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Ferreira MR, Morgado L, Salgueiro CA. Periplasmic electron transfer network in Geobacter sulfurreducens revealed by biomolecular interaction studies. Protein Sci 2024; 33:e5082. [PMID: 38935664 PMCID: PMC11210610 DOI: 10.1002/pro.5082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 06/29/2024]
Abstract
Multiheme cytochromes located in different compartments are crucial for extracellular electron transfer in the bacterium Geobacter sulfurreducens to drive important environmental processes and biotechnological applications. Recent studies have unveiled that for particular sets of electron terminal acceptors, discrete respiratory pathways selectively recruit specific cytochromes from both the inner and outer membranes. However, such specificity was not observed for the abundant periplasmic cytochromes, namely the triheme cytochrome family PpcA-E. In this work, the distinctive NMR spectroscopic signatures of these proteins in different redox states were explored to monitor pairwise interactions and electron transfer reactions between each pair of cytochromes. The results showed that the five proteins interact transiently and can exchange electrons between each other revealing intra-promiscuity within the members of this family. This discovery is discussed in the light of the establishment of an effective electron transfer network by this pool of cytochromes. This network is advantageous to the bacteria as it enables the maintenance of the functional working potential redox range within the cells.
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Affiliation(s)
- Marisa R. Ferreira
- Associate Laboratory i4HB – Institute for Health and Bioeconomy, NOVA School of Science and TechnologyUniversidade NOVA de LisboaCaparicaPortugal
- UCIBIO – Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and TechnologyUniversidade NOVA de LisboaCaparicaPortugal
| | - Leonor Morgado
- Associate Laboratory i4HB – Institute for Health and Bioeconomy, NOVA School of Science and TechnologyUniversidade NOVA de LisboaCaparicaPortugal
- UCIBIO – Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and TechnologyUniversidade NOVA de LisboaCaparicaPortugal
| | - Carlos A. Salgueiro
- Associate Laboratory i4HB – Institute for Health and Bioeconomy, NOVA School of Science and TechnologyUniversidade NOVA de LisboaCaparicaPortugal
- UCIBIO – Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and TechnologyUniversidade NOVA de LisboaCaparicaPortugal
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2
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Cheng X, Qiu Y, Wang Y, Yu M, Qi J, Ma Z, Sun T, Liu S. Conductive and capacitive network for enriching the exoelectrogens and enhancing the extracellular electron transfer in microbial fuel cells. J Colloid Interface Sci 2024; 664:309-318. [PMID: 38479267 DOI: 10.1016/j.jcis.2024.03.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 02/29/2024] [Accepted: 03/09/2024] [Indexed: 04/07/2024]
Abstract
Although lots of nanomaterials modified anodes have been reported to improve the bacterial attachment and extracellular electron transfer (EET) in microbial fuel cells (MFCs), the lack of a three dimensional (3D) conductive and capacitive network severely limited MFCs performance. In this work, 3D conductive networks derived from mucor mycelia were grown on carbon cloth (CC), and capacitive FeMn phosphides/oxides were further anchored on these 3D networks by electrochemical deposition (denoted as FeMn/CMM@CC) to simultaneously address the above challenges. As a result, the multivalent metal active sites were evenly distributed on 3D conductive network, which favored the enrichment of exoelectrogens, mass transport and EET. Consequently, the as-prepared FeMn/CMM@CC anode displayed accumulated charge of 131.4C/m2, higher than bare CC. Meanwhile, FeMn/CMM@CC anode substantially promoted flavin excretion and the amounts of nano conduits. The abundance of Geobacter was 63 % on bare CC, and greatly increased to 83 % on FeMn/CMM@CC. MFCs equipped by FeMn/CMM@CC anode presented the power density of 3.06 W/m2 and coulombic efficiency (29.9 %), evidently higher than bare CC (1.29 W/m2, 7.3 %), and the daily chemical oxygen demand (COD) removal amount also increased to 92.6 mg/L/d. This work developed a facile method to optimize the abiotic-biotic interface by introducing 3D conductive and capacitive network, which was proved to be a promising strategy to modify macro-porous electrodes.
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Affiliation(s)
- Xusen Cheng
- College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, China
| | - Yunfeng Qiu
- School of Medicine and Health, Harbin Institute of Technology, Harbin 150080, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Yanxia Wang
- School of Medicine and Health, Harbin Institute of Technology, Harbin 150080, China
| | - Miao Yu
- School of Medicine and Health, Harbin Institute of Technology, Harbin 150080, China
| | - Jinteng Qi
- College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, China
| | - Zhuo Ma
- School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001, China
| | - Tiedong Sun
- College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, China.
| | - Shaoqin Liu
- School of Medicine and Health, Harbin Institute of Technology, Harbin 150080, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
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3
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Chen Y, Dong X, Sun Z, Xu C, Zhang X, Qin S, Geng W, Cao H, Zhai B, Li X, Wu N. Potential coupling of microbial methane, nitrogen, and sulphur cycling in the Okinawa Trough cold seep sediments. Microbiol Spectr 2024; 12:e0349023. [PMID: 38690913 PMCID: PMC11237511 DOI: 10.1128/spectrum.03490-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 03/13/2024] [Indexed: 05/03/2024] Open
Abstract
The Okinawa Trough (OT) is a back-arc basin with a wide distribution of active cold seep systems. However, our understanding of the metabolic function of microbial communities in the cold seep sediments of the OT remains limited. In this study, we investigated the vertical profiles of functional genes involved in methane, nitrogen, and sulphur cycling in the cold seep sediments of the OT. Furthermore, we explored the possible coupling mechanisms between these biogeochemical cycles. The study revealed that the majority of genes associated with the nitrogen and sulphur cycles were most abundant in the surface sediment layers. However, only the key genes responsible for sulphur disproportionation (sor), nitrogen fixation (nifDKH), and methane metabolism (mcrABG) were more prevalent within sulfate-methane transition zone (SMTZ). Significant positive correlations (P < 0.05) were observed between functional genes involved in sulphur oxidation, thiosulphate disproportionation with denitrification, and dissimilatory nitrate reduction to ammonium (DNRA), as well as between AOM/methanogenesis and nitrogen fixation, and between sulphur disproportionation and AOM. A genome of Filomicrobium (class Alphaproteobacteria) has demonstrated potential in chemoautotrophic activities, particularly in coupling DNRA and denitrification with sulphur oxidation. Additionally, the characterized sulfate reducers such as Syntrophobacterales have been found to be capable of utilizing nitrate as an electron acceptor. The predominant methanogenic/methanotrophic groups in the OT sediments were identified as H2-dependent methylotrophic methanogens (Methanomassiliicoccales and Methanofastidiosales) and ANME-1a. This study offered a thorough understanding of microbial ecosystems in the OT cold seep sediments, emphasizing their contribution to nutrient cycling.IMPORTANCEThe Okinawa Trough (OT) is a back-arc basin formed by extension within the continental lithosphere behind the Ryukyu Trench arc system. Cold seeps are widespread in the OT. While some studies have explored microbial communities in OT cold seep sediments, their metabolic potential remains largely unknown. In this study, we used metagenomic analysis to enhance comprehension of the microbial community's role in nutrient cycling and proposed hypotheses on the coupling process and mechanisms involved in biogeochemical cycles. It was revealed that multiple metabolic pathways can be performed by a single organism or microbes that interact with each other to carry out various biogeochemical cycling. This data set provided a genomic road map on microbial nutrient cycling in OT sediment microbial communities.
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Affiliation(s)
- Ye Chen
- Key Laboratory of Gas Hydrate, Qingdao Institute of Marine Geology, Ministry of Natural Resources, Qingdao, China
- Laboratory for Marine Mineral Resources, Qingdao Marine Science and Technology Center, Qingdao, China
| | - Xiyang Dong
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Zhilei Sun
- Key Laboratory of Gas Hydrate, Qingdao Institute of Marine Geology, Ministry of Natural Resources, Qingdao, China
- Laboratory for Marine Mineral Resources, Qingdao Marine Science and Technology Center, Qingdao, China
| | - Cuiling Xu
- Key Laboratory of Gas Hydrate, Qingdao Institute of Marine Geology, Ministry of Natural Resources, Qingdao, China
- Laboratory for Marine Mineral Resources, Qingdao Marine Science and Technology Center, Qingdao, China
| | - Xilin Zhang
- Key Laboratory of Gas Hydrate, Qingdao Institute of Marine Geology, Ministry of Natural Resources, Qingdao, China
- Laboratory for Marine Mineral Resources, Qingdao Marine Science and Technology Center, Qingdao, China
| | - Shuangshuang Qin
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, China
| | - Wei Geng
- Key Laboratory of Gas Hydrate, Qingdao Institute of Marine Geology, Ministry of Natural Resources, Qingdao, China
- Laboratory for Marine Mineral Resources, Qingdao Marine Science and Technology Center, Qingdao, China
| | - Hong Cao
- Key Laboratory of Gas Hydrate, Qingdao Institute of Marine Geology, Ministry of Natural Resources, Qingdao, China
- Laboratory for Marine Mineral Resources, Qingdao Marine Science and Technology Center, Qingdao, China
| | - Bin Zhai
- Key Laboratory of Gas Hydrate, Qingdao Institute of Marine Geology, Ministry of Natural Resources, Qingdao, China
- Laboratory for Marine Mineral Resources, Qingdao Marine Science and Technology Center, Qingdao, China
| | - Xuecheng Li
- China Offshore Fugro Geosolutions (Shenzhen)Co.Ltd., Shenzhen, China
| | - Nengyou Wu
- Key Laboratory of Gas Hydrate, Qingdao Institute of Marine Geology, Ministry of Natural Resources, Qingdao, China
- Laboratory for Marine Mineral Resources, Qingdao Marine Science and Technology Center, Qingdao, China
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Rodríguez-Torres LM, Huerta-Miranda GA, Martínez-García AL, Mazón-Montijo DA, Hernández-Eligio A, Miranda-Hernández M, Juárez K. Influence of support materials on the electroactive behavior, structure and gene expression of wild type and GSU1771-deficient mutant of Geobacter sulfurreducens biofilms. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-33612-3. [PMID: 38758442 DOI: 10.1007/s11356-024-33612-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 05/05/2024] [Indexed: 05/18/2024]
Abstract
Geobacter sulfurreducens DL1 is a metal-reducing dissimilatory bacterium frequently used to produce electricity in bioelectrochemical systems (BES). The biofilm formed on electrodes is one of the most important factors for efficient electron transfer; this is possible due to the production of type IV pili and c-type cytochromes that allow it to carry out extracellular electron transfer (EET) to final acceptors. In this study, we analyzed the biofilm formed on different support materials (glass, hematite (Fe2O3) on glass, fluorine-doped tin oxide (FTO) semiconductor glass, Fe2O3 on FTO, graphite, and stainless steel) by G. sulfurreducens DL1 (WT) and GSU1771-deficient strain mutant (Δgsu1771). GSU1771 is a transcriptional regulator that controls the expression of several genes involved in electron transfer. Different approaches and experimental tests were carried out with the biofilms grown on the different support materials including structure analysis by confocal laser scanning microscopy (CLSM), characterization of electrochemical activity, and quantification of relative gene expression by RT-qPCR. The gene expression of selected genes involved in EET was analyzed, observing an overexpression of pgcA, omcS, omcM, and omcF from Δgsu1771 biofilms compared to those from WT, also the overexpression of the epsH gene, which is involved in exopolysaccharide synthesis. Although we observed that for the Δgsu1771 mutant strain, the associated redox processes are similar to the WT strain, and more current is produced, we think that this could be associated with a higher relative expression of certain genes involved in EET and in the production of exopolysaccharides despite the chemical environment where the biofilm develops. This study supports that G. sulfurreducens is capable of adapting to the electrochemical environment where it grows.
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Affiliation(s)
- Luis Miguel Rodríguez-Torres
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001. Col. Chamilpa, 62210, Cuernavaca, Morelos, México
| | - Guillermo Antonio Huerta-Miranda
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001. Col. Chamilpa, 62210, Cuernavaca, Morelos, México
| | - Ana Luisa Martínez-García
- Centro de Investigación en Materiales Avanzados S. C., Subsede Monterrey, Grupo de Investigación DORA-Lab, 66628, Apodaca, N. L, México
- Centro de Investigación e Innovación Tecnológica (CIIT), Grupo de Investigación DORA-Lab, Tecnológico Nacional de México Campus Nuevo León (TECNL), 66629, Apodaca, N. L, México
| | - Dalia Alejandra Mazón-Montijo
- Centro de Investigación en Materiales Avanzados S. C., Subsede Monterrey, Grupo de Investigación DORA-Lab, 66628, Apodaca, N. L, México
- Centro de Investigación e Innovación Tecnológica (CIIT), Grupo de Investigación DORA-Lab, Tecnológico Nacional de México Campus Nuevo León (TECNL), 66629, Apodaca, N. L, México
- Investigadores Por México, CONAHCYT, Ciudad de México, México
| | - Alberto Hernández-Eligio
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001. Col. Chamilpa, 62210, Cuernavaca, Morelos, México
- Investigadores Por México, CONAHCYT, Ciudad de México, México
| | - Margarita Miranda-Hernández
- Instituto de Energías Renovables, Universidad Nacional Autónoma de México, Priv. Xochicalco, 62580, Temixco, Morelos, México
| | - Katy Juárez
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001. Col. Chamilpa, 62210, Cuernavaca, Morelos, México.
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5
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Gupta D, Chen K, Elliott SJ, Nayak DD. MmcA is an electron conduit that facilitates both intracellular and extracellular electron transport in Methanosarcina acetivorans. Nat Commun 2024; 15:3300. [PMID: 38632227 PMCID: PMC11024163 DOI: 10.1038/s41467-024-47564-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 04/05/2024] [Indexed: 04/19/2024] Open
Abstract
Methanogens are a diverse group of Archaea that obligately couple energy conservation to the production of methane. Some methanogens encode alternate pathways for energy conservation, like anaerobic respiration, but the biochemical details of this process are unknown. We show that a multiheme c-type cytochrome called MmcA from Methanosarcina acetivorans is important for intracellular electron transport during methanogenesis and can also reduce extracellular electron acceptors like soluble Fe3+ and anthraquinone-2,6-disulfonate. Consistent with these observations, MmcA displays reversible redox features ranging from -100 to -450 mV versus SHE. Additionally, mutants lacking mmcA have significantly slower Fe3+ reduction rates. The mmcA locus is prevalent in members of the Order Methanosarcinales and is a part of a distinct clade of multiheme cytochromes that are closely related to octaheme tetrathionate reductases. Taken together, MmcA might act as an electron conduit that can potentially support a variety of energy conservation strategies that extend beyond methanogenesis.
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Affiliation(s)
- Dinesh Gupta
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Keying Chen
- Department of Chemistry, Boston University, Boston, MA, USA
| | - Sean J Elliott
- Department of Chemistry, Boston University, Boston, MA, USA
| | - Dipti D Nayak
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
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6
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Portela PC, Shipps CC, Shen C, Srikanth V, Salgueiro CA, Malvankar NS. Widespread extracellular electron transfer pathways for charging microbial cytochrome OmcS nanowires via periplasmic cytochromes PpcABCDE. Nat Commun 2024; 15:2434. [PMID: 38509081 PMCID: PMC10954620 DOI: 10.1038/s41467-024-46192-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 02/19/2024] [Indexed: 03/22/2024] Open
Abstract
Extracellular electron transfer (EET) via microbial nanowires drives globally-important environmental processes and biotechnological applications for bioenergy, bioremediation, and bioelectronics. Due to highly-redundant and complex EET pathways, it is unclear how microbes wire electrons rapidly (>106 s-1) from the inner-membrane through outer-surface nanowires directly to an external environment despite a crowded periplasm and slow (<105 s-1) electron diffusion among periplasmic cytochromes. Here, we show that Geobacter sulfurreducens periplasmic cytochromes PpcABCDE inject electrons directly into OmcS nanowires by binding transiently with differing efficiencies, with the least-abundant cytochrome (PpcC) showing the highest efficiency. Remarkably, this defined nanowire-charging pathway is evolutionarily conserved in phylogenetically-diverse bacteria capable of EET. OmcS heme reduction potentials are within 200 mV of each other, with a midpoint 82 mV-higher than reported previously. This could explain efficient EET over micrometres at ultrafast (<200 fs) rates with negligible energy loss. Engineering this minimal nanowire-charging pathway may yield microbial chassis with improved performance.
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Affiliation(s)
- Pilar C Portela
- Microbial Sciences Institute, Yale University, West Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- UCIBIO - Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Catharine C Shipps
- Microbial Sciences Institute, Yale University, West Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Cong Shen
- Microbial Sciences Institute, Yale University, West Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Vishok Srikanth
- Microbial Sciences Institute, Yale University, West Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Carlos A Salgueiro
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
- UCIBIO - Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
| | - Nikhil S Malvankar
- Microbial Sciences Institute, Yale University, West Haven, CT, USA.
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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Wang GH, Song J, Zhang ZY, Xiao QJ, He S, Zeng TT, Liu YJ, Li SY. Enhanced indigenous consortia for the remediation of uranium-contaminated groundwater by bioaugmentation: Reducing and phosphate-solubilizing consortia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:168954. [PMID: 38042188 DOI: 10.1016/j.scitotenv.2023.168954] [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: 08/23/2023] [Revised: 10/27/2023] [Accepted: 11/26/2023] [Indexed: 12/04/2023]
Abstract
To investigate the strengthening effects and mechanisms of bioaugmentation on the microbial remediation of uranium-contaminated groundwater via bioreduction coupled to biomineralization, two exogenous microbial consortia with reducing and phosphate-solubilizing functions were screened and added to uranium-contaminated groundwater as the experimental groups (group B, reducing consortium added; group C, phosphate-solubilizing consortium added). β-glycerophosphate (GP) was selected to stimulate the microbial community as the sole electron donor and phosphorus source. The results showed that bioaugmentation accelerated the consumption of GP and the proliferation of key functional microbes in groups B and C. In group B, Dysgonomonas, Clostridium_sensu_stricto_11 and Clostridium_sensu_stricto_13 were the main reducing bacteria, and Paenibacillus was the main phosphate-solubilizing bacteria. In group C, the microorganisms that solubilized phosphate were mainly unclassified_f_Enterobacteriaceae. Additionally, bioaugmentation promoted the formation of unattached precipitates and alleviated the inhibitory effect of cell surface precipitation on microbial metabolism. As a result, the formation rate of U-phosphate precipitates and the removal rates of aqueous U(VI) in both groups B and C were elevated significantly after bioaugmentation. The U(VI) removal rate was poor in the control group (group A, with only an indigenous consortium). Propionispora, Sporomusa and Clostridium_sensu_stricto_11 may have played an important role in the removal of uranium in group A. Furthermore, the addition of a reducing consortium promoted the reduction of U(VI) to U(IV), and immobilized uranium existed in the form of U(IV)-phosphate and U(VI)-phosphate precipitates in group B. In contrast, U was present mainly as U(VI)-phosphate precipitates in groups A and C. Overall, bioaugmentation with an exogenous consortium resulted in the rapid removal of uranium from groundwater and the formation of U-phosphate minerals and served as an effective strategy for improving the treatment of uranium-contaminated groundwater in situ.
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Affiliation(s)
- Guo-Hua Wang
- School of Civil Engineering, University of South China, Hengyang 421001, China; Hunan Province Key Laboratory of Pollution Control and Resource Reuse Technology, University of South China, Hengyang 421001, China
| | - Jian Song
- School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Zhi-Yue Zhang
- School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Quan-Jin Xiao
- School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Shan He
- School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Tao-Tao Zeng
- School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Ying-Jiu Liu
- School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Shi-You Li
- School of Civil Engineering, University of South China, Hengyang 421001, China; Hunan Province Key Laboratory of Pollution Control and Resource Reuse Technology, University of South China, Hengyang 421001, China; Key Discipline Laboratory for National Defense of Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, China.
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8
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Yang G, Lin C, Hou T, Wu X, Fang Y, Yao S, Zhuang L, Yuan Y. The survival strategy of direct interspecies electron transfer-capable coculture under electron donor-limited environments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168223. [PMID: 37926263 DOI: 10.1016/j.scitotenv.2023.168223] [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: 07/14/2023] [Revised: 10/08/2023] [Accepted: 10/28/2023] [Indexed: 11/07/2023]
Abstract
Direct interspecies electron transfer (DIET) has been considered as an effective mechanism for interspecies electron exchange in microbial syntrophy. Understanding DIET-capable syntrophic associations under energy-limited environments is important because these conditions more closely approximate those found in natural subsurface environments than in the batch cultures in the laboratory. This study, investigated the metabolic dynamics and electron transfer mechanisms in DIET-capable syntrophic coculture of Geobacter metallireducens and Geobacter sulfurreducens under electron donor-limited condition. The wild-coculture and the mutant-coculture with a citrate synthase-deficient G. sulfurreducens exhibited similar rates of syntrophic metabolism under ethanol-limited and ethanol-replete conditions. Transcriptomic analyses revealed that, in the mutant-coculture in which interspecies electron exchange was the sole electron source for G. sulfurreducens, the transcription of genes associated with uptake hydrogenase in G. sulfurreducens were significantly repressed and thus DIET tended to be the preferred mode of interspecies electron exchange under electron donor-limited condition. To overcome electron donor limitation, c-type cytochromes in the coculture actively moved from outer membrane to extracellular environment, potentially via increased secretion of outer-membrane vesicles. These results suggested a preferred electron transfer mechanism for DIET-capable syntrophic communities' survival in the electron donor-limited environments, providing valuable insights into the biogeochemical processes mediated by DIET in natural and engineered environments.
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Affiliation(s)
- Guiqin Yang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China
| | - Canfen Lin
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China
| | - Tiqun Hou
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China
| | - Xian Wu
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China
| | - Yanlun Fang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China
| | - Sijie Yao
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China
| | - Li Zhuang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China.
| | - Yong Yuan
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
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9
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Li C, Hu S, Ji C, Yi K, Yang W. Insight into the Pseudocapacitive Behavior of Electroactive Biofilms in Response to Dynamic-Controlled Electron Transfer and Metabolism Kinetics for Current Generation in Water Treatment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:19891-19901. [PMID: 38000046 DOI: 10.1021/acs.est.3c04771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2023]
Abstract
Electroactive biofilms (EBs) engage in complex electron transfer and storage processes involving intracellular and extracellular mediators with temporary electron storage capabilities. Consequently, electroactive biofilms exhibit pseudocapacitive behaviors during substrate degradation processes. However, comprehensive systematic research in this area has been lacking. This study demonstrated that the pseudocapacitive property was an intrinsic characteristic of EBs. This property represents dynamic-controlled electron transfer and is critical in current generation, unlike noncapacitive responses. Nontransient charge and discharge experiments revealed a correlation between capacitive charge accumulation and current generation in EBs. Additionally, analysis of substrate degradation suggested that the maximum power density (Pmax) changed with the kinetic constants of COD degradation, with pseudocapacitances of EBs directly proportional to Pmax. The interaction networks of key latent variables were evaluated through partial least-squares path modeling analysis. The results indicated that cytochrome c was closely associated with the formation of pseudocapacitance in EBs. In conclusion, pseudocapacitance can be considered a valuable indicator for assessing the complex electron transfer behavior of EBs. Pseudocapacitive biofilms have the potential to efficiently regulate biological reactions and serve as a promising carbon-neutral and renewable strategy for energy generation and storage. An in-depth understanding of the intrinsic property of pseudocapacitive behavior in EBs can undoubtedly advance the development of this concept in the future.
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Affiliation(s)
- Chao Li
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, PR China
| | - Shaogang Hu
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, PR China
| | - Chengcheng Ji
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, PR China
| | - Kexin Yi
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, PR China
| | - Wulin Yang
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, PR China
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10
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Jaramillo-Rodríguez JB, Vega-Alvarado L, Rodríguez-Torres LM, Huerta-Miranda GA, Hernández-Eligio A, Juarez K. Global transcriptional analysis of Geobacter sulfurreducens gsu1771 mutant biofilm grown on two different support structures. PLoS One 2023; 18:e0293359. [PMID: 37878651 PMCID: PMC10599522 DOI: 10.1371/journal.pone.0293359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 09/28/2023] [Indexed: 10/27/2023] Open
Abstract
Electroactive biofilms formation by the metal-reducing bacterium Geobacter sulfurreducens is a step crucial for bioelectricity generation and bioremediation. The transcriptional regulator GSU1771 controls the expression of essential genes involved in electron transfer and biofilm formation in G. sulfurreducens, with GSU1771-deficient producing thicker and more electroactive biofilms. Here, RNA-seq analyses were conducted to compare the global gene expression patterns of wild-type and Δgsu1771 mutant biofilms grown on non-conductive (glass) and conductive (graphite electrode) materials. The Δgsu1771 biofilm grown on the glass surface exhibited 467 differentially expressed (DE) genes (167 upregulated and 300 downregulated) versus the wild-type biofilm. In contrast, the Δgsu1771 biofilm grown on the graphite electrode exhibited 119 DE genes (79 upregulated and 40 downregulated) versus the wild-type biofilm. Among these DE genes, 67 were also differentially expressed in the Δgsu1771 biofilm grown on glass (56 with the same regulation and 11 exhibiting counter-regulation). Among the upregulated genes in the Δgsu1771 biofilms, we identified potential target genes involved in exopolysaccharide synthesis (gsu1961-63, gsu1959, gsu1972-73, gsu1976-77). RT-qPCR analyses were then conducted to confirm the differential expression of a selection of genes of interest. DNA-protein binding assays demonstrated the direct binding of the GSU1771 regulator to the promoter region of pgcA, pulF, relA, and gsu3356. Furthermore, heme-staining and western blotting revealed an increase in c-type cytochromes including OmcS and OmcZ in Δgsu1771 biofilms. Collectively, our findings demonstrated that GSU1771 is a global regulator that controls extracellular electron transfer and exopolysaccharide synthesis in G. sulfurreducens, which is crucial for electroconductive biofilm development.
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Affiliation(s)
- Juan B. Jaramillo-Rodríguez
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Leticia Vega-Alvarado
- Instituto de Ciencias Aplicadas y Tecnología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, México
| | - Luis M. Rodríguez-Torres
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Guillermo A. Huerta-Miranda
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Alberto Hernández-Eligio
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- Investigador por México, Consejo Nacional de Ciencia y Tecnología, Ciudad de México, México
| | - Katy Juarez
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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11
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Ochiai I, Harada T, Jomori S, Kouzuma A, Watanabe K. Bioaugmentation of microbial electrolysis cells with Geobacter sulfurreducens YM18 for enhanced hydrogen production from starch. BIORESOURCE TECHNOLOGY 2023; 386:129508. [PMID: 37468016 DOI: 10.1016/j.biortech.2023.129508] [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: 06/05/2023] [Revised: 07/12/2023] [Accepted: 07/16/2023] [Indexed: 07/21/2023]
Abstract
Double-chamber microbial electrolysis cells (MECs) were operated using starch-based medium as the anolyte and rice paddy-field soil as the anode inoculum, and hydrogen production from the cathode chamber was examined. In order to enhance current generation and hydrogen production, the anode chamber was bioaugmented with Geobacter sulfurreducens strain YM18, and its effects were evaluated based on the performances of non-bioaugmented controls. Results show that the bioaugmented MEC generated threefold greater current during one-month operation and produced sixfold greater amounts of hydrogen than those of the non-bioaugmented control. Quantitative PCR and metabarcoding analyses confirmed successful colonization of anode surfaces with YM18, suggesting the utility of bioaugmentation with YM18 for enhancing the performance of bioelectrochemical systems, including MECs treating biomass wastes.
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Affiliation(s)
- Itta Ochiai
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Tomoka Harada
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Shinji Jomori
- Advanced Material Engineering Division, Toyota Motor Corporation, Susono, Shizuoka 410-1193, Japan
| | - Atsushi Kouzuma
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Kazuya Watanabe
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
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12
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Zhang X, Joyce GH, Leu AO, Zhao J, Rabiee H, Virdis B, Tyson GW, Yuan Z, McIlroy SJ, Hu S. Multi-heme cytochrome-mediated extracellular electron transfer by the anaerobic methanotroph 'Candidatus Methanoperedens nitroreducens'. Nat Commun 2023; 14:6118. [PMID: 37777538 PMCID: PMC10542353 DOI: 10.1038/s41467-023-41847-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 09/18/2023] [Indexed: 10/02/2023] Open
Abstract
Anaerobic methanotrophic archaea (ANME) carry out anaerobic oxidation of methane, thus playing a crucial role in the methane cycle. Previous genomic evidence indicates that multi-heme c-type cytochromes (MHCs) may facilitate the extracellular electron transfer (EET) from ANME to different electron sinks. Here, we provide experimental evidence supporting cytochrome-mediated EET for the reduction of metals and electrodes by 'Candidatus Methanoperedens nitroreducens', an ANME acclimated to nitrate reduction. Ferrous iron-targeted fluorescent assays, metatranscriptomics, and single-cell imaging suggest that 'Ca. M. nitroreducens' uses surface-localized redox-active cytochromes for metal reduction. Electrochemical and Raman spectroscopic analyses also support the involvement of c-type cytochrome-mediated EET for electrode reduction. Furthermore, several genes encoding menaquinone cytochrome type-c oxidoreductases and extracellular MHCs are differentially expressed when different electron acceptors are used.
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Affiliation(s)
- Xueqin Zhang
- Australian Centre for Water and Environmental Biotechnology (ACWEB), Faculty of Engineering, Architecture and Information Technology, University of Queensland, Brisbane, Australia
| | - Georgina H Joyce
- Centre for Microbiome Research, School of Biomedical Sciences, Queensland University of Technology (QUT), Translational Research Institute, Woolloongabba, Australia
| | - Andy O Leu
- Centre for Microbiome Research, School of Biomedical Sciences, Queensland University of Technology (QUT), Translational Research Institute, Woolloongabba, Australia
| | - Jing Zhao
- Australian Centre for Water and Environmental Biotechnology (ACWEB), Faculty of Engineering, Architecture and Information Technology, University of Queensland, Brisbane, Australia
- Ecological Engineering of Mine Wastes, Sustainable Minerals Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Hesamoddin Rabiee
- Australian Centre for Water and Environmental Biotechnology (ACWEB), Faculty of Engineering, Architecture and Information Technology, University of Queensland, Brisbane, Australia
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD, Australia
- Centre for Future Materials, University of Southern Queensland, Springfield, QLD, Australia
| | - Bernardino Virdis
- Australian Centre for Water and Environmental Biotechnology (ACWEB), Faculty of Engineering, Architecture and Information Technology, University of Queensland, Brisbane, Australia
| | - Gene W Tyson
- Centre for Microbiome Research, School of Biomedical Sciences, Queensland University of Technology (QUT), Translational Research Institute, Woolloongabba, Australia
| | - Zhiguo Yuan
- Australian Centre for Water and Environmental Biotechnology (ACWEB), Faculty of Engineering, Architecture and Information Technology, University of Queensland, Brisbane, Australia
- School of Energy and Environment, City University of Hong Kong, Hong Kong SAR, China
| | - Simon J McIlroy
- Centre for Microbiome Research, School of Biomedical Sciences, Queensland University of Technology (QUT), Translational Research Institute, Woolloongabba, Australia
| | - Shihu Hu
- Australian Centre for Water and Environmental Biotechnology (ACWEB), Faculty of Engineering, Architecture and Information Technology, University of Queensland, Brisbane, Australia.
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13
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Lu Y, Zhang S, Liu Q, Zhong L, Xie Q, Duan A, Yang Z, Liu Q, Zhang Z, Hao J. Nitrobenzene reduction promoted by the integration of carbon nanotubes and Geobacter sulfurreducens. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 325:121444. [PMID: 36921658 DOI: 10.1016/j.envpol.2023.121444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 03/10/2023] [Accepted: 03/11/2023] [Indexed: 06/18/2023]
Abstract
Electron shuttles (ES) can mediate long-distance electron transfer between extracellular respiratory bacteria (ERB) and the surroundings. However, the effects of graphite structure in ES on the extracellular electron transfer (EET) process remain ambiguous. This work investigated the function of graphite structure in the process of nitrobenzene (NB) degradation by Geobacter sulfurreducens PCA, in which highly aromatic carbon nanotubes (CNTs) was studied as a typical ES. The results showed that the addition of 1.5 g L-1 of CNTs improved the NB biodegradation up to 81.2%, plus 18.8% NB loss due to the adsorption property of CNTs, achieving complete removal of 200 μM NB within 9 h. The amendment of CNTs greatly increased the EET rate, indicating that graphite structure exhibited excellent electron shuttle performance. Furthermore, Raman spectrum proved that CNTs obtained better graphite structure after 90 h of cultivation with strain PCA, resulting in higher electrochemical performance. Also, CNTs was perceived as the "Contaminant Reservoir", which alleviated the toxic effect of NB and shortened the distance of EET process. Overall, this work focused on the effects of material graphite structure on the EET process, which enriched the understanding of the interaction between CNTs and ERB, and these results might promote their application in the in-situ bioremediation of nitroaromatic-polluted environment.
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Affiliation(s)
- Yue Lu
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China.
| | - Shoujuan Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China
| | - Qi Liu
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China
| | - Linrui Zhong
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China
| | - Qingqing Xie
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China
| | - Abing Duan
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China.
| | - Zhaohui Yang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China
| | - Qian Liu
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China
| | - Zhiyi Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China
| | - Jingru Hao
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, PR China
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14
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Raya D, Peta V, Bomgni A, Du Do T, Kalimuthu J, Salem DR, Gadhamshetty V, Gnimpieba EZ, Dhiman SS. Classification of bacterial nanowire proteins using Machine Learning and Feature Engineering model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.03.539336. [PMID: 37205598 PMCID: PMC10187271 DOI: 10.1101/2023.05.03.539336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Nanowires (NW) have been extensively studied for Shewanella spp. and Geobacter spp. and are mostly produced by Type IV pili or multiheme c-type cytochrome. Electron transfer via NW is the most studied mechanism in microbially induced corrosion, with recent interest in application in bioelectronics and biosensor. In this study, a machine learning (ML) based tool was developed to classify NW proteins. A manually curated 999 protein collection was developed as an NW protein dataset. Gene ontology analysis of the dataset revealed microbial NW is part of membranal proteins with metal ion binding motifs and plays a central role in electron transfer activity. Random Forest (RF), support vector machine (SVM), and extreme gradient boost (XGBoost) models were implemented in the prediction model and were observed to identify target proteins based on functional, structural, and physicochemical properties with 89.33%, 95.6%, and 99.99% accuracy. Dipetide amino acid composition, transition, and distribution protein features of NW are key important features aiding in the model's high performance.
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15
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Gupta D, Chen K, Elliott SJ, Nayak DD. MmcA is an electron conduit that facilitates both intracellular and extracellular electron transport in Methanosarcina acetivorans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.20.537704. [PMID: 37131651 PMCID: PMC10153276 DOI: 10.1101/2023.04.20.537704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Methanogens are a diverse group of Archaea that couple energy conservation to the production of methane gas. While most methanogens have no alternate mode of energy conservation, strains like Methanosarcina acetivorans are known to also conserve energy by dissimilatory metal reduction (DSMR) in the presence of soluble ferric iron or iron-containing minerals. The ecological ramifications of energy conservation decoupled from methane production in methanogens are substantial, yet the molecular details are poorly understood. In this work, we conducted in vitro and in vivo studies with a multiheme c-type cytochrome (MHC), called MmcA, to establish its role during methanogenesis and DSMR in M. acetivorans. MmcA purified from M. acetivorans can donate electrons to methanophenazine, a membrane-bound electron carrier, to facilitate methanogenesis. In addition, MmcA can also reduce Fe(III) and the humic acid analog anthraquinone-2,6-disulfonate (AQDS) during DSMR. Furthermore, mutants lacking mmcA have slower Fe(III) reduction rates. The redox reactivities of MmcA are consistent with the electrochemical data where MmcA displays reversible redox features ranging from -100 to -450 mV versus SHE. MmcA is prevalent in members of the Order Methanosarcinales but does not belong to a known family of MHCs linked to extracellular electron transfer, bioinformatically, and instead forms a distinct clade that is closely related to octaheme tetrathionate reductases. Taken together, this study shows that MmcA is widespread in methanogens with cytochromes where it acts as an electron conduit to support a variety of energy conservation strategies that extend beyond methanogenesis.
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Affiliation(s)
- Dinesh Gupta
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Keying Chen
- Department of Chemistry, Boston University, Boston, MA, USA
| | | | - Dipti D. Nayak
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
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16
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Wang Z, Hu Y, Dong Y, Shi L, Jiang Y. Enhancing electrical outputs of the fuel cells with Geobacter sulferreducens by overexpressing nanowire proteins. Microb Biotechnol 2023; 16:534-545. [PMID: 36815664 PMCID: PMC9948223 DOI: 10.1111/1751-7915.14128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/19/2022] [Accepted: 07/26/2022] [Indexed: 11/28/2022] Open
Abstract
Protein nanowires are critical electroactive components for electron transfer of Geobacter sulfurreducens biofilm. To determine the applicability of the nanowire proteins in improving bioelectricity production, their genes including pilA, omcZ, omcS and omcT were overexpressed in G. sulfurreducens. The voltage outputs of the constructed strains were higher than that of the control strain with the empty vector (0.470-0.578 vs. 0.355 V) in microbial fuel cells (MFCs). As a result, the power density of the constructed strains (i.e. 1.39-1.58 W m-2 ) also increased by 2.62- to 2.97-fold as compared to that of the control strain. Overexpression of nanowire proteins also improved biofilm formation on electrodes with increased protein amount and thickness of biofilms. The normalized power outputs of the constructed strains were 0.18-0.20 W g-1 that increased by 74% to 93% from that of the control strain. Bioelectrochemical analyses further revealed that the biofilms and MFCs with the constructed strains had stronger electroactivity and smaller internal resistance, respectively. Collectively, these results demonstrate for the first time that overexpression of nanowire proteins increases the biomass and electroactivity of anode-attached microbial biofilms. Moreover, this study provides a new way for enhancing the electrical outputs of MFCs.
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Affiliation(s)
- Zhigao Wang
- Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geosciences, Wuhan, Hubei, China
| | - Yidan Hu
- Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geosciences, Wuhan, Hubei, China.,Hubei Key Laboratory of Wetland Evolution and Eco-Restoration, Wuhan, Hubei, China
| | - Yiran Dong
- Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geosciences, Wuhan, Hubei, China.,Hubei Key Laboratory of Wetland Evolution and Eco-Restoration, Wuhan, Hubei, China.,State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, Hubei, China.,Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan, Hubei, China.,State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, Ministry of Ecology and Environment, China University of Geosciences, Wuhan, Hubei, China
| | - Liang Shi
- Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geosciences, Wuhan, Hubei, China.,State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, Hubei, China.,Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan, Hubei, China.,State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, Ministry of Ecology and Environment, China University of Geosciences, Wuhan, Hubei, China
| | - Yongguang Jiang
- Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geosciences, Wuhan, Hubei, China.,Hubei Key Laboratory of Wetland Evolution and Eco-Restoration, Wuhan, Hubei, China
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17
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Gao Y, Xia L, Yao P, Lee HS. Periodic step polarization accelerates electron recovery by electroactive biofilms (EABs). Biotechnol Bioeng 2023; 120:1545-1556. [PMID: 36782377 DOI: 10.1002/bit.28352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 01/08/2023] [Accepted: 02/09/2023] [Indexed: 02/15/2023]
Abstract
Relatively low rate of electron recovery is one of the factors that limit the advancement of bioelectrochemical systems. Here, new periodic polarizations were investigated with electroactive biofilms (EABs) enriched from activated sludge and Geobacter sulfurreducens biofilms. When representative anode potentials (Ea ) were applied, redox centers with midpoint potentials (Emid ) higher than Ea were identified by localized cyclic voltammetry. The electrons held by these redox centers were accessible when Ea was raised to 0.4 V (vs. Ag/AgCl). New periodic polarizations that discharge at 0.4 V recovered electrons faster than normal periodic and fixed-potential polarizations. The best-performing periodic step polarization accelerated electron recovery by 23%-24% and 12%-76% with EABs and G. sulfurreducens biofilms, respectively, compared to the fixed-potential polarization. Quantitative reverse transcription polymerase chain reaction showed an increased abundance of omcZ mRNA transcripts from G. sulfurreducens after periodic step polarization. Therefore, both the rate of energy recovery by EABs and the performance of bioelectrochemical systems can be enhanced by improving the polarization schemes.
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Affiliation(s)
- Yaohuan Gao
- Institute of Global Environmental Change, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Longfei Xia
- Institute of Global Environmental Change, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Land Engineering Construction Group, Xi'an, Shaanxi, People's Republic of China
| | - Peiru Yao
- Institute of Global Environmental Change, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Hyung-Sool Lee
- Institute for Environmental and Climate Technology, Korea Institute of Energy Technology (KENTECH), Naju-si, Republic of Korea
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18
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Liu JQ, Ma X, Liu DF, Yang CW, Li DB, Min D, Yu HQ. Multiple roles of released c-type cytochromes in tuning electron transport and physiological status of Geobacter sulfurreducens. Biotechnol Bioeng 2023; 120:1346-1356. [PMID: 36779277 DOI: 10.1002/bit.28351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/13/2023] [Accepted: 02/09/2023] [Indexed: 02/14/2023]
Abstract
Dissimilatory metal-reducing bacteria (DMRB) can transfer electrons to extracellular insoluble electron acceptors and play important roles in geochemical cycling, biocorrosion, environmental remediation, and bioenergy generation. c-type cytochromes (c-Cyts) are synthesized by DMRB and usually transported to the cell surface to form modularized electron transport conduits through protein assembly, while some of them are released as extracellularly free-moving electron carriers in growth to promote electron transport. However, the type of these released c-Cyts, the timing of their release, and the functions they perform have not been unrevealed yet. In this work, after characterizing the types of c-Cyts released by Geobacter sulfurreducens under a variety of cultivation conditions, we found that these c-Cyts accumulated up to micromolar concentrations in the surrounding medium and conserved their chemical activities. Further studies demonstrated that the presence of c-Cyts accelerated the process of microbial extracellular electron transfer and mediated long-distance electron transfer. In particular, the presence of c-Cyts promoted the microbial respiration and affected the physiological state of the microbial community. In addition, c-Cyts were observed to be adsorbed on the surface of insoluble electron acceptors and modify electron acceptors. These results reveal the overlooked multiple roles of the released c-Cyts in acting as public goods, delivering electrons, modifying electron acceptors, and even regulating bacterial community structure in natural and artificial environments.
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Affiliation(s)
- Jia-Qi Liu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei, China
| | - Xin Ma
- School of Life Sciences, University of Science & Technology of China, Hefei, China
| | - Dong-Feng Liu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei, China
| | - Chuan-Wang Yang
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei, China
| | - Dao-Bo Li
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei, China.,Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Di Min
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei, China
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei, China.,School of Life Sciences, University of Science & Technology of China, Hefei, China
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19
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Tikhonova TV, Osipov EM, Dergousova NI, Boyko KM, Elizarov IM, Gavrilov SN, Khrenova MG, Robb FT, Solovieva AY, Bonch-Osmolovskaya EA, Popov VO. Extracellular Fe(III) reductase structure reveals a modular organization enabling S-layer insertion and electron transfer to insoluble substrates. Structure 2023; 31:174-184.e3. [PMID: 36630959 DOI: 10.1016/j.str.2022.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/16/2022] [Accepted: 12/14/2022] [Indexed: 01/12/2023]
Abstract
The thermophilic anaerobic Gram-positive bacterium Carboxydothermus ferrireducens utilizes insoluble Fe(III) oxides as electron acceptors in respiratory processes using an extracellular 11-heme cytochrome c OmhA as a terminal reductase. OmhA is able to transfer electrons to soluble and insoluble Fe(III) compounds, substrates of multiheme oxidoreductases, and soluble electron shuttles. The crystal structure of OmhA at 2.5 Å resolution shows that it consists of two functionally distinct parts: the cytochrome с electron transfer and the S-layer binding domains. Nonaheme C-terminal subdomain of the cytochrome с domain is structurally similar to the extracellular multiheme cytochrome OcwA from the metal-reducing Gram-positive bacterium "Thermincola potens." S-layer binding domain of OmhA is responsible for interaction with the S-layer that surrounds the Carboxydothermus ferrireducens cell envelope. The structural foundations enabling the embedding of extracellular multiheme cytochromes to the S-layer of a Gram-positive-type cell wall and putative electron transfer pathways to insoluble minerals are discussed.
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Affiliation(s)
- Tamara V Tikhonova
- Research Center of Biotechnology of the Russian Academy of Sciences, 33 Leninsky Prospect, Building 1, Moscow 119071, Russian Federation
| | - Evgenii M Osipov
- Research Center of Biotechnology of the Russian Academy of Sciences, 33 Leninsky Prospect, Building 1, Moscow 119071, Russian Federation; Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49, Leuven 3000, Belgium
| | - Natalia I Dergousova
- Research Center of Biotechnology of the Russian Academy of Sciences, 33 Leninsky Prospect, Building 1, Moscow 119071, Russian Federation
| | - Konstantin M Boyko
- Research Center of Biotechnology of the Russian Academy of Sciences, 33 Leninsky Prospect, Building 1, Moscow 119071, Russian Federation
| | - Ivan M Elizarov
- Research Center of Biotechnology of the Russian Academy of Sciences, 33 Leninsky Prospect, Building 1, Moscow 119071, Russian Federation
| | - Sergey N Gavrilov
- Research Center of Biotechnology of the Russian Academy of Sciences, 33 Leninsky Prospect, Building 1, Moscow 119071, Russian Federation
| | - Maria G Khrenova
- Research Center of Biotechnology of the Russian Academy of Sciences, 33 Leninsky Prospect, Building 1, Moscow 119071, Russian Federation; Department of Chemistry, Lomonosov Moscow State University, 1 Lenin Hills, Building 3, Moscow 119991, Russian Federation
| | - Frank T Robb
- Institute of Marine and Environmental Technology, Center for Environmental Science, University of Maryland, 701 E. Pratt Street, Baltimore, MD 21202, USA
| | - Anastasia Y Solovieva
- Research Center of Biotechnology of the Russian Academy of Sciences, 33 Leninsky Prospect, Building 1, Moscow 119071, Russian Federation
| | - Elizaveta A Bonch-Osmolovskaya
- Research Center of Biotechnology of the Russian Academy of Sciences, 33 Leninsky Prospect, Building 1, Moscow 119071, Russian Federation; Department of Biology, Lomonosov Moscow State University, 1 Lenin Hills, Building 12, Moscow 119991, Russian Federation
| | - Vladimir O Popov
- Research Center of Biotechnology of the Russian Academy of Sciences, 33 Leninsky Prospect, Building 1, Moscow 119071, Russian Federation; Department of Biology, Lomonosov Moscow State University, 1 Lenin Hills, Building 12, Moscow 119991, Russian Federation.
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20
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Gu Y, Guberman-Pfeffer MJ, Srikanth V, Shen C, Giska F, Gupta K, Londer Y, Samatey FA, Batista VS, Malvankar NS. Structure of Geobacter cytochrome OmcZ identifies mechanism of nanowire assembly and conductivity. Nat Microbiol 2023; 8:284-298. [PMID: 36732469 PMCID: PMC9999484 DOI: 10.1038/s41564-022-01315-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 12/20/2022] [Indexed: 02/04/2023]
Abstract
OmcZ nanowires produced by Geobacter species have high electron conductivity (>30 S cm-1). Of 111 cytochromes present in G. sulfurreducens, OmcZ is the only known nanowire-forming cytochrome essential for the formation of high-current-density biofilms that require long-distance (>10 µm) extracellular electron transport. However, the mechanisms underlying OmcZ nanowire assembly and high conductivity are unknown. Here we report a 3.5-Å-resolution cryogenic electron microscopy structure for OmcZ nanowires. Our structure reveals linear and closely stacked haems that may account for conductivity. Surface-exposed haems and charge interactions explain how OmcZ nanowires bind to diverse extracellular electron acceptors and how organization of nanowire network re-arranges in different biochemical environments. In vitro studies explain how G. sulfurreducens employ a serine protease to control the assembly of OmcZ monomers into nanowires. We find that both OmcZ and serine protease are widespread in environmentally important bacteria and archaea, thus establishing a prevalence of nanowire biogenesis across diverse species and environments.
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Affiliation(s)
- Yangqi Gu
- Microbial Sciences Institute, Yale University, West Haven, CT, USA.
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA.
- PNAC division, Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
| | - Matthew J Guberman-Pfeffer
- Microbial Sciences Institute, Yale University, West Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Vishok Srikanth
- Microbial Sciences Institute, Yale University, West Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Cong Shen
- Microbial Sciences Institute, Yale University, West Haven, CT, USA
- Department of Microbiology, Yale University, New Haven, CT, USA
| | - Fabian Giska
- Department of Cell Biology, Yale University, New Haven, CT, USA
- Nanobiology Institute, Yale University, West Haven, CT, USA
| | - Kallol Gupta
- Department of Cell Biology, Yale University, New Haven, CT, USA
- Nanobiology Institute, Yale University, West Haven, CT, USA
| | - Yuri Londer
- Microbial Sciences Institute, Yale University, West Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Fadel A Samatey
- Microbial Sciences Institute, Yale University, West Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | | | - Nikhil S Malvankar
- Microbial Sciences Institute, Yale University, West Haven, CT, USA.
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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21
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Wu L, Jin T, Chen H, Shen Z, Zhou Y. Conductive materials as fantastic toolkits to stimulate direct interspecies electron transfer in anaerobic digestion: new insights into methanogenesis contribution, characterization technology, and downstream treatment. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 326:116732. [PMID: 36402020 DOI: 10.1016/j.jenvman.2022.116732] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 10/29/2022] [Accepted: 11/05/2022] [Indexed: 06/16/2023]
Abstract
Direct interspecies electron transfer (DIET) stimulated by conductive materials (CMs) enables intercellular metabolic coupling that can address the unfavorable thermodynamical dilemma inherent in anaerobic digestion (AD). Although the DIET mechanism and stimulation have been extensively summarized, the methanogenesis contribution, characterization techniques, and downstream processes of CMs-led DIET in AD are surprisingly under-reviewed. Therefore, this review aimed to address these gaps. First, the contribution of CMs-led DIET to methanogenesis was re-evaluated by comparing the effect of various factors, including volatile fatty acids, free ammonia, and functional enzymes. It was revealed that AD systems are usually intricate and cannot allow the methanogenesis stimulation to be singularly attributed to the establishment of DIET. Additionally, considerable attention has been attached to the characterization of DIET occurrence, involving species identification, gene expression, electrical properties, cellular features, and syntrophic metabolism, suggesting the significance of accurate characterization methods for identifying the syntrophic metabolism interactions. Moreover, the type of CMs has a significant impact on AD downstream processes involving biogas purity, sludge dewaterability, and biosolids management. Finally, the central bottleneck consists in building a mathematical model of DIET to explain the mechanism of DIET in a deeper level from kinetics and thermodynamics.
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Affiliation(s)
- Linjun Wu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environment Sciences, Beijing 100012, PR China; Research Center of Environmental Pollution Control Engineering Technology, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China; School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Tao Jin
- China Construction Eco-environmental Group CO.,LTD, Beijing 100037, PR China
| | - Hong Chen
- Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha, 410114, China
| | - Zhiqiang Shen
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environment Sciences, Beijing 100012, PR China; Research Center of Environmental Pollution Control Engineering Technology, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China.
| | - Yuexi Zhou
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environment Sciences, Beijing 100012, PR China; Research Center of Environmental Pollution Control Engineering Technology, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China.
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22
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Wang F, Chan CH, Suciu V, Mustafa K, Ammend M, Si D, Hochbaum AI, Egelman EH, Bond DR. Structure of Geobacter OmcZ filaments suggests extracellular cytochrome polymers evolved independently multiple times. eLife 2022; 11:e81551. [PMID: 36062910 PMCID: PMC9473688 DOI: 10.7554/elife.81551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 09/03/2022] [Indexed: 11/26/2022] Open
Abstract
While early genetic and low-resolution structural observations suggested that extracellular conductive filaments on metal-reducing organisms such as Geobacter were composed of type IV pili, it has now been established that bacterial c-type cytochromes can polymerize to form extracellular filaments capable of long-range electron transport. Atomic structures exist for two such cytochrome filaments, formed from the hexaheme cytochrome OmcS and the tetraheme cytochrome OmcE. Due to the highly conserved heme packing within the central OmcS and OmcE cores, and shared pattern of heme coordination between subunits, it has been suggested that these polymers have a common origin. We have now used cryo-electron microscopy (cryo-EM) to determine the structure of a third extracellular filament, formed from the Geobacter sulfurreducens octaheme cytochrome, OmcZ. In contrast to the linear heme chains in OmcS and OmcE from the same organism, the packing of hemes, heme:heme angles, and between-subunit heme coordination is quite different in OmcZ. A branched heme arrangement within OmcZ leads to a highly surface exposed heme in every subunit, which may account for the formation of conductive biofilm networks, and explain the higher measured conductivity of OmcZ filaments. This new structural evidence suggests that conductive cytochrome polymers arose independently on more than one occasion from different ancestral multiheme proteins.
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Affiliation(s)
- Fengbin Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Chi Ho Chan
- Department of Plant and Microbial Biology, and BioTechnology Institute, University of MinnesotaSt. PaulUnited States
| | - Victor Suciu
- Division of Computing and Software Systems, University of Washington BothellBothellUnited States
| | - Khawla Mustafa
- Department of Chemistry, University of California, IrvineIrvineUnited States
| | - Madeline Ammend
- Department of Plant and Microbial Biology, and BioTechnology Institute, University of MinnesotaSt. PaulUnited States
| | - Dong Si
- Division of Computing and Software Systems, University of Washington BothellBothellUnited States
| | - Allon I Hochbaum
- Department of Chemistry, University of California, IrvineIrvineUnited States
- Department of Materials Science and Engineering, University of CaliforniaIrvineUnited States
- Department of Molecular Biology and Biochemistry, University of CaliforniaIrvineUnited States
- Department of Chemical and Biomolecular Engineering, University of CaliforniaIrvineUnited States
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Daniel R Bond
- Department of Plant and Microbial Biology, and BioTechnology Institute, University of MinnesotaSt. PaulUnited States
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23
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Li J, Chen D, Liu G, Li D, Tian Y, Feng Y. Construction of a new type of three-dimensional honeycomb-structure anode in microbial electrochemical systems for energy harvesting and pollutant removal. WATER RESEARCH 2022; 218:118429. [PMID: 35483206 DOI: 10.1016/j.watres.2022.118429] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 06/14/2023]
Abstract
Electrode materials occupy most of the construction cost of the microbial electrochemical system (MES), and the low mechanical strength and poor electrochemical performance of the commonly used traditional carbon-based materials restrict the promotion and application of this technology. In this study, polymer-based three-dimensional (3D) honeycomb-structure (HS) materials with good mechanical properties were used as supporting materials. Graphene (GR), carbon nanotube (CNT), and polypyrrole (PPy) was separately chosen as a surface conductivity coating layer for preparing MES anodes. The introduction of GR, CNT, and PPy on HS increased surface roughness, hydrophilicity, O and N content, electrochemically active surface area, and decreased charge transfer internal resistance, which promoted the adhesion of microorganisms on their surface and enhanced the extracellular electron transfer process at the electrode/microbe interface. The CNT-HS anode system got the better maximal power density (1700.7 ± 149.0 mW/m2) of the three modified anode systems and 3.60 times that of MES using CC (471.8 ± 27.2 mW/m2) as the anode. The accelerated reactions of the redox species in the outer cell membrane, the promoted electron shuttle secretion, and the enhanced abundance of the tricarboxylic acid cycle-related functional genes in biofilm led to better performance of the CNT-HS anode system. The CNT-HS anode system also exhibited long-term operational stability (>6 months) and a good chemical oxygen demand degradation effect. Furthermore, CNT-HS material exhibited its cost advantage, and its projected cost is estimated to be about $1.8/m2, much lower than the currently used MES anodes ($8.2-548.2/m2). Considering the good mechanical properties, simple preparation process, low manufacturing cost, long-term stability, excellent bio-electrochemical performance, and good pollutant removal ability, HS-based anode has promising potential for high-performance MES in applications.
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Affiliation(s)
- Jiannan Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Dahong Chen
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Guohong Liu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Da Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Yan Tian
- Harbin FengGe Ecological Environment Technology Co., Ltd., Harbin 150028, China
| | - Yujie Feng
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
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24
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Dong Y, Sui M, Jiang Y, Wu J, Wang X. Dibutyl phthalate weakens the role of electroactive biofilm as an efficient wastewater handler and related mechanism. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 807:151612. [PMID: 34780837 DOI: 10.1016/j.scitotenv.2021.151612] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/21/2021] [Accepted: 11/07/2021] [Indexed: 06/13/2023]
Abstract
Plasticizer plays an imperceptible role in interfering with the structure and function of wastewater biofilms, but the inherent influence mechanism still remains unknown. Here, the responses in electrochemical, structural, microbial properties of electroactive biofilm (EAB) to plasticizer (dibutyl phthalate, DBP) were comprehensively elucidated, especially for the property variation of extracellular polymeric substances (EPS). The biofilm-0 in DBP-absent environment contributed to 22.9% and 63.9% higher current, compared to those in 1 mg/L and 10 mg/L DBP environment (biofilm-1 and biofilm-10). Chronic exposure to high-concentration DBP significantly boosted the content and distribution width of polysaccharide in EPS, but the electron exchange capacity of EPS decreased 76.6% to 0.146 μmol e-/mg EPS for biofilm-10. The bacteria were subjected to metabolic function loss, in terms of esterase activity and membrane integrity, by using flow cytometry. The DBP exposure also imposed selective pressure on enrich EPS-secretion-related bacteria, while the Geobacter species decreased from 71.2% (biofilm-0) to 55.8% (biofilm-10). Consequently, the DBP exposure suppressed the pollutant degradation rate, which provided new insights into the EAB role as a promising core for wastewater treatment in plasticizer-existing environments.
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Affiliation(s)
- Yue Dong
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Mingrui Sui
- College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China
| | - Yiying Jiang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Jianyu Wu
- CAS Key Laboratory of Urban Pollutant Conversion, University of Science & Technology of China, Hefei 230026, China
| | - Xin Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria and Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
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25
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Yang J, Cheng S, Zhang S, Han W, Jin B. Modifying Ti 3C 2 MXene with NH 4+ as an excellent anode material for improving the performance of microbial fuel cells. CHEMOSPHERE 2022; 288:132502. [PMID: 34626659 DOI: 10.1016/j.chemosphere.2021.132502] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 06/13/2023]
Abstract
Poor anode performance is one of the main bottlenecks in the development of microbial fuel cells (MFCs) for practical applications. Multilayered Ti3C2 MXene (m-MXene) is an alternative anode modification material because of its high specific surface area and electrical conductivity. However, the multilayered structure, negatively charged surface, and electropositivity of m-MXene could limit its modification effects. In this work, we used a solution-phase flocculation method (ammonium ion method) to restack and aggregate MXene nanosheets as an anode modification material (n-MXene). The n-MXene-modified anode had a higher specific surface area, surface hydrophilicity and surface electropositivity than the m-MXene-modified anode. The n-MXene-modified anode obtained a maximum current density of 2.1 A m-2, which was 31.2% and 61.5% higher than that of the m-MXene-modified anode (1.6 A m-2) and bare carbon fiber cloth anode (1.3 A m-2). This improved anode performance was attributed to both the decrease in the charge transfer resistance and diffusion resistance, which were related to the increased quantity of biomass and microbial nanowire (or pili)-shaped filaments on the electrode surface. This work provides a simple and cost-effective approach to prepare MXene nanosheets for the modification of MFC anodes.
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Affiliation(s)
- Jiawei Yang
- State Key Laboratory of Clean Energy, Department of Energy Engineering, Zhejiang University, Hangzhou, 310027, PR China
| | - Shaoan Cheng
- State Key Laboratory of Clean Energy, Department of Energy Engineering, Zhejiang University, Hangzhou, 310027, PR China.
| | - Shenglong Zhang
- Department of Material Science and Engineering, Zhejiang University, Hangzhou, 310027, PR China
| | - Weiqiang Han
- Department of Material Science and Engineering, Zhejiang University, Hangzhou, 310027, PR China
| | - Beichen Jin
- State Key Laboratory of Clean Energy, Department of Energy Engineering, Zhejiang University, Hangzhou, 310027, PR China
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26
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Nano-Fe3C@2D-NC@CC as anode for improving extracellular electron transfer and electricity generation of microbial fuel cells. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2021.139618] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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27
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From iron to bacterial electroconductive filaments: Exploring cytochrome diversity using Geobacter bacteria. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2021.214284] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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28
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Chadwick GL, Skennerton CT, Laso-Pérez R, Leu AO, Speth DR, Yu H, Morgan-Lang C, Hatzenpichler R, Goudeau D, Malmstrom R, Brazelton WJ, Woyke T, Hallam SJ, Tyson GW, Wegener G, Boetius A, Orphan VJ. Comparative genomics reveals electron transfer and syntrophic mechanisms differentiating methanotrophic and methanogenic archaea. PLoS Biol 2022; 20:e3001508. [PMID: 34986141 PMCID: PMC9012536 DOI: 10.1371/journal.pbio.3001508] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 04/15/2022] [Accepted: 12/08/2021] [Indexed: 11/25/2022] Open
Abstract
The anaerobic oxidation of methane coupled to sulfate reduction is a microbially mediated process requiring a syntrophic partnership between anaerobic methanotrophic (ANME) archaea and sulfate-reducing bacteria (SRB). Based on genome taxonomy, ANME lineages are polyphyletic within the phylum Halobacterota, none of which have been isolated in pure culture. Here, we reconstruct 28 ANME genomes from environmental metagenomes and flow sorted syntrophic consortia. Together with a reanalysis of previously published datasets, these genomes enable a comparative analysis of all marine ANME clades. We review the genomic features that separate ANME from their methanogenic relatives and identify what differentiates ANME clades. Large multiheme cytochromes and bioenergetic complexes predicted to be involved in novel electron bifurcation reactions are well distributed and conserved in the ANME archaea, while significant variations in the anabolic C1 pathways exists between clades. Our analysis raises the possibility that methylotrophic methanogenesis may have evolved from a methanotrophic ancestor. A comparative genomics study of anaerobic methanotrophic (ANME) archaea reveals the genetic "parts list" associated with the repeated evolutionary transition between methanogenic and methanotrophic metabolism in the archaeal domain of life.
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Affiliation(s)
- Grayson L. Chadwick
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, United States of America
- * E-mail: (GLC); (VJO)
| | - Connor T. Skennerton
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, United States of America
| | - Rafael Laso-Pérez
- Max-Planck Institute for Marine Microbiology, Bremen, Germany
- MARUM, Center for Marine Environmental Science, and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Andy O. Leu
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Daan R. Speth
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, United States of America
| | - Hang Yu
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, United States of America
| | - Connor Morgan-Lang
- Graduate Program in Bioinformatics, University of British Columbia, Genome Sciences Centre, Vancouver, British Columbia, Canada
| | - Roland Hatzenpichler
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, United States of America
| | - Danielle Goudeau
- US Department of Energy Joint Genome Institute, Berkeley, California, United States of America
| | - Rex Malmstrom
- US Department of Energy Joint Genome Institute, Berkeley, California, United States of America
| | - William J. Brazelton
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, United States of America
| | - Tanja Woyke
- US Department of Energy Joint Genome Institute, Berkeley, California, United States of America
| | - Steven J. Hallam
- Graduate Program in Bioinformatics, University of British Columbia, Genome Sciences Centre, Vancouver, British Columbia, Canada
- Department of Microbiology & Immunology, University of British Columbia, British Columbia, Canada
- Genome Science and Technology Program, University of British Columbia, Vancouver, British Columbia, Canada
- ECOSCOPE Training Program, University of British Columbia, Vancouver, British Columbia, Canada
- Life Sciences Institute, University of British Columbia, British Columbia, Canada
| | - Gene W. Tyson
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Gunter Wegener
- Max-Planck Institute for Marine Microbiology, Bremen, Germany
- MARUM, Center for Marine Environmental Science, and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Antje Boetius
- Max-Planck Institute for Marine Microbiology, Bremen, Germany
- MARUM, Center for Marine Environmental Science, and Department of Geosciences, University of Bremen, Bremen, Germany
- Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
| | - Victoria J. Orphan
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, United States of America
- * E-mail: (GLC); (VJO)
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29
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Guo K, Cheng C, Chen L, Xie J, Li S, He S, Xiao F. Uranium enrichment performence and uranium stress mechanism of Deinococcus radiodurans. J Radioanal Nucl Chem 2021. [DOI: 10.1007/s10967-021-08018-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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30
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Casar CP, Momper LM, Kruger BR, Osburn MR. Iron-Fueled Life in the Continental Subsurface: Deep Mine Microbial Observatory, South Dakota, USA. Appl Environ Microbiol 2021; 87:e0083221. [PMID: 34378953 PMCID: PMC8478452 DOI: 10.1128/aem.00832-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/29/2021] [Indexed: 11/20/2022] Open
Abstract
Iron-bearing minerals are key components of the Earth's crust and potentially critical energy sources for subsurface microbial life. The Deep Mine Microbial Observatory (DeMMO) is situated in a range of iron-rich lithologies, and fracture fluids here reach concentrations as high as 8.84 mg/liter. Iron cycling is likely an important process, given the high concentrations of iron in fracture fluids and detection of putative iron-cycling taxa via marker gene surveys. However, a previous metagenomic survey detected no iron cycling potential at two DeMMO localities. Here, we revisited the potential for iron cycling at DeMMO using a new metagenomic data set including all DeMMO sites and FeGenie, a new annotation pipeline that is optimized for the detection of iron cycling genes. We annotated functional genes from whole metagenomic assemblies and metagenome-assembled genomes and characterized putative iron cycling pathways and taxa in the context of local geochemical conditions and available metabolic energy estimated from thermodynamic models. We reannotated previous metagenomic data, revealing iron cycling potential that was previously missed. Across both metagenomic data sets, we found that not only is there genetic potential for iron cycling at DeMMO, but also, iron is likely an important source of energy across the system. In response to the dramatic differences we observed between annotation approaches, we recommend the use of optimized pipelines where the detection of iron cycling genes is a major goal. IMPORTANCE We investigated iron cycling potential among microbial communities inhabiting iron-rich fracture fluids to a depth of 1.5 km in the continental crust. A previous study found no iron cycling potential in the communities despite the iron-rich nature of the system. A new tool for detecting iron cycling genes was recently published, which we used on a new data set. We combined this with a number of other approaches to get a holistic view of metabolic strategies across the communities, revealing iron cycling to be an important process here. In addition, we used the tool on the data from the previous study, revealing previously missed iron cycling potential. Iron is common in continental crust; thus, our findings are likely not unique to our study site. Our new view of important metabolic strategies underscores the importance of choosing optimized tools for detecting the potential for metabolisms like iron cycling that may otherwise be missed.
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Affiliation(s)
- C. P. Casar
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois, USA
| | - L. M. Momper
- Earth and Environmental Sciences Practice, Exponent, Inc., Pasadena, California, USA
| | - B. R. Kruger
- Division of Hydrologic Sciences, Desert Research Institute, Las Vegas, Nevada, USA
| | - M. R. Osburn
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois, USA
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31
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Garber AI, Cohen AB, Nealson KH, Ramírez GA, Barco RA, Enzingmüller-Bleyl TC, Gehringer MM, Merino N. Metagenomic Insights Into the Microbial Iron Cycle of Subseafloor Habitats. Front Microbiol 2021; 12:667944. [PMID: 34539592 PMCID: PMC8446621 DOI: 10.3389/fmicb.2021.667944] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 07/30/2021] [Indexed: 11/13/2022] Open
Abstract
Microbial iron cycling influences the flux of major nutrients in the environment (e.g., through the adsorptive capacity of iron oxides) and includes biotically induced iron oxidation and reduction processes. The ecological extent of microbial iron cycling is not well understood, even with increased sequencing efforts, in part due to limitations in gene annotation pipelines and limitations in experimental studies linking phenotype to genotype. This is particularly true for the marine subseafloor, which remains undersampled, but represents the largest contiguous habitat on Earth. To address this limitation, we used FeGenie, a database and bioinformatics tool that identifies microbial iron cycling genes and enables the development of testable hypotheses on the biogeochemical cycling of iron. Herein, we survey the microbial iron cycle in diverse subseafloor habitats, including sediment-buried crustal aquifers, as well as surficial and deep sediments. We inferred the genetic potential for iron redox cycling in 32 of the 46 metagenomes included in our analysis, demonstrating the prevalence of these activities across underexplored subseafloor ecosystems. We show that while some processes (e.g., iron uptake and storage, siderophore transport potential, and iron gene regulation) are near-universal, others (e.g., iron reduction/oxidation, siderophore synthesis, and magnetosome formation) are dependent on local redox and nutrient status. Additionally, we detected niche-specific differences in strategies used for dissimilatory iron reduction, suggesting that geochemical constraints likely play an important role in dictating the dominant mechanisms for iron cycling. Overall, our survey advances the known distribution, magnitude, and potential ecological impact of microbe-mediated iron cycling and utilization in sub-benthic ecosystems.
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Affiliation(s)
- Arkadiy I Garber
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Ashley B Cohen
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, United States
| | - Kenneth H Nealson
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Gustavo A Ramírez
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel.,College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA, United States
| | - Roman A Barco
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | | | - Michelle M Gehringer
- Department of Microbiology, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Nancy Merino
- Biosciences & Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
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Mukherjee P, Pichiah S, Packirisamy G, Jang M. Biocatalyst physiology and interplay: a protagonist of MFC operation. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:43217-43233. [PMID: 34165738 DOI: 10.1007/s11356-021-15015-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 06/16/2021] [Indexed: 06/13/2023]
Abstract
Microbial fuel cells (MFC) have been foreseen as a sustainable renewable energy resource to meet future energy demand. In the past, several studies have been executed in both benchtop and pilot scale to produce electrical energy from wastewater. The key role players in this technology that leads to the operation are microbes, mainly bacteria. The dominant among them is termed as "exoelectrogens" that have the capability to produce and transport electron by utilizing waste source. The current review focuses on such electrogenic bacteria's involvement for enhanced power generation of MFC. The pathway of electron transfer in their cell along and its conduction to the extracellular environment of the MFC system are critically discussed. The interaction of the microbes in various MFC operational conditions, including the role of substrate and solid electron acceptors, i.e., anode, external resistance, temperature, and pH, was also discussed in depth along with biotechnological advancement and future research perspective.
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Affiliation(s)
- Priya Mukherjee
- Environmental Nanotechnology Laboratory, Department of Environmental Science and Engineering, Indian Institute of Technology (ISM), Dhanbad, Jharkhand, 826004, India
| | - Saravanan Pichiah
- Environmental Nanotechnology Laboratory, Department of Environmental Science and Engineering, Indian Institute of Technology (ISM), Dhanbad, Jharkhand, 826004, India.
| | - Gopinath Packirisamy
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, 247667, India
| | - Min Jang
- Department of Environmental Engineering, Kwangwoon University, 447-1, Wolgye-dong Nowon-Gu, Seoul, South Korea
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Blake RC, Nautiyal A, Smith KA, Walton NN, Pendleton B, Wang Z. Ferrimicrobium acidiphilum Exchanges Electrons With a Platinum Electrode via a Cytochrome With Reduced Absorbance Maxima at 448 and 605 nm. Front Microbiol 2021; 12:705187. [PMID: 34381433 PMCID: PMC8350767 DOI: 10.3389/fmicb.2021.705187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 07/02/2021] [Indexed: 01/22/2023] Open
Abstract
Ferrimicrobium acidiphilum is a Gram-positive member of the Actinobacteria phylum that can respire aerobically or anaerobically with soluble Fe(II) or Fe(III), respectively, in sulfuric acid at pH 1.5. Cyclic voltammetry measurements using intact F. acidiphilum at pH 1.5 produced fully reversible voltammograms that were highly reproducible. The maximum current observed with the anodic peak was considerably less than was the maximum current observed with the cathodic peak. This difference was attributed to the competition between the platinum electrode and the soluble oxygen for the available electrons that were introduced by the cathodic wave into this facultative aerobic organism. The standard reduction potential of the intact organism was determined to be 786 mV vs. the standard hydrogen electrode, slightly more positive than that of 735 mV that was determined for soluble iron at pH 1.5 using the same apparatus. Chronocoulometry measurements conducted at different cell densities revealed that the intact organism remained in close proximity to the working electrode during the measurement, whereas soluble ionic iron did not. When the cyclic voltammetry of intact F. acidiphilum was monitored using an integrating cavity absorption meter, the only small changes in absorbance that were detected were consistent with the participation of a cellular cytochrome with reduced absorbance peaks at 448 and 605 nm. The cytochrome that participated in the exchange of electrons between the intact organism and extracellular solid electrodes like platinum was the same cytochrome whose oxidation was previously shown to be rate-limiting when the organism respired aerobically on extracellular soluble iron.
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Affiliation(s)
- Robert C Blake
- Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA, United States
| | - Amit Nautiyal
- Department of Chemistry, Xavier University of Louisiana, New Orleans, LA, United States
| | - Kayla A Smith
- Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA, United States
| | - Noelle N Walton
- Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA, United States
| | - Brealand Pendleton
- Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA, United States
| | - Zhe Wang
- Department of Chemistry, Oakland University, Rochester, NY, United States
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Proteolytic Maturation of the Outer Membrane c-Type Cytochrome OmcZ by a Subtilisin-Like Serine Protease Is Essential for Optimal Current Production by Geobacter sulfurreducens. Appl Environ Microbiol 2021; 87:e0261720. [PMID: 33837010 DOI: 10.1128/aem.02617-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
An outer membrane c-type cytochrome (OmcZ) in Geobacter sulfurreducens is essential for optimal current production in microbial fuel cells. OmcZ exists in two forms, small and large, designated OmcZS and OmcZL, respectively. However, it is still not known how these two structures are formed. A mutant with a disruption of the GSU2075 gene encoding a subtilisin-like serine protease (designated ozpA for the OmcZ protease), which is located downstream of omcZ, produced low currents at a level similar to that of the omcZ-deficient mutant strain. Biochemical analyses revealed that the ozpA mutant accumulated OmcZL and did not produce OmcZS, which is thought to be a mature form that is essential for the extracellular electron transfer to the electrode. A heterologous expression system cell lysate from an Escherichia coli strain producing OzpA cleaved OmcZL and generated OmcZS as the proteolytic product. Among the culture supernatant, loosely bound outer surface, and intracellular protein fractions from wild-type G. sulfurreducens, only the culture supernatant protein fraction showed OmcZL cleavage activity, indicating that the mature form of OmcZ, OmcZS, can be produced outside the cells. These results indicate that OzpA is an essential protease for current production via the maturation of OmcZ, and OmcZS is the key to the extracellular electron transfer to electrodes. This proteolytic maturation of OmcZ is a unique regulation among known c-type cytochromes in G. sulfurreducens. IMPORTANCE Microbial fuel cells are a promising technology for energy generation from various waste types. However, the molecular mechanisms of microbial extracellular electron transfer to the electrode need to be elucidated. G. sulfurreducens is a common key player in electricity generation in mixed-culture microbial fuel cell systems and a model microorganism for the study of extracellular electron transfer. Outer membrane c-type cytochrome OmcZ is essential for an optimal current production by G. sulfurreducens. OmcZ proteolytic cleavage occurs during maturation, but the underlying mechanism is unknown. This study identifies a subtilisin-like protease, OzpA, which plays a role in cleaving OmcZ and generating the mature form of OmcZ (OmcZS). OzpA is essential for current production and, thus, the proteolytic maturation of OmcZ. This is a novel regulation of the c-type cytochrome for G. sulfurreducens extracellular electron transfer. This study also provides new insights into the design strategy and development of microbial extracellular electron transfer for an efficient energy conversion from chemical energy to electricity.
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Abstract
Extracellular electron transfer (EET) is an important biological process in microbial physiology as found in dissimilatory metal oxidation/reduction and interspecies electron transfer in syntrophy in natural environments. EET also plays a critical role in microorganisms relevant to environmental biotechnology in metal-contaminated areas, metal corrosion, bioelectrochemical systems, and anaerobic digesters. Geobacter species exist in a diversity of natural and artificial environments. One of the outstanding features of Geobacter species is the capability of direct EET with solid electron donors and acceptors, including metals, electrodes, and other cells. Therefore, Geobacter species are pivotal in environmental biogeochemical cycles and biotechnology applications. Geobacter sulfurreducens, a representative Geobacter species, has been studied for direct EET as a model microorganism. G. sulfurreducens employs electrically conductive pili (e-pili) and c-type cytochromes for the direct EET. The biological function and electronics applications of the e-pili have been reviewed recently, and this review focuses on the cytochromes. Geobacter species have an unusually large number of cytochromes encoded in their genomes. Unlike most other microorganisms, Geobacter species localize multiple cytochromes in each subcellular fraction, outer membrane, periplasm, and inner membrane, as well as in the extracellular space, and differentially utilize these cytochromes for EET with various electron donors and acceptors. Some of the cytochromes are functionally redundant. Thus, the EET in Geobacter is complicated. Geobacter coordinates the cytochromes with other cellular components in the elaborate EET system to flourish in the environment.
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Affiliation(s)
- Toshiyuki Ueki
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
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Sheik CS, Badalamenti JP, Telling J, Hsu D, Alexander SC, Bond DR, Gralnick JA, Lollar BS, Toner BM. Novel Microbial Groups Drive Productivity in an Archean Iron Formation. Front Microbiol 2021; 12:627595. [PMID: 33859627 PMCID: PMC8042283 DOI: 10.3389/fmicb.2021.627595] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 03/01/2021] [Indexed: 12/23/2022] Open
Abstract
Deep subsurface environments are decoupled from Earth's surface processes yet diverse, active, and abundant microbial communities thrive in these isolated environments. Microbes inhabiting the deep biosphere face unique challenges such as electron donor/acceptor limitations, pore space/fracture network limitations, and isolation from other microbes within the formation. Of the few systems that have been characterized, it is apparent that nutrient limitations likely facilitate diverse microbe-microbe interactions (i.e., syntrophic, symbiotic, or parasitic) and that these interactions drive biogeochemical cycling of major elements. Here we describe microbial communities living in low temperature, chemically reduced brines at the Soudan Underground Mine State Park, United States. The Soudan Iron mine intersects a massive hematite formation at the southern extent of the Canadian Shield. Fractured rock aquifer brines continuously flow from exploratory boreholes drilled circa 1960 and are enriched in deuterium compared to the global meteoric values, indicating brines have had little contact with surface derived waters, and continually degas low molecular weight hydrocarbons C1-C4. Microbial enrichments suggest that once brines exit the boreholes, oxidation of the hydrocarbons occur. Amplicon sequencing show these borehole communities are low in diversity and dominated by Firmicute and Proteobacteria phyla. From the metagenome assemblies, we recovered approximately thirty genomes with estimated completion over 50%. Analysis of genome taxonomy generally followed the amplicon data, and highlights that several of the genomes represent novel families and genera. Metabolic reconstruction shows two carbon-fixation pathways were dominant, the Wood-Ljungdahl (acetogenesis) and Calvin-Benson-Bassham (via RuBisCo), indicating that inorganic carbon likely enters into the microbial foodweb with differing carbon fractionation potentials. Interestingly, methanogenesis is likely driven by Methanolobus and suggests cycling of methylated compounds and not H2/CO2 or acetate. Furthermore, the abundance of sulfate in brines suggests cryptic sulfur cycling may occur, as we detect possible sulfate reducing and thiosulfate oxidizing microorganisms. Finally, a majority of the microorganisms identified contain genes that would allow them to participate in several element cycles, highlighting that in these deep isolated systems metabolic flexibility may be an important life history trait.
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Affiliation(s)
- Cody S. Sheik
- Department of Biology and the Large Lakes Observatory, University of Minnesota Duluth, Duluth, MN, United States
| | - Jonathan P. Badalamenti
- University of Minnesota Genomics Center, University of Minnesota Twin Cities, Minneapolis, MN, United States
- Biotechnology Institute, University of Minnesota Twin Cities, Saint Paul, MN, United States
| | - Jon Telling
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David Hsu
- Biotechnology Institute, University of Minnesota Twin Cities, Saint Paul, MN, United States
- Plant and Microbial Biology, University of Minnesota Twin Cities, Saint Paul, MN, United States
| | - Scott C. Alexander
- Department of Earth and Environmental Sciences, University of Minnesota Twin Cities, Minneapolis, MN, United States
| | - Daniel R. Bond
- Biotechnology Institute, University of Minnesota Twin Cities, Saint Paul, MN, United States
- Plant and Microbial Biology, University of Minnesota Twin Cities, Saint Paul, MN, United States
| | - Jeffrey A. Gralnick
- Biotechnology Institute, University of Minnesota Twin Cities, Saint Paul, MN, United States
- Plant and Microbial Biology, University of Minnesota Twin Cities, Saint Paul, MN, United States
| | | | - Brandy M. Toner
- Department of Earth and Environmental Sciences, University of Minnesota Twin Cities, Minneapolis, MN, United States
- Department of Soil, Water, and Climate, University of Minnesota Twin Cities, Saint Paul, MN, United States
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He X, Chadwick G, Jiménez Otero F, Orphan V, Meile C. Spatially Resolved Electron Transport through Anode‐Respiring
Geobacter sulfurreducens
Biofilms: Controls and Constraints. ChemElectroChem 2021. [DOI: 10.1002/celc.202100111] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Xiaojia He
- Department of Marine Sciences University of Georgia Athens GA USA
| | - Grayson Chadwick
- Division of Geological and Planetary Sciences California Institute of Technology Pasadena CA USA
| | | | - Victoria Orphan
- Division of Geological and Planetary Sciences California Institute of Technology Pasadena CA USA
| | - Christof Meile
- Department of Marine Sciences University of Georgia Athens GA USA
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Dissecting the Structural and Conductive Functions of Nanowires in Geobacter sulfurreducens Electroactive Biofilms. mBio 2021; 13:e0382221. [PMID: 35164556 PMCID: PMC8844916 DOI: 10.1128/mbio.03822-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Conductive nanowires are thought to contribute to long-range electron transfer (LET) in Geobacter sulfurreducens anode biofilms. Three types of nanowires have been identified: pili, OmcS, and OmcZ. Previous studies highlighted their conductive function in anode biofilms, yet a structural function also has to be considered. We present here a comprehensive analysis of the function of nanowires in LET by inhibiting the expression of each nanowire. Meanwhile, flagella with poor conductivity were expressed to recover the structural function but not the conductive function of nanowires in the corresponding nanowire mutant strain. The results demonstrated that pili played a structural but not a conductive function in supporting biofilm formation. In contrast, the OmcS nanowire played a conductive but not a structural function in facilitating electron transfer in the biofilm. The OmcZ nanowire played both a structural and a conductive function to contribute to current generation. Expression of the poorly conductive flagellum was shown to enhance biofilm formation, subsequently increasing current generation. These data support a model in which multiheme cytochromes facilitate long-distance electron transfer in G. sulfurreducens biofilms. Our findings also suggest that the formation of a thicker biofilm, which contributed to a higher current generation by G. sulfurreducens, was confined by the biofilm formation deficiency, and this has applications in microbial electrochemical systems. IMPORTANCE The low power generation of microbial fuel cells limits their utility. Many factors can affect power generation, including inefficient electron transfer in the anode biofilm. Thus, understanding the mechanism(s) of electron transfer provides a pathway for increasing the power density of microbial fuel cells. Geobacter sulfurreducens was shown to form a thick biofilm on the anode. Cells far away from the anode reduce the anode through long-range electron transfer. Based on their conductive properties, three types of nanowires have been hypothesized to directly facilitate long-range electron transfer: pili, OmcS, and OmcZ nanowires. However, their structural contributions to electron transfer in anode biofilm have not been elucidated. Based on studies of mutants lacking one or more of these facilitators, our results support a cytochrome-mediated electron transfer process in Geobacter biofilms and highlight the structural contribution of nanowires in anode biofilm formation, which contributes to biofilm formation and current generation, thereby providing a strategy to increase current generation.
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Lu Y, Xie Q, Tang L, Yu J, Wang J, Yang Z, Fan C, Zhang S. The reduction of nitrobenzene by extracellular electron transfer facilitated by Fe-bearing biochar derived from sewage sludge. JOURNAL OF HAZARDOUS MATERIALS 2021; 403:123682. [PMID: 33264880 DOI: 10.1016/j.jhazmat.2020.123682] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/04/2020] [Accepted: 08/06/2020] [Indexed: 06/12/2023]
Abstract
In this work, the incorporation of Fe-bearing sludge-derived biochar greatly enhanced both biotic and abiotic reduction of nitrobenzene (NB) to aniline, which was attributed to the concomitant microbial dissimilatory iron reduction. Biogenic Fe(II) produced by Geobacter sulfurreducens dominated the anaerobic reduction of NB following the pseudo-first-order kinetic. Besides, the increase of pyrolysis temperature from 600 to 900 ℃ to generate biochar resulted in an accelerated removal rate of NB in Geobacter-biochar combined system. The morphology and structural characterization of biochar with G. sulfurreducens confirmed the formation of conductive bacteria-biochar aggregates. Electrochemical measurements suggested the presence of graphitized domains and quinone-like moieties in biochar as redox-active centers, which might play an important role in accelerating electron transfer for microbial dissimilatory iron reduction and NB degradation. This study provides a feasible way of using Fe-bearing sludge as a valuable feedstock for biochar generation and its application with electrochemically active bacteria for the bioremediation of nitroaromatic compounds-polluted wastewater.
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Affiliation(s)
- Yue Lu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China.
| | - Qingqing Xie
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
| | - Lin Tang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China.
| | - Jiangfang Yu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
| | - Jingjing Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
| | - Zhaohui Yang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
| | - Changzheng Fan
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
| | - Shoujuan Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
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Igarashi K, Kato S. Reductive Transformation of Fe(III) (oxyhydr)Oxides by Mesophilic Homoacetogens in the Genus Sporomusa. Front Microbiol 2021; 12:600808. [PMID: 33633701 PMCID: PMC7901989 DOI: 10.3389/fmicb.2021.600808] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/04/2021] [Indexed: 01/10/2023] Open
Abstract
Microbial reduction of iron contributes to the dissolution and transformation of iron-containing minerals in nature. Diverse groups of homoacetogenic bacteria (homoacetogens) have been reported to reduce insoluble Fe(III) oxides, such as hydrous ferric oxide (HFO), an Fe(III) mineral commonly found in soils and sediments. Several members of genus Sporomusa reportedly oxidize Fe(0), indicating the presence of an extracellular electron-uptake mechanism. However, the ability of the genus to reduce insoluble Fe(III) oxides is limited, and the underlying reduction mechanism remains to be elucidated. In this study, the HFO reduction ability of three Sporomusa spp. (Sporomusa sp. strain GT1, Sporomusa sphaeroides, and Sporomusa ovata) and a homoacetogen of a different genus (Acetobacterium woodii) were assayed under organotrophic (ethanol) and lithotrophic (H2 + CO2) conditions without a chelator or reducing reagent. All tested homoacetogens showed acetogenic growth and concomitant reduction of HFO under both organotrophic and lithotrophic conditions. Analysis of the growth stoichiometry showed that Fe(III) reduction does not support direct energy conservation, thereby indicating that Fe(III) reduction is a side reaction of acetogenesis to dissipate the excess reducing power. HFO was reduced to a soluble Fe(II) form by microbial activity. In addition, we observed that strain GT1, S. sphaeroides, and S. ovata reduced crystalline Fe(III) oxides, and HFO was reductively transformed into magnetite (Fe3O4) under phosphate-limiting conditions. Separation of HFO by a dialysis membrane still permitted Fe(II) production, although the reduction rate was decreased, suggesting that Fe(III) reduction is at least partially mediated by soluble redox compound(s) secreted from the cells. Finally, culture experiments and comparative genomic analysis suggested that electron transfer by flavins and multiheme c-type cytochrome were not directly correlated with Fe(III) reduction activity. This study reveals the capability of Sporomusa spp. in the reductive transformation of iron mineral and indicates the potential involvement of these organisms in iron and other mineral cycles in nature.
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Affiliation(s)
- Kensuke Igarashi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan
| | - Souichiro Kato
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan.,Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
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Kang HJ, Lee SH, Lim TG, Park JH, Kim B, Buffière P, Park HD. Recent advances in methanogenesis through direct interspecies electron transfer via conductive materials: A molecular microbiological perspective. BIORESOURCE TECHNOLOGY 2021; 322:124587. [PMID: 33358582 DOI: 10.1016/j.biortech.2020.124587] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 05/28/2023]
Abstract
Conductive materials can serve as biocatalysts during direct interspecies electron transfer for methanogenesis in anaerobic reactors. However, the mechanism promoting direct interspecies electron transfer in anaerobic reactors, particularly under environments in which diverse substrates and microorganisms coexist, remains to be elucidated from a scientific or an engineering point of view. Currently, many molecular microbiological approaches are employed to understand the fundamentals of this phenomenon. Here, the direct interspecies electron transfer mechanisms and relevant microorganisms identified to date using molecular microbiological methods were critically reviewed. Moreover, molecular microbiological methods for direct interspecies electron transfer used in previous studies and important findings thus revealed were analyzed. This review will help us better understand the phenomena of direct interspecies electron transfer using conductive materials and offer a framework for future molecular microbiological studies.
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Affiliation(s)
- Hyun-Jin Kang
- School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, South Korea
| | - Sang-Hoon Lee
- School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, South Korea
| | - Tae-Guen Lim
- School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, South Korea
| | - Jeong-Hoon Park
- Sustainable Technology and Wellness R&D Group, Korea Institute of Industrial Technology (KITECH), Jeju-si, South Korea
| | - Boram Kim
- DEEP Laboratory, Université de Lyon, INSA Lyon, Lyon, France
| | - Pierre Buffière
- DEEP Laboratory, Université de Lyon, INSA Lyon, Lyon, France
| | - Hee-Deung Park
- School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, South Korea.
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Faustino MM, Fonseca BM, Costa NL, Lousa D, Louro RO, Paquete CM. Crossing the Wall: Characterization of the Multiheme Cytochromes Involved in the Extracellular Electron Transfer Pathway of Thermincola ferriacetica. Microorganisms 2021; 9:microorganisms9020293. [PMID: 33572691 PMCID: PMC7911101 DOI: 10.3390/microorganisms9020293] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 12/13/2022] Open
Abstract
Bioelectrochemical systems (BES) are emerging as a suite of versatile sustainable technologies to produce electricity and added-value compounds from renewable and carbon-neutral sources using electroactive organisms. The incomplete knowledge on the molecular processes that allow electroactive organisms to exchange electrons with electrodes has prevented their real-world implementation. In this manuscript we investigate the extracellular electron transfer processes performed by the thermophilic Gram-positive bacteria belonging to the Thermincola genus, which were found to produce higher levels of current and tolerate higher temperatures in BES than mesophilic Gram-negative bacteria. In our study, three multiheme c-type cytochromes, Tfer_0070, Tfer_0075, and Tfer_1887, proposed to be involved in the extracellular electron transfer pathway of T. ferriacetica, were cloned and over-expressed in E. coli. Tfer_0070 (ImdcA) and Tfer_1887 (PdcA) were purified and biochemically characterized. The electrochemical characterization of these proteins supports a pathway of extracellular electron transfer via these two proteins. By contrast, Tfer_0075 (CwcA) could not be stabilized in solution, in agreement with its proposed insertion in the peptidoglycan wall. However, based on the homology with the outer-membrane cytochrome OmcS, a structural model for CwcA was developed, providing a molecular perspective into the mechanisms of electron transfer across the peptidoglycan layer in Thermincola.
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Lovley DR, Yao J. Intrinsically Conductive Microbial Nanowires for 'Green' Electronics with Novel Functions. Trends Biotechnol 2021; 39:940-952. [PMID: 33419586 DOI: 10.1016/j.tibtech.2020.12.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 10/22/2022]
Abstract
Intrinsically conductive protein nanowires, microbially produced from inexpensive, renewable feedstocks, are a sustainable alternative to traditional nanowire electronic materials, which require high energy inputs and hazardous conditions/chemicals for fabrication and can be highly toxic. Pilin-based nanowires can be tailored for specific functions via the design of synthetic pilin genes to tune wire conductivity or introduce novel functionalities. Other microbially produced nanowire options for electronics may include cytochrome wires, curli fibers, and the conductive fibers of cable bacteria. Proof-of-concept protein nanowire electronics that have been successfully demonstrated include biomedical sensors, neuromorphic devices, and a device that generates electricity from ambient humidity. Further development of applications will require interdisciplinary teams of engineers, biophysicists, and synthetic biologists.
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Affiliation(s)
- 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, USA; Institute for Applied Life Sciences (IALS), University of Massachusetts, Amherst, MA, USA.
| | - Jun Yao
- Institute for Applied Life Sciences (IALS), University of Massachusetts, Amherst, MA, USA; Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, MA, USA; Department of Biomedical Engineering, University of Massachusetts, Amherst, MA, USA
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Sui M, Li Y, Jiang Y, Zhang Y, Wang L, Zhang W, Wang X. Light exposure interferes with electroactive biofilm enrichment and reduces extracellular electron transfer efficiency. WATER RESEARCH 2021; 188:116512. [PMID: 33161361 DOI: 10.1016/j.watres.2020.116512] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/18/2020] [Accepted: 10/10/2020] [Indexed: 06/11/2023]
Abstract
Light plays a vital role in shaping the structure of natural biofilms, but the effect of light on electroactive biofilm (EAB) has not been systematically studied. Herein, the influence of light on the formation of EAB was investigated. The EAB grown in darkness was more electroactive (EAB-0) with a peak current of ∼4.5 A/m2, which was 196 and 5556 times higher than EABs formed under light intensities of 600 (EAB-600) and 1200 lux (EAB-1200). A thin EAB (30 μm) with spherical pink aggregates was obtained after 13 days in the darkness, comparing to a dense and flat biofilm grown under light conditions. Although the biomass in EAB-1200 (38.5 ± 1.6 mg/L) was 3 times larger than that in EAB-0 (11.4 ± 1.8 mg/L), the degradation of substrate was not sufficient. EAB-0 contained 85% Geobacter species, while the Rhodopseudomonas species made up 66% and 75% of EAB-600 and EAB-1200, respectively. The polysaccharides produced by EAB-1200 was 4801 ± 253 mg/m2, which were 2.3 times higher than 2073 ± 160 mg/m2 of EAB-0, resulting in lower electro-conductivity of the extracellular polymeric substances (EPS) under light conditions. Our findings confirmed that the light exposure affected EAB performance by altering the microbial components, electron transfer capacity, and biofilm morphology, which can be used in predictions of the formation and properties of engineered EAB in outdoor environments.
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Affiliation(s)
- Mingrui Sui
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Yi Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
| | - Yiying Jiang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Yuhang Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Longfei Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Wenlong Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Xin Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria and Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
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Chen H, Simoska O, Lim K, Grattieri M, Yuan M, Dong F, Lee YS, Beaver K, Weliwatte S, Gaffney EM, Minteer SD. Fundamentals, Applications, and Future Directions of Bioelectrocatalysis. Chem Rev 2020; 120:12903-12993. [DOI: 10.1021/acs.chemrev.0c00472] [Citation(s) in RCA: 118] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Hui Chen
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Olja Simoska
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Koun Lim
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Matteo Grattieri
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Mengwei Yuan
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Fangyuan Dong
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Yoo Seok Lee
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Kevin Beaver
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Samali Weliwatte
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Erin M. Gaffney
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Shelley D. Minteer
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
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Zhang B, Cheng HY, Wang A. Extracellular electron transfer through visible light induced excited-state outer membrane C-type cytochromes of Geobacter sulfurreducens. Bioelectrochemistry 2020; 138:107683. [PMID: 33421898 DOI: 10.1016/j.bioelechem.2020.107683] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 09/09/2020] [Accepted: 09/24/2020] [Indexed: 11/26/2022]
Abstract
Dissimilatory metal-reducing bacteria (DMRB) have a variety of c-type cytochromes (OM c-cyts) intercalated in their outer membrane, and this structure serves as the physiological basis for DMRB to carry out the extracellular electron transfer processes. Using Geobacter sulfurreducens as a model DMRB, we demonstrated that visible-light illumination could alter the electronic state of OM c-cyts from the ground state to the excited state in vivo. The existence of excited-state OM c-cyts in vivo was confirmed by spectroscopy. More importantly, excited-state OM c-cyts had a more negative potential compared to their ground-state counterparts, conferring DMRB with an extra pathway to transfer electrons to semi-conductive electron acceptors. To demonstrate this, using a TiO2-coated electrode as an electron acceptor, we showed that G. sulfurreducens could directly utilise the conduction band of TiO2 as an electron acceptor under visible-light illumination (λ > 420 nm) without causing TiO2 charge separation. When G. sulfurreducens was subject to visible-light illumination, the rate of extracellular electron transfer (EET) to TiO2 accelerated by over 8-fold compared to that observed under dark conditions. Results of additional electrochemical tests provided complementary evidence to support that G. sulfurreducens utilised excited-state OM c-cyts to enhance EET to TiO2.
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Affiliation(s)
- Bo Zhang
- CAS Key Lab of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Hao-Yi Cheng
- CAS Key Lab of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Aijie Wang
- CAS Key Lab of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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A New Approach for Evaluating Electron Transfer Dynamics by Using In Situ Resonance Raman Microscopy and Chronoamperometry in Conjunction with a Dynamic Model. Appl Environ Microbiol 2020; 86:AEM.01535-20. [PMID: 32826217 PMCID: PMC7531965 DOI: 10.1128/aem.01535-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 08/09/2020] [Indexed: 01/30/2023] Open
Abstract
Bioelectrochemical systems can fill a vast array of application niches, due to the control of redox reactions that it offers. Although native microorganisms are preferred for applications such as bioremediation, more control is required for applications such as biosensors or biocomputing. The development of a chassis organism, in which the EET is well defined and readily controllable, is therefore essential. The combined approach in this work offers a unique way of monitoring and describing the reaction kinetics of a G. sulfurreducens biofilm, as well as offering a dynamic model that can be used in conjunction with applications such as biosensors. Geobacter sulfurreducens is a good candidate as a chassis organism due to its ability to form thick, conductive biofilms, enabling long-distance extracellular electron transfer (EET). Due to the complexity of EET pathways in G. sulfurreducens, a dynamic approach is required to study genetically modified EET rates in the biofilm. By coupling online resonance Raman microscopy with chronoamperometry, we were able to observe the dynamic discharge response in the biofilm’s cytochromes to an increase in anode voltage. Measuring the heme redox state alongside the current allows for the fitting of a dynamic model using the current response and a subsequent validation of the model via the value of a reduced cytochrome c Raman peak. The modeled reduced cytochromes closely fitted the Raman response data from the G. sulfurreducens wild-type strain, showing the oxidation of heme groups in cytochromes until a new steady state was achieved. Furthermore, the use of a dynamic model also allows for the calculation of internal rates, such as acetate and NADH consumption rates. The Raman response of a mutant lacking OmcS showed a higher initial oxidation rate than predicted, followed by an almost linear decrease of the reduced mediators. The increased initial rate could be attributed to an increase in biofilm conductivity, previously observed in biofilms lacking OmcS. One explanation for this is that OmcS acts as a conduit between cytochromes; therefore, deleting the gene restricts the rate of electron transfer to the extracellular matrix. This could, however, be modeled assuming a linear oxidation rate of intercellular mediators. IMPORTANCE Bioelectrochemical systems can fill a vast array of application niches, due to the control of redox reactions that it offers. Although native microorganisms are preferred for applications such as bioremediation, more control is required for applications such as biosensors or biocomputing. The development of a chassis organism, in which the EET is well defined and readily controllable, is therefore essential. The combined approach in this work offers a unique way of monitoring and describing the reaction kinetics of a G. sulfurreducens biofilm, as well as offering a dynamic model that can be used in conjunction with applications such as biosensors.
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Zakaria BS, Dhar BR. Changes in syntrophic microbial communities, EPS matrix, and gene-expression patterns in biofilm anode in response to silver nanoparticles exposure. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 734:139395. [PMID: 32454336 DOI: 10.1016/j.scitotenv.2020.139395] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/10/2020] [Accepted: 05/10/2020] [Indexed: 05/25/2023]
Abstract
Understanding the toxic effect of silver nanoparticles (AgNPs) on various biological wastewater treatment systems is of significant interest to researchers. In recent years, microbial electrochemical technologies have opened up new opportunities for bioenergy and chemicals production from organic wastewater. However, the effects of AgNPs on microbial electrochemical systems are yet to be understood fully. Notably, no studies have investigated the impact of AgNPs on a microbial electrochemical system fed with a complex fermentable substrate. Here, we investigated the impact of AgNPs (50 mg/L) exposure to a biofilm anode in a microbial electrolysis cell (MEC) fed with glucose. The volumetric current density was 29 ± 2.0 A/m3 before the AgNPs exposure, which decreased to 20 ± 2.2 A/m3 after AgNPs exposure. The biofilms produced more extracellular polymeric substances (EPS) to cope with the AgNPs exposure, while carbohydrate to protein ratio in EPS considerably increased from 0.4 to 0.7. Scanning electron microscope (SEM) imaging also confirmed the marked excretion of EPS, forming a thick layer covering the anode biofilms after AgNPs injection. Transmission electron microscope (TEM) imaging showed that AgNPs still penetrated some microbial cells, which could explain the deterioration of MEC performance after AgNPs exposure. The relative expression level of the quorum signalling gene (LuxR) increased by 30%. Microbial community analyses suggested that various fermentative bacterial species (e.g., Bacteroides, Synergistaceae_vadinCA02, Dysgonomonas, etc.) were susceptible to AgNPs toxicity, which led to the disruption of their syntrophic partnership with electroactive bacteria. The abundance of some specific electroactive bacteria (e.g., Geobacter species) also decreased. Moreover, decreased relative expressions of various extracellular electron transfer associated genes (omcB, omcC, omcE, omcZ, omcS, and pilA) were observed. However, the members of family Enterobacteriaceae, known to perform a dual function of fermentation and anodic respiration, became dominant after biofilm anode exposed to AgNPs. Thus, EPS extraction provided partial protection against AgNPs exposure.
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Affiliation(s)
- Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AB T6G 1H9, Canada.
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Electric field stimulates production of highly conductive microbial OmcZ nanowires. Nat Chem Biol 2020; 16:1136-1142. [PMID: 32807967 PMCID: PMC7502555 DOI: 10.1038/s41589-020-0623-9] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 07/09/2020] [Indexed: 12/26/2022]
Abstract
Multifunctional living materials are attractive due to their powerful ability to self-repair and replicate. However, most natural materials lack electronic functionality. Here we show that an electric field, applied to electricity-producing Geobacter sulfurreducens biofilms, stimulates production of previously unknown cytochrome OmcZ nanowires with 1,000-fold higher conductivity (30 S/cm), and 3-fold higher stiffness (1.5 GPa), than the cytochrome OmcS nanowires that are important in natural environments. Using chemical imaging-based multimodal nanospectroscopy, we correlate protein structure with function, and observe pH-induced conformational switching to β-sheets in individual nanowires, which increases their stiffness and conductivity by 100-fold due to enhanced π-stacking of heme groups; this was further confirmed by computational modelling and bulk spectroscopic studies. These nanowires can transduce mechanical and chemical stimuli into electrical signals to perform sensing, synthesis and energy production. These findings of biologically-produced, highly-conductive protein nanowires may help to guide the development of seamless, bidirectional interfaces between biological and electronic systems.
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50
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Electrogenic Biofilm Development Determines Charge Accumulation and Resistance to pH Perturbation. ENERGIES 2020. [DOI: 10.3390/en13143521] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The electrogenic biofilm and the bio-electrode interface are the key biocatalytic components in bioelectrochemical systems (BES) and can have a large impact on cell performance. This study used four different anodic carbons to investigate electrogenic biofilm development to determine the influence of charge accumulation and biofilm growth on system performance and how biofilm structure may mitigate against pH perturbations. Power production was highest (1.40 W/m3) using carbon felt, but significant power was also produced when felt carbon was open-circuit acclimated in a control reactor (0.95 W/m3). The influence of carbon material on electrogenic biofilm development was determined by measuring the level of biofilm growth, using sequencing to identify the microbial populations and confocal microscopy to understand the spatial locations of key microbial groups. Geobacter spp. were found to be enriched in closed-circuit operation and these were in close association with the carbon anode, but these were not observed in the open-circuit controls. Electrochemical analysis also demonstrated that the highest mid-point anode potentials were close to values reported for cytochromes from Geobacter sulfurreductans. Biofilm development was greatest in felt anodes (closed-circuit acclimated 1209 ng/μL DNA), and this facilitated the highest pseudo-capacitive values due to the presence of redox-active species, and this was associated with higher levels of power production and also served to mitigate against the effects of low-pH operation. Supporting carbon anode structures are key to electrogenic biofilm development and associated system performance and are also capable of protecting electrochemically active bacteria from the effects of environmental perturbations.
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