically tractable model microorganism that could be grown to high densities under anaerobic conditions in pure culture with an insoluble extracellular electron donor has stymied efforts to better understand this form of respiration. We report here on the design of a strain of Geobacter sulfurreducens, designated strain ACL, which grows as thick (ca. 35 μm) confluent biofilms on graphite cathodes poised at -500 mV (versus Ag/AgCl) with fumarate as the electron acceptor. Sustained maximum current consumption rates were >0.8 A/m2, which is >10-fold higher than the current consumption of the wild-type strain. The improved function on the cathode was achieved by introducing genes for an ATP-dependent citrate lyase, completing the complement of enzymes needed for a reverse TCA cycle for the synthesis of biosynthetic precursors from carbon dioxide. Strain ACL provides an important model organism for elucidating the mechanisms for effective anaerobic growth with an insoluble extracellular electron donor and may offer unique possibilities as a chassis for the introduction of synthetic metabolic pathways for the production of commodities with electrons derived from electrodes.
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Affiliation(s)
- Toshiyuki Ueki
- Morrill Science Center IV, Department of Microbiology, University of Massachusetts, Amherst, MA, United States
| | - Kelly P Nevin
- Morrill Science Center IV, Department of Microbiology, University of Massachusetts, Amherst, MA, United States
| | - Trevor L Woodard
- Morrill Science Center IV, Department of Microbiology, University of Massachusetts, Amherst, MA, United States
| | - Muktak A Aklujkar
- Morrill Science Center IV, Department of Microbiology, University of Massachusetts, Amherst, MA, United States
| | - Dawn E Holmes
- Morrill Science Center IV, Department of Microbiology, University of Massachusetts, Amherst, MA, United States.,Department of Physical and Biological Sciences, Western New England University, Springfield, MA, United States
| | - Derek R Lovley
- Morrill Science Center IV, Department of Microbiology, University of Massachusetts, Amherst, MA, United States
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Geobacter Strains Expressing Poorly Conductive Pili Reveal Constraints on Direct Interspecies Electron Transfer Mechanisms. mBio 2018; 9:mBio.01273-18. [PMID: 29991583 PMCID: PMC6050967 DOI: 10.1128/mbio.01273-18] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cytochrome-to-cytochrome electron transfer and electron transfer along conduits of multiple extracellular magnetite grains are often proposed as strategies for direct interspecies electron transfer (DIET) that do not require electrically conductive pili (e-pili). However, physical evidence for these proposed DIET mechanisms has been lacking. To investigate these possibilities further, we constructed Geobacter metallireducens strain Aro-5, in which the wild-type pilin gene was replaced with the aro-5 pilin gene that was previously shown to yield poorly conductive pili in Geobacter sulfurreducens strain Aro-5. G. metallireducens strain Aro-5 did not reduce Fe(III) oxide and produced only low current densities, phenotypes consistent with expression of poorly conductive pili. Like G. sulfurreducens strain Aro-5, G. metallireducens strain Aro-5 displayed abundant outer surface cytochromes. Cocultures initiated with wild-type G. metallireducens as the electron-donating strain and G. sulfurreducens strain Aro-5 as the electron-accepting strain grew via DIET. However, G. metallireducens Aro-5/G. sulfurreducens wild-type cocultures did not. Cocultures initiated with the Aro-5 strains of both species grew only when amended with granular activated carbon (GAC), a conductive material known to be a conduit for DIET. Magnetite could not substitute for GAC. The inability of the two Aro-5 strains to adapt for DIET in the absence of GAC suggests that there are physical constraints on establishing DIET solely through cytochrome-to-cytochrome electron transfer or along chains of magnetite. The finding that DIET is possible with electron-accepting partners that lack highly conductive pili greatly expands the range of potential electron-accepting partners that might participate in DIET.IMPORTANCE DIET is thought to be an important mechanism for interspecies electron exchange in natural anaerobic soils and sediments in which methane is either produced or consumed, as well as in some photosynthetic mats and anaerobic digesters converting organic wastes to methane. Understanding the potential mechanisms for DIET will not only aid in modeling carbon and electron flow in these geochemically significant environments but will also be helpful for interpreting meta-omic data from as-yet-uncultured microbes in DIET-based communities and for designing strategies to promote DIET in anaerobic digesters. The results demonstrate the need to develop a better understanding of the diversity of types of e-pili in the microbial world to identify potential electron-donating partners for DIET. Novel methods for recovering as-yet-uncultivated microorganisms capable of DIET in culture will be needed to further evaluate whether DIET is possible without e-pili in the absence of conductive materials such as GAC.
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Enhanced redox conductivity and enriched Geobacteraceae of exoelectrogenic biofilms in response to static magnetic field. Appl Microbiol Biotechnol 2018; 102:7611-7621. [DOI: 10.1007/s00253-018-9158-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 05/01/2018] [Accepted: 06/05/2018] [Indexed: 12/26/2022]
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Syntrophic growth with direct interspecies electron transfer between pili-free Geobacter species. ISME JOURNAL 2018; 12:2142-2151. [PMID: 29875437 DOI: 10.1038/s41396-018-0193-y] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 02/08/2018] [Accepted: 03/12/2018] [Indexed: 02/04/2023]
Abstract
Direct interspecies electron transfer (DIET) may prevail in microbial communities that show methanogenesis and anaerobic methane oxidation and can be an electron source to support anaerobic photosynthesis. Previous mutagenic studies on cocultures of defined Geobacter species indicate that both conductive pili and extracellular cytochromes are essential for DIET. However, the actual functional role of the pili in DIET is uncertain, as the pilus mutation strategy used in these studies affected the extracellular cytochrome profile. Here we repressed the function of pili by deleting the pilus polymerization motor PilB in both Geobacter species. The PilB mutation inhibited the pilus assembly but did not alter the pattern of extracellular cytochromes. We report that the two pilus-free Geobacter species can form aggregates and grow syntrophically with DIET. The results demonstrate that the Gmet_2896 cytochrome of Geobacter metallireducens plays a key role in DIET and that conductive pili are not necessary to facilitate DIET in cocultures of Geobacter species, and they suggest cytochromes by themselves can meditate DIET, deepening the understanding of DIET.
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Zhang Z, Gao P, Cheng J, Liu G, Zhang X, Feng Y. Enhancing anaerobic digestion and methane production of tetracycline wastewater in EGSB reactor with GAC/NZVI mediator. WATER RESEARCH 2018; 136:54-63. [PMID: 29494896 DOI: 10.1016/j.watres.2018.02.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 01/18/2018] [Accepted: 02/12/2018] [Indexed: 05/12/2023]
Abstract
Packing nano mediators into anaerobic system is an attractive technology to strengthen refractory pollutant removal and methane production from wastewater, but is limited by the drawbacks such as easy loss and poor mass transfer. In this study, GAC/NZVI mediator was added into EGSB reactor to investigate the enhancement effects and mechanism for anaerobic digestion of tetracycline wastewater and its impacts on microbial community structure. The results indicated that GAC/NZVI could enhance COD and TOC removal by 12.1% and 10.3%, while have no evident influence on tetracycline removal and sulfide production. The biogas production and methane content were increased by 21.2% and 26.9%, respectively. GAC/NZVI addition resulted in formation of densely packed aggregates, and evidently increased the electrical conductivity and EPS content in sludge. Fe content in sludge was 20.43% with the loss of only 5.4% during 34 d operation. Microbial community analysis revealed that GAC/NZVI addition could both increase the Chao 1 richness index and Shannon diversity index of bacteria and archaea. It was notable that total methanogens contents increased from 74.7% to 81.74% at genera level, resulting in higher methane production, while Treponema increase might promote the degradation of tetracycline and its metabolite, leading to higher COD removal.
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Affiliation(s)
- Zhaohan Zhang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin 150090, China
| | - Peng Gao
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin 150090, China; School of Atmospheric Sciences, Sun Yat-sen University, 135 West Xingang Road, Guangzhou 510275 Guangdong, China.
| | - Jiaqi Cheng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin 150090, China
| | - Guohong Liu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin 150090, China
| | - Xiaoqi Zhang
- College of Resources and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Yujie Feng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No73, Huanghe Road, Nangang District, Harbin 150090, China.
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Wang D, Han Y, Han H, Li K, Xu C, Zhuang H. New insights into enhanced anaerobic degradation of Fischer-Tropsch wastewater with the assistance of magnetite. BIORESOURCE TECHNOLOGY 2018; 257:147-156. [PMID: 29499496 DOI: 10.1016/j.biortech.2018.02.084] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/16/2018] [Accepted: 02/17/2018] [Indexed: 06/08/2023]
Abstract
In this study, magnetite (Fe3O4), as the typical conductive material, was supplemented in anaerobic sequential batch reactor (ASBR) with the attempt to enhance pollutants removal and methane production during Fischer-Tropsch wastewater treatment. The results showed that COD removal efficiency and cumulative methane production with the addition of optimum magnetite dosage (0.4 g) were as high as 84.3 ± 2.0% and 7.46 ± 0.24 L, which were higher than other test groups (0, 0.2 and 0.6 g). Furthermore, the combination of high-throughput 16S rRNA gene pyrosequencing and metagenomic analysis in this study further confirmed that the Geobacter and Methanosaeta species were specially enriched in bacterial and archaeal community at the optimum magnetite dosage, suggesting that magnetite-mediated direct interspecies electron transfer (DIET) between Geobacter and Methanosaeta species was likely a crucial reason to promote syntrophic metabolism of propionic acid and butyric acid, and further enhance final methanogenesis.
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Affiliation(s)
- Dexin Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; Institute of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China
| | - Yuxing Han
- School of Engineering, South China Agriculture University, Guangzhou 510642, China
| | - Hongjun Han
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Kun Li
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Chunyan Xu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Haifeng Zhuang
- Key Laboratory of Recycling and Eco-treatment of Waste Biomass of Zhejiang Province, Zhejiang University of Science and Technology, Hangzhou 310023, China
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Li H, Han K, Li Z, Zhang J, Li H, Huang Y, Shen L, Li Q, Wang Y. Performance, granule conductivity and microbial community analysis of upflow anaerobic sludge blanket (UASB) reactors from mesophilic to thermophilic operation. Biochem Eng J 2018. [DOI: 10.1016/j.bej.2018.01.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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