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Khan SS, Kour D, Kaur T, Sharma A, Kumar S, Kumari S, Ramniwas S, Singh S, Negi R, Sharma B, Devi T, Kumari C, Kour H, Kaur M, Rai AK, Singh S, Rasool S, Yadav AN. Microbial Nanotechnology for Precision Nanobiosynthesis: Innovations, Current Opportunities and Future Perspectives for Industrial Sustainability. Curr Microbiol 2024; 81:251. [PMID: 38954017 DOI: 10.1007/s00284-024-03772-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 06/14/2024] [Indexed: 07/04/2024]
Abstract
A new area of biotechnology is nanotechnology. Nanotechnology is an emerging field that aims to develope various substances with nano-dimensions that have utilization in the various sectors of pharmaceuticals, bio prospecting, human activities and biomedical applications. An essential stage in the development of nanotechnology is the creation of nanoparticles. To increase their biological uses, eco-friendly material synthesis processes are becoming increasingly important. Recent years have shown a lot of interest in nanostructured materials due to their beneficial and unique characteristics compared to their polycrystalline counterparts. The fascinating performance of nanomaterials in electronics, optics, and photonics has generated a lot of interest. An eco-friendly approach of creating nanoparticles has emerged in order to get around the drawbacks of conventional techniques. Today, a wide range of nanoparticles have been created by employing various microbes, and their potential in numerous cutting-edge technological fields have been investigated. These particles have well-defined chemical compositions, sizes, and morphologies. The green production of nanoparticles mostly uses plants and microbes. Hence, the use of microbial nanotechnology in agriculture and plant science is the main emphasis of this review. The present review highlights the methods of biological synthesis of nanoparticles available with a major focus on microbially synthesized nanoparticles, parameters and biochemistry involved. Further, it takes into account the genetic engineering and synthetic biology involved in microbial nanobiosynthesis to the construction of microbial nanofactories.
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Affiliation(s)
- Sofia Sharief Khan
- Department of Biotechnology, Shri Mata Vaishno Devi University, Katra, 182320, Jammu and Kashmir, India
| | - Divjot Kour
- Department of Microbiology, Akal College of Basic Sciences, Eternal University, Baru Sahib, Sirmour, 173101, Himachal Pradesh, India
| | - Tanvir Kaur
- Department of Genetics, Plant Breeding and Biotechnology, Dr. Khem Singh Gill Akal College of Agriculture, Eternal University, Baru Sahib, Sirmour, 173101, Himachal Pradesh, India
| | - Anjali Sharma
- Department of Biotechnology and Genetics, Jain University, Bengaluru, 560069, Karnataka, India
- Department of Allied Healthcare and Sciences, Vivekananda Global University, Jaipur, 303012, Rajasthan, India
| | - Sanjeev Kumar
- Department of Genetics and Plant Breeding, Faculty of Agricultural Sciences, GLA University, Mathura, Uttar Pradesh, India
| | - Shilpa Kumari
- Department of Physics, Rayat Bahra University, Mohali, 140105, Punjab, India
| | - Seema Ramniwas
- Department of Biotechnology, University Centre for Research and Development, Chandigarh University, Gharuan, Mohali, 140413, Punjab, India
| | - Shaveta Singh
- Dolphin PG College of Life Sciences, Chunni Kalan, Fatehgarh Sahib, Punjab, India
| | - Rajeshwari Negi
- Department of Genetics, Plant Breeding and Biotechnology, Dr. Khem Singh Gill Akal College of Agriculture, Eternal University, Baru Sahib, Sirmour, 173101, Himachal Pradesh, India
| | - Babita Sharma
- Department of Microbiology, Akal College of Basic Sciences, Eternal University, Baru Sahib, Sirmour, 173101, Himachal Pradesh, India
| | - Tishu Devi
- Government College for Women, Parade, Jammu, Jammu and Kashmir, India
| | - Chandresh Kumari
- Faculty of Applied Sciences and Biotechnology, Shoolini University, Vill-Bhajhol, Solan, 173229, Himachal Pradesh, India
| | - Harpreet Kour
- Department of Botany, University of Jammu, Jammu, 180006, Jammu and Kashmir, India
| | - Manpreet Kaur
- Department of Physics, IEC University, Baddi, Solan, 174103, Himachal Pradesh, India
| | - Ashutosh Kumar Rai
- Department of Biochemistry, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Kingdom of Saudi Arabia
| | - Sangram Singh
- Department of Biochemistry, Dr. Ram Manohar Lohia Avadh University, Faizabad, Uttar Pradesh, India
| | - Shafaq Rasool
- Department of Biotechnology, Shri Mata Vaishno Devi University, Katra, 182320, Jammu and Kashmir, India
| | - Ajar Nath Yadav
- Department of Genetics, Plant Breeding and Biotechnology, Dr. Khem Singh Gill Akal College of Agriculture, Eternal University, Baru Sahib, Sirmour, 173101, Himachal Pradesh, India.
- Faculty of Health and Life Sciences, INTI International University, Persiaran Perdana BBN, Putra Nilai, 71800, Nilai, Negeri Sembilan, Malaysia.
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Schwarz IA, Alsaqri B, Lekbach Y, Henry K, Gorman S, Woodard T, Dion L, Real L, Holmes DE, Smith JA, Lovley DR. Lack of physiological evidence for cytochrome filaments functioning as conduits for extracellular electron transfer. mBio 2024; 15:e0069024. [PMID: 38717196 PMCID: PMC11077965 DOI: 10.1128/mbio.00690-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 05/12/2024] Open
Abstract
Extracellular cytochrome filaments are proposed to serve as conduits for long-range extracellular electron transfer. The primary functional physiological evidence has been the reported inhibition of Geobacter sulfurreducens Fe(III) oxide reduction when the gene for the filament-forming cytochrome OmcS is deleted. Here we report that the OmcS-deficient strain from that original report reduces Fe(III) oxide as well as the wild-type, as does a triple mutant in which the genes for the other known filament-forming cytochromes were also deleted. The triple cytochrome mutant displayed filaments with the same 3 nm diameter morphology and conductance as those produced by Escherichia coli heterologously expressing the G. sulfurreducens PilA pilin gene. Fe(III) oxide reduction was inhibited when the pilin gene in cytochrome-deficient mutants was modified to yield poorly conductive 3 nm diameter filaments. The results are consistent with the concept that 3 nm diameter electrically conductive pili (e-pili) are required for G. sulfurreducens long-range extracellular electron transfer. In contrast, rigorous physiological functional evidence is lacking for cytochrome filaments serving as conduits for long-range electron transport. IMPORTANCE Unraveling microbial extracellular electron transfer mechanisms has profound implications for environmental processes and advancing biological applications. This study on Geobacter sulfurreducens challenges prevailing beliefs on cytochrome filaments as crucial components thought to facilitate long-range electron transport. The discovery of an OmcS-deficient strain's unexpected effectiveness in Fe(III) oxide reduction prompted a reevaluation of the key conduits for extracellular electron transfer. By exploring the impact of genetic modifications on G. sulfurreducens' performance, this research sheds light on the importance of 3-nm diameter electrically conductive pili in Fe(III) oxide reduction. Reassessing these mechanisms is essential for uncovering the true drivers of extracellular electron transfer in microbial systems, offering insights that could revolutionize applications across diverse fields.
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Affiliation(s)
- Ingrid A. Schwarz
- Department of Biomolecular Sciences, Central Connecticut State University, New Britain, Connecticut, USA
| | - Baha Alsaqri
- Department of Biomolecular Sciences, Central Connecticut State University, New Britain, Connecticut, USA
| | - Yassir Lekbach
- Department of Microbiology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
| | - Kathryn Henry
- Department of Physical and Biological Sciences, Western New England University, Springfield, Massachusetts, USA
| | - Sydney Gorman
- Department of Physical and Biological Sciences, Western New England University, Springfield, Massachusetts, USA
| | - Trevor Woodard
- Department of Microbiology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
| | - Laura Dion
- Department of Physical and Biological Sciences, Western New England University, Springfield, Massachusetts, USA
| | - Lauren Real
- Department of Biomolecular Sciences, Central Connecticut State University, New Britain, Connecticut, USA
| | - Dawn E. Holmes
- Department of Microbiology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
- Department of Physical and Biological Sciences, Western New England University, Springfield, Massachusetts, USA
| | - Jessica A. Smith
- Department of Biomolecular Sciences, Central Connecticut State University, New Britain, Connecticut, USA
- Department of Microbiology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
| | - Derek R. Lovley
- Department of Microbiology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
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3
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Guo W, Chen Y, Cui L, Xu N, Wang M, Sun Y, Yan Y. Nano-hydroxyapatite/carbon nanotube: An excellent anode modifying material for improving the power output and diclofenac sodium removal of microbial fuel cells. Bioelectrochemistry 2023; 154:108523. [PMID: 37478753 DOI: 10.1016/j.bioelechem.2023.108523] [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: 04/27/2023] [Revised: 07/06/2023] [Accepted: 07/13/2023] [Indexed: 07/23/2023]
Abstract
Anode material and surface properties have a crucial impact on the performance of MFCs. Designing and fabricating various modified carbon-based anodes with functional materials is an effective strategy to improve anode performance in MFCs. Anode materials with excellent bioaffinity can promote bacterial attachment, growth, and extracellular electron transfer. In this study, positively charged nano hydroxyapatite (nHA) with remarkable biocompatibility combined with carbon nanotubes (CNTs) with unique structure and high conductivity were used as anode modifying material. The nHA/CNTs modified carbon brush (CB) exhibited improved bacteria adsorption capacity, electrochemical activity and reticular porous structure, thus providing abundant sites and biocompatible microenvironment for the attachment and growth of functional microbial and accelerating extracellular electron transfer. Consequently, the nHA/CNTs/CB-MFCs achieved the maximum power density of 4.50 ± 0.23 mW m-2, which was 1.93 times higher than that of the CB-MFCs. Furthermore, diclofenac sodium (DS), which is a widely used anti-inflammatory drug and is also a persistent toxic organic pollutant constituting a serious threat to public health, was used as the model organic pollutant. After 322 days of long-term operation, enhanced diclofenac sodium removal efficiency and simultaneous bioelectricity generation were realized in nHA/CNTs/CB-MFCs, benefiting from the mature biofilm and the diverse functional microorganisms revealed by microbial community analysis. The nHA/CNTs/CB anode with outstanding bioaffinity, electrochemical activity and porous structure presents great potential for the fabrication of high-performance anodes in MFCs.
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Affiliation(s)
- Wei Guo
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003, People's Republic of China.
| | - Yingying Chen
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003, People's Republic of China
| | - Liang Cui
- Audit affairs Department, Xinxiang Medical University, Xinxiang 453003, People's Republic of China
| | - Na Xu
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003, People's Republic of China
| | - Mengmeng Wang
- School of Pharmacy, Xinxiang Medical University, Xinxiang 453003, People's Republic of China
| | - Yahui Sun
- School of Pharmacy, Xinxiang Medical University, Xinxiang 453003, People's Republic of China
| | - Yunhui Yan
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan 453003, People's Republic of China.
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Boucher DG, Carroll E, Nguyen ZA, Jadhav RG, Simoska O, Beaver K, Minteer SD. Bioelectrocatalytic Synthesis: Concepts and Applications. Angew Chem Int Ed Engl 2023; 62:e202307780. [PMID: 37428529 DOI: 10.1002/anie.202307780] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/08/2023] [Accepted: 07/10/2023] [Indexed: 07/11/2023]
Abstract
Bioelectrocatalytic synthesis is the conversion of electrical energy into value-added products using biocatalysts. These methods merge the specificity and selectivity of biocatalysis and energy-related electrocatalysis to address challenges in the sustainable synthesis of pharmaceuticals, commodity chemicals, fuels, feedstocks and fertilizers. However, the specialized experimental setups and domain knowledge for bioelectrocatalysis pose a significant barrier to adoption. This review introduces key concepts of bioelectrosynthetic systems. We provide a tutorial on the methods of biocatalyst utilization, the setup of bioelectrosynthetic cells, and the analytical methods for assessing bioelectrocatalysts. Key applications of bioelectrosynthesis in ammonia production and small-molecule synthesis are outlined for both enzymatic and microbial systems. This review serves as a necessary introduction and resource for the non-specialist interested in bioelectrosynthetic research.
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Affiliation(s)
- Dylan G Boucher
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Emily Carroll
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Zachary A Nguyen
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Rohit G Jadhav
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Olja Simoska
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
| | - Kevin Beaver
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Shelley D Minteer
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
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5
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Zhou H, Xuanyuan X, Lv X, Wang J, Feng K, Chen C, Ma J, Xing D. Mechanisms of magnetic sensing and regulating extracellular electron transfer of electroactive bacteria under magnetic fields. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 895:165104. [PMID: 37356761 DOI: 10.1016/j.scitotenv.2023.165104] [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: 04/11/2023] [Revised: 06/05/2023] [Accepted: 06/22/2023] [Indexed: 06/27/2023]
Abstract
Electroactive bacteria can display notable plasticity in their response to magnetic field (MF), which prompted bioelectrochemical system as promising candidates for magnetic sensor applications. In this study, we explored the sensing and stimulatory effect of MF on current generation by Geobacter sulfurreducens, and elucidated the related molecular mechanism at the transcriptomic level. MF treatment significantly enhanced electricity generation and overall energy efficiency of G. sulfurreducens by 50 % and 22 %, respectively. The response of current to MFs was instantaneous and reversible. Cyclic voltammetry analysis of the anode biofilm revealed that the redox couples changed from -0.31 to -0.39 V (vs. Ag/AgCl), suggesting that MFs could alter electron transfer related components. Differential gene expression analysis further verified this hypothesis, genes associated with electron transfer were upregulated in G. sulfurreducens under MF treatment relative to the control group, specifically, genes encoding periplasmic c-type cytochromes (ppcA and ppcD), outer membrane cytochrome (omcF, omcZ, omcB), pili (pilA-C, pilM, and pilV2), and ribosome. The enhanced bacterial extracellular electron transfer process was also linked to the overexpression of the NADH dehydrogenase I subunit, the ABC transporter, transcriptional regulation, and ATP synthase. Overall, our findings shed light on the molecular mechanism underlying the effects of magnetic field stimuli on EAB and provide a theoretical basis for its further application in magnetic sensors and other biological system.
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Affiliation(s)
- Huihui Zhou
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China
| | - Xianwen Xuanyuan
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China
| | - Xiaowei Lv
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China
| | - Jing Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China
| | - Kun Feng
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China
| | - Chuan Chen
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China
| | - Defeng Xing
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China.
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6
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Jiang J, He P, Luo Y, Peng Z, Jiang Y, Hu Y, Qi L, Dong X, Dong Y, Shi L. The varied roles of pilA-N, omcE, omcS, omcT, and omcZ in extracellular electron transfer by Geobacter sulfurreducens. Front Microbiol 2023; 14:1251346. [PMID: 37881251 PMCID: PMC10597711 DOI: 10.3389/fmicb.2023.1251346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 09/25/2023] [Indexed: 10/27/2023] Open
Abstract
Geobacter sulfurreducens mediates extracellular electron transfer (EET) reactions with different substrates, such as solid-phase Fe(III)-containing minerals, anodes and the cells of Geobacter metallireducens. To compare their roles in EET, the pilA-N, omcE, omcS, omcT and omcZ genes of G. sulfurreducens were systematically deleted. All mutants showed impaired and varied ability to form biofilms on nonconductive surface. Deletion of omcE also impaired bacterial ability to reduce ferrihydrite, but its impacts on the ability for anode reduction and the co-culture of G. metallireducens-G. sulfurreducens were minimal. The mutant without omcS showed diminished ability to reduce ferrihydrite and to form the co-culture, but was able to regain its ability to reduce anodes. Deletion of omcT, omcZ or pilA-N alone impaired bacterial ability to reduce ferrihydrite and anodes and to form the co-culture. Deletion of all tested genes abolished bacterial ability to reduce ferrihydrite and anodes. Triple-deletion of all omcS, omcT and omcZ abolished the ability of G. sulfurreducens to co-culture with G. metallireducens. However, deletion of only omcZ or pilA-N or both omcS and omcT abolished the ability of G. sulfurreducens without hydrogenase gene hybL to co-culture with G. metallireducens, which show their indispensable roles in direct electron transfer from G. metallireducens to G. sulfurreducens. Thus, the roles of pilA-N, omcE, omcS, omcT and omcZ for G. sulfurreducens in EET vary substantially, which also suggest that possession of PilA-N and multiple cytochromes of different structures enables G. sulfurreducens to mediate EET reactions efficiently with substrates of different properties.
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Affiliation(s)
- Jie Jiang
- School of Environmental Studies, China University of Geosciences-Wuhan, Wuhan, China
| | - Pengchen He
- School of Environmental Studies, China University of Geosciences-Wuhan, Wuhan, China
| | - Ying Luo
- School of Environmental Studies, China University of Geosciences-Wuhan, Wuhan, China
| | - Zhaofeng Peng
- School of Environmental Studies, China University of Geosciences-Wuhan, Wuhan, China
| | - Yongguang Jiang
- School of Environmental Studies, China University of Geosciences-Wuhan, Wuhan, China
| | - Yidan Hu
- School of Environmental Studies, China University of Geosciences-Wuhan, Wuhan, China
| | - Lei Qi
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiuzhu Dong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yiran Dong
- School of Environmental Studies, China University of Geosciences-Wuhan, Wuhan, China
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences-Wuhan, Wuhan, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, Ministry of Ecology and Environment, China University of Geosciences-Wuhan, Wuhan, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences-Wuhan, Wuhan, China
| | - Liang Shi
- School of Environmental Studies, China University of Geosciences-Wuhan, Wuhan, China
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences-Wuhan, Wuhan, China
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, Ministry of Ecology and Environment, China University of Geosciences-Wuhan, Wuhan, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences-Wuhan, Wuhan, China
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Xiong W, Peng Y, Ma W, Xu X, Zhao Y, Wu J, Tang R. Microalgae-material hybrid for enhanced photosynthetic energy conversion: a promising path towards carbon neutrality. Natl Sci Rev 2023; 10:nwad200. [PMID: 37671320 PMCID: PMC10476897 DOI: 10.1093/nsr/nwad200] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 05/10/2023] [Accepted: 07/02/2023] [Indexed: 09/07/2023] Open
Abstract
Photosynthetic energy conversion for high-energy chemicals generation is one of the most viable solutions in the quest for sustainable energy towards carbon neutrality. Microalgae are fascinating photosynthetic organisms, which can directly convert solar energy into chemical energy and electrical energy. However, microalgal photosynthetic energy has not yet been applied on a large scale due to the limitation of their own characteristics. Researchers have been inspired to couple microalgae with synthetic materials via biomimetic assembly and the resulting microalgae-material hybrids have become more robust and even perform new functions. In the past decade, great progress has been made in microalgae-material hybrids, such as photosynthetic carbon dioxide fixation, photosynthetic hydrogen production, photoelectrochemical energy conversion and even biochemical energy conversion for biomedical therapy. The microalgae-material hybrid offers opportunities to promote artificially enhanced photosynthesis research and synchronously inspires investigation of biotic-abiotic interface manipulation. This review summarizes current construction methods of microalgae-material hybrids and highlights their implication in energy and health. Moreover, we discuss the current problems and future challenges for microalgae-material hybrids and the outlook for their development and applications. This review will provide inspiration for the rational design of the microalgae-based semi-natural biohybrid and further promote the disciplinary fusion of material science and biological science.
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Affiliation(s)
- Wei Xiong
- School of Chemistry and Chemical Engineering, Nanchang University, Nanchang 330031, China
| | - Yiyan Peng
- School of Chemistry and Chemical Engineering, Nanchang University, Nanchang 330031, China
| | - Weimin Ma
- College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Xurong Xu
- Department of Chemistry, Zhejiang University, Hangzhou 310058, China
- Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou 310027, China
| | - Yueqi Zhao
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China
| | - Jinhui Wu
- State Key Laboratory of Pharmaceutical Biotechnology, Medical School & School of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Ruikang Tang
- Department of Chemistry, Zhejiang University, Hangzhou 310058, China
- Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou 310027, China
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Jin Y, Zhou E, Ueki T, Zhang D, Fan Y, Xu D, Wang F, Lovley DR. Accelerated Microbial Corrosion by Magnetite and Electrically Conductive Pili through Direct Fe 0 -to-Microbe Electron Transfer. Angew Chem Int Ed Engl 2023; 62:e202309005. [PMID: 37525962 DOI: 10.1002/anie.202309005] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/26/2023] [Accepted: 07/31/2023] [Indexed: 08/02/2023]
Abstract
Electrobiocorrosion, the process in which microbes extract electrons from metallic iron (Fe0 ) through direct Fe0 -microbe electrical connections, is thought to contribute to the costly corrosion of iron-containing metals that impacts many industries. However, electrobiocorrosion mechanisms are poorly understood. We report here that electrically conductive pili (e-pili) and the conductive mineral magnetite play an important role in the electron transfer between Fe0 and Geobacter sulfurreducens, the first microbe in which electrobiocorrosion has been rigorously documented. Genetic modification to express poorly conductive pili substantially diminished corrosive pitting and rates of Fe0 -to-microbe electron flux. Magnetite reduced resistance to electron transfer, increasing corrosion currents and intensifying pitting. Studies with mutants suggested that the magnetite promoted electron transfer in a manner similar to the outer-surface c-type cytochrome OmcS. These findings, and the fact that magnetite is a common product of iron corrosion, suggest a potential positive feedback loop of magnetite produced during corrosion further accelerating electrobiocorrosion. The interactions of e-pili, cytochromes, and magnetite demonstrate mechanistic complexities of electrobiocorrosion, but also provide insights into detecting and possibly mitigating this economically damaging process.
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Affiliation(s)
- Yuting Jin
- Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education), Northeastern University, 110819, Shenyang, China
- Shenyang National Laboratory for Materials Science, Northeastern University, 110819, Shenyang, China
| | - Enze Zhou
- Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education), Northeastern University, 110819, Shenyang, China
- Shenyang National Laboratory for Materials Science, Northeastern University, 110819, Shenyang, China
| | - Toshiyuki Ueki
- Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education), Northeastern University, 110819, Shenyang, China
- Shenyang National Laboratory for Materials Science, Northeastern University, 110819, Shenyang, China
| | - Danni Zhang
- Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education), Northeastern University, 110819, Shenyang, China
- Shenyang National Laboratory for Materials Science, Northeastern University, 110819, Shenyang, China
| | - Yongqiang Fan
- Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education), Northeastern University, 110819, Shenyang, China
- Shenyang National Laboratory for Materials Science, Northeastern University, 110819, Shenyang, China
| | - Dake Xu
- Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education), Northeastern University, 110819, Shenyang, China
- Shenyang National Laboratory for Materials Science, Northeastern University, 110819, Shenyang, China
| | - Fuhui Wang
- Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education), Northeastern University, 110819, Shenyang, China
| | - Derek R Lovley
- Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education), Northeastern University, 110819, Shenyang, China
- Shenyang National Laboratory for Materials Science, Northeastern University, 110819, Shenyang, China
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9
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Abstract
Extracellular electron transfer (EET) is the physiological process that enables the reduction or oxidation of molecules and minerals beyond the surface of a microbial cell. The first bacteria characterized with this capability were Shewanella and Geobacter, both reported to couple their growth to the reduction of iron or manganese oxide minerals located extracellularly. A key difference between EET and nearly every other respiratory activity on Earth is the need to transfer electrons beyond the cell membrane. The past decade has resolved how well-conserved strategies conduct electrons from the inner membrane to the outer surface. However, recent data suggest a much wider and less well understood collection of mechanisms enabling electron transfer to distant acceptors. This review reflects the current state of knowledge from Shewanella and Geobacter, specifically focusing on transfer across the outer membrane and beyond-an activity that enables reduction of highly variable minerals, electrodes, and even other organisms.
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Affiliation(s)
- J A Gralnick
- BioTechnology Institute and Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA; ,
| | - D R Bond
- BioTechnology Institute and Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA; ,
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10
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Su H, Yan X, Zhao Q, Liao C, Tian L, Wang Z, Wan Y, Li N, Wang X. Layered Design of a Highly Repeatable Electroactive Biofilm for a Standardized Biochemical Oxygen Demand Sensor. ACS Sens 2023; 8:2383-2390. [PMID: 37249569 DOI: 10.1021/acssensors.3c00583] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Microbial electrochemical sensors are promising to monitor bioavailable organics in real environments, but their application is restricted by the unpredictable performance of the electroactive biofilm (EAB), which is randomly acclimated from environmental microflora. With a long-term stable EAB as a template, we successfully designed EAB (DEAB) by the sequential growth of Geobacter anodireducens and automatched microbes, achieving a reproducible high current than those naturally acclimated from wastewater (NEAB). Pre-inoculation of planktonic aerobes as oxygen bioscavengers was necessary to ensure the colonization of Geobacter in the inner layer, and the abundant Geobacter (50%) in DEAB guaranteed 4 times higher current density with a 15-fold smaller variation among 20 replicates than those of NEAB. The sensor constructed with DEAB exhibited a shorter measuring time and a precise biochemical oxygen demand (BOD) measurement with acetate, real domestic wastewater, and supernatant of anaerobic digestion. Here, we for the first time proposed an applicable strategy to standardize EABs for BOD sensors, which is also crucial to ensure a stable performance of all bioelectrochemical technologies.
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Affiliation(s)
- Huijuan Su
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Xuejun Yan
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Qian Zhao
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Chengmei Liao
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Lili Tian
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Ziyuan Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Yuxuan Wan
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Nan Li
- School of Environmental Science and Engineering, Tianjin University, No. 35 Yaguan Road, Jinnan District, Tianjin 300350, China
| | - Xin Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
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11
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Liu Y, Yue T, Liu L, Zhang B, Feng H, Li S, Liu X, Dai Y, Zhao J. Molecular assembly of extracellular polymeric substances regulating aggregation of differently charged nanoplastics and subsequent interactions with bacterial membrane. JOURNAL OF HAZARDOUS MATERIALS 2023; 457:131825. [PMID: 37315410 DOI: 10.1016/j.jhazmat.2023.131825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 06/05/2023] [Accepted: 06/08/2023] [Indexed: 06/16/2023]
Abstract
Extracellular polymeric substances (EPS) represent an interface between microbial cells and aquatic environment, where nanoplastics acquire coatings to alter their fate and toxicity. However, little is known about molecular interactions governing modification of nanoplastics at biological interfaces. Molecular dynamics simulations combining experiments were conducted to investigate assembly of EPS and its regulatory roles in the aggregation of differently charged nanoplastics and interactions with bacterial membrane. Driven by hydrophobic and electrostatic interactions, EPS formed micelle-like supramolecular structures with hydrophobic core and amphiphilic exterior. Different components, depending on their hydrophobicity and charge, were found to promote or suppress EPS assembly. Neutral and hydrophobic nanoplastics showed unbiased adsorption of EPS species, while cationic and anionic nanoplastics were distinct and attracted specific molecules of opposite charges. Compared with isolated EPS, assembled EPS concealed hydrophobic groups to be less adsorbed by nanoplastics. Aggregation of nanoplastics was alleviated by EPS due to electrostatic repulsion plus steric hindrance. ESP suppressed binding of cationic nanoplastics to the bacterial membrane through reducing the surface charge. Neutral and anionic nanoplastics showed weak membrane association, but their binding interactions were promoted by EPS. The structural details revealed here provided molecular level insights into modifications of nanoplastics at the eco-environment interface.
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Affiliation(s)
- Yingjie Liu
- Institute of Coastal Environmental Pollution Control, Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
| | - Tongtao Yue
- Institute of Coastal Environmental Pollution Control, Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
| | - Lu Liu
- Institute of Coastal Environmental Pollution Control, Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
| | - Bowen Zhang
- Institute of Coastal Environmental Pollution Control, Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
| | - Hao Feng
- College of Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Shixin Li
- Joint International Research Laboratory of Agriculture and Agri-product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Xia Liu
- Institute of Coastal Environmental Pollution Control, Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
| | - Yanhui Dai
- Institute of Coastal Environmental Pollution Control, Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
| | - Jian Zhao
- Institute of Coastal Environmental Pollution Control, Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
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12
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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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13
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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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14
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Schneider H, Lai B, Krömer J. Utilizing Cyanobacteria in Biophotovoltaics: An Emerging Field in Bioelectrochemistry. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2023; 183:281-302. [PMID: 36441187 DOI: 10.1007/10_2022_212] [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: 11/29/2022]
Abstract
Anthropogenic global warming is driven by the increasing energy demand and the still dominant use of fossil energy carriers to meet these needs. New carbon-neutral energy sources are urgently needed to solve this problem. Biophotovoltaics, a member of the so-called bioelectrochemical systems family, will provide an important piece of the energy puzzle. It aims to harvest the electrons from sunlight-driven water splitting using the natural oxygenic photosystem (e.g., of cyanobacteria) and utilize them in the form of, e.g., electricity or hydrogen. Several key aspects of biophotovoltaics have been intensively studied in recent years like physicochemical properties of electrodes or efficient wiring of microorganisms to electrodes. Yet, the exact mechanisms of electron transfer between the biocatalyst and the electrode remain unresolved today. Most research is conducted on microscale reactors generating small currents over short time-scales, but multiple experiments have shown biophotovoltaics great potential with lab-scale reactors producing currents over weeks to months. Although biophotovoltaics is still in its infancy with many open research questions to be addressed, new promising results from various labs around the world suggest an important opportunity for biophotovoltaics in the decades to come. In this chapter, we will introduce the concept of biophotovoltaics, summarize its recent key progress, and finally critically discuss the potentials and challenges for future rational development of biophotovoltaics.
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Affiliation(s)
- Hans Schneider
- Department of Solar Materials, Helmholtz Center for Environmental Research, Leipzig, Germany.
| | - Bin Lai
- Department of Solar Materials, Helmholtz Center for Environmental Research, Leipzig, Germany
| | - Jens Krömer
- Department of Solar Materials, Helmholtz Center for Environmental Research, Leipzig, Germany
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15
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Application of Low-Cost Plant-Derived Carbon Dots as a Sustainable Anode Catalyst in Microbial Fuel Cells for Improved Wastewater Treatment and Power Output. Catalysts 2022. [DOI: 10.3390/catal12121580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022] Open
Abstract
Microbial fuel cells (MFC) can generate electric energy from wastewater which can be enhanced further by anode catalysts. The recovery of electrons produced by oxidation of organics catalyzed by bacteria in the anode was enhanced when carbon dots(CDs) were added into the MFC. In this present study, a novel strategy for designing anode material and the fabrication of a high-efficient and environmentally friendly anode for energy generation from wastewater was reported. The CDs were synthesized by the pyrolysis of a peanut shell at the temperature of 250 °C for 2 h with a heating rate of 10 °C min−1. Thus synthesized CDs were characterized by transmission electron microscopy (TEM), UV/Vis spectroscopy, and fluorescence spectroscopy. The TEM analysis showed morphology with an average size of 1.62 nm. The UV/Vis absorbance of the CDs shows a wide absorption band without a characteristic peak. The excitation spectrum of CDs recorded at the emission wavelength of 440 nm exhibits a peak around 320 nm. CDs were investigated as an anode material in a MFC utilizing acetate as the organic substrate. The average chemical oxygen demand (COD) removal in closed circuit operation mode was 89%. The maximum power density production (7.2 W/m3) was observed in MFC containing 1 mg/cm2 CD-impregnated anode (CDsIA). The CDsIA provides the ability to promote efficient biofilm formation. These results emphasize the application of CD-based electrodes in MFCs for the simultaneous treatment of wastewater and electricity generation while also providing additional benefits.
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16
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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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17
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An Overview of Emerging Cyanide Bioremediation Methods. Processes (Basel) 2022. [DOI: 10.3390/pr10091724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022] Open
Abstract
Cyanide compounds are hazardous compounds which are extremely toxic to living organisms, especially free cyanide in the form of hydrogen cyanide gas (HCN) and cyanide ion (CN−). These cyanide compounds are metabolic inhibitors since they can tightly bind to the metals of metalloenzymes. Anthropogenic sources contribute significantly to CN− contamination in the environment, more specifically to surface and underground waters. The treatment processes, such as chemical and physical treatment processes, have been implemented. However, these processes have drawbacks since they generate additional contaminants which further exacerbates the environmental pollution. The biological treatment techniques are mostly overlooked as an alternative to the conventional physical and chemical methods. However, the recent research has focused substantially on this method, with different reactor configurations that were proposed. However, minimal attention was given to the emerging technologies that sought to accelerate the treatment with a subsequent resource recovery from the process. Hence, this review focuses on the recent emerging tools that can be used to accelerate cyanide biodegradation. These tools include, amongst others, electro-bioremediation, anaerobic biodegradation and the use of microbial fuel cell technology. These processes were demonstrated to have the possibility of producing value-added products, such as biogas, co-factors of neurotransmitters and electricity from the treatment process.
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18
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19
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20
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Thapa BS, Kim T, Pandit S, Song YE, Afsharian YP, Rahimnejad M, Kim JR, Oh SE. Overview of electroactive microorganisms and electron transfer mechanisms in microbial electrochemistry. BIORESOURCE TECHNOLOGY 2022; 347:126579. [PMID: 34921921 DOI: 10.1016/j.biortech.2021.126579] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/10/2021] [Accepted: 12/11/2021] [Indexed: 06/14/2023]
Abstract
Electroactive microorganisms acting as microbial electrocatalysts have intrinsic metabolisms that mediate a redox potential difference between solid electrodes and microbes, leading to spontaneous electron transfer to the electrode (exo-electron transfer) or electron uptake from the electrode (endo-electron transfer). These microbes biochemically convert various organic and/or inorganic compounds to electricity and/or biochemicals in bioelectrochemical systems (BESs) such as microbial fuel cells (MFCs) and microbial electrosynthesis cells (MECs). For the past two decades, intense studies have converged to clarify electron transfer mechanisms of electroactive microbes in BESs, which thereby have led to improved bioelectrochemical performance. Also, many novel exoelectrogenic eukaryotes as well as prokaryotes with electroactive properties are being continuously discovered. This review presents an overview of electroactive microorganisms (bacteria, microalgae and fungi) and their exo- and endo-electron transfer mechanisms in BESs for optimizing and advancing bioelectrochemical techniques.
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Affiliation(s)
- Bhim Sen Thapa
- Department of Biological Environment, Kangwon National University, Chuncheon, Gangwondo 24341, Republic of Korea
| | - Taeyoung Kim
- Department of Environmental Engineering, Chosun University, Gwangju 61452, Republic of Korea
| | - Soumya Pandit
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Greater Noida 201306, India
| | - Young Eun Song
- Advanced Biofuel and Bioproducts Process Development Unit, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA
| | - Yasamin Pesaran Afsharian
- Biofuel and Renewable Energy Research Center, Chemical Engineering Department, Babol Noshirvani University of Technology, Babol, Iran
| | - Mostafa Rahimnejad
- Biofuel and Renewable Energy Research Center, Chemical Engineering Department, Babol Noshirvani University of Technology, Babol, Iran
| | - Jung Rae Kim
- School of Chemical Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Sang-Eun Oh
- Department of Biological Environment, Kangwon National University, Chuncheon, Gangwondo 24341, Republic of Korea.
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21
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Ueki T, Lovley DR. Desulfovibrio vulgaris as a model microbe for the study of corrosion under sulfate-reducing conditions. MLIFE 2022; 1:13-20. [PMID: 38818327 PMCID: PMC10989807 DOI: 10.1002/mlf2.12018] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/05/2022] [Accepted: 03/07/2022] [Indexed: 06/01/2024]
Abstract
Corrosion of iron-containing metals under sulfate-reducing conditions is an economically important problem. Microbial strains now known as Desulfovibrio vulgaris served as the model microbes in many of the foundational studies that developed existing models for the corrosion of iron-containing metals under sulfate-reducing conditions. Proposed mechanisms for corrosion by D. vulgaris include: (1) H2 consumption to accelerate the oxidation of Fe0 coupled to the reduction of protons to H2; (2) production of sulfide that combines with ferrous iron to form iron sulfide coatings that promote H2 production; (3) moribund cells release hydrogenases that catalyze Fe0 oxidation with the production of H2; (4) direct electron transfer from Fe0 to cells; and (5) flavins serving as an electron shuttle for electron transfer between Fe0 and cells. The demonstrated possibility of conducting transcriptomic and proteomic analysis of cells growing on metal surfaces suggests that similar studies on D. vulgaris corrosion biofilms can aid in identifying proteins that play an important role in corrosion. Tools for making targeted gene deletions in D. vulgaris are available for functional genetic studies. These approaches, coupled with instrumentation for the detection of low concentrations of H2, and proven techniques for evaluating putative electron shuttle function, are expected to make it possible to determine which of the proposed mechanisms for D. vulgaris corrosion are most important.
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Affiliation(s)
- Toshiyuki Ueki
- Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, Electrobiomaterials InstituteNortheastern UniversityShenyangChina
| | - Derek R. Lovley
- Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, Electrobiomaterials InstituteNortheastern UniversityShenyangChina
- Department of Microbiology University of MassachusettsAmherstMAUSA
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22
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Zhuang Z, Yang G, Zhuang L. Exopolysaccharides matrix affects the process of extracellular electron transfer in electroactive biofilm. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150713. [PMID: 34606863 DOI: 10.1016/j.scitotenv.2021.150713] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/19/2021] [Accepted: 09/27/2021] [Indexed: 05/20/2023]
Abstract
The applications of bioelectrochemical systems (BESs) in the field of environment and energy are achieved through the bioelectrocatalytic process of electroactive biofilms. As a primary component of biofilm, the role of exopolysaccharides in electroactive biofilm in BESs is poorly understood. This study constructed an exopolysaccharides-deficient Geobacter sulfurreducens-based BES to explore the role of exopolysaccharides in electroactive biofilm. Compared with the wild type, the mutant biofilm expressing less exopolysaccharides decreased the capacity of current generation. In the mutant biofilm, the content of exopolysaccharides decreased significantly, resulting in a thinner biofilm and lower cell viability compared with the wild-type biofilm. However, the mutant with overexpressed pili developed a mature biofilm with extended time, which indicating the importance of exopolysaccharides for early biofilm formation and the compensatory role of pili in biofilm formation. The mutant biofilm had less content of c-type cytochromes (c-Cyts) and lower electrochemical activity of extracellular polymeric substances than the wild-type biofilm, suggesting a function of exopolysaccharides anchoring extracellular c-Cyts that essential to extracellular electron transfer (EET) in electroactive biofilms. Our findings demonstrated the essential role of exopolysaccharides in the process of EET in electroactive biofilm, which contributed to a better understanding and optimization of the performance of BESs.
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Affiliation(s)
- Zheng Zhuang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China
| | - Guiqin Yang
- 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.
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Zhu X, Wang X, Li N, Wang Q, Liao C. Bioelectrochemical system for dehalogenation: A review. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 293:118519. [PMID: 34793908 DOI: 10.1016/j.envpol.2021.118519] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/26/2021] [Accepted: 11/13/2021] [Indexed: 06/13/2023]
Abstract
Halogenated organic compounds are persistent pollutants, whose persistent contamination and rapid spread seriously threaten human health and the safety of ecosystems. It is difficult to remove them completely by traditional physicochemical techniques. In-situ remediation utilizing bioelectrochemical technology represents a promising strategy for degradation of halogenated organic compounds, which can be achieved through potential modulation. In this review, we summarize the reactor configuration of microbial electrochemical dehalogenation systems and relevant organohalide-respiring bacteria. We also highlight the mechanisms of electrode potential regulation of microbial dehalogenation and the role of extracellular electron transfer in dehalogenation process, and further discuss the application of bioelectrochemical technology in bioremediation of halogenated organic compounds. Therefore, this review summarizes the status of research on microbial electrochemical dehalogenation systems from macroscopic to microscopic levels, providing theoretical support for the development of rapid and efficient in situ bioremediation technologies for halogenated organic compounds contaminated sites, as well as insights for the removal of refractory fluorides.
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Affiliation(s)
- Xuemei Zhu
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin, 300350, China
| | - Xin Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin, 300350, China
| | - Nan Li
- School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin, 300072, China
| | - Qi Wang
- Beijing Construction Engineering Group Environmental Remediation Co. Ltd. and National Engineering Laboratory for Site Remediation Technologies, Beijing, 100015, China
| | - Chengmei Liao
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin, 300350, China.
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24
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Hu Y, Wang Y, Han X, Shan Y, Li F, Shi L. Biofilm Biology and Engineering of Geobacter and Shewanella spp. for Energy Applications. Front Bioeng Biotechnol 2021; 9:786416. [PMID: 34926431 PMCID: PMC8683041 DOI: 10.3389/fbioe.2021.786416] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/18/2021] [Indexed: 01/04/2023] Open
Abstract
Geobacter and Shewanella spp. were discovered in late 1980s as dissimilatory metal-reducing microorganisms that can transfer electrons from cytoplasmic respiratory oxidation reactions to external metal-containing minerals. In addition to mineral-based electron acceptors, Geobacter and Shewanella spp. also can transfer electrons to electrodes. The microorganisms that have abilities to transfer electrons to electrodes are known as exoelectrogens. Because of their remarkable abilities of electron transfer, Geobacter and Shewanella spp. have been the two most well studied groups of exoelectrogens. They are widely used in bioelectrochemical systems (BESs) for various biotechnological applications, such as bioelectricity generation via microbial fuel cells. These applications mostly associate with Geobacter and Shewanella biofilms grown on the surfaces of electrodes. Geobacter and Shewanella biofilms are electrically conductive, which is conferred by matrix-associated electroactive components such as c-type cytochromes and electrically conductive nanowires. The thickness and electroactivity of Geobacter and Shewanella biofilms have a significant impact on electron transfer efficiency in BESs. In this review, we first briefly discuss the roles of planktonic and biofilm-forming Geobacter and Shewanella cells in BESs, and then review biofilm biology with the focus on biofilm development, biofilm matrix, heterogeneity in biofilm and signaling regulatory systems mediating formation of Geobacter and Shewanella biofilms. Finally, we discuss strategies of Geobacter and Shewanella biofilm engineering for improving electron transfer efficiency to obtain enhanced BES performance.
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Affiliation(s)
- Yidan Hu
- Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Yinghui Wang
- Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Xi Han
- Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Yawei Shan
- Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Feng Li
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Liang Shi
- Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geosciences, Wuhan, China.,State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China.,Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan, China.,State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, Ministry of Ecology and Environment, Wuhan, China
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25
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Massazza D, Robledo AJ, Rodriguez Simón CN, Busalmen JP, Bonanni S. Energetics, electron uptake mechanisms and limitations of electroautotrophs growing on biocathodes - A review. BIORESOURCE TECHNOLOGY 2021; 342:125893. [PMID: 34537530 DOI: 10.1016/j.biortech.2021.125893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 08/31/2021] [Accepted: 09/03/2021] [Indexed: 06/13/2023]
Abstract
Electroautotrophs are microorganisms that can take the electrons needed for energy generation, CO2 fixation and other metabolic reactions from a polarized electrode. They have been the focus of intense research for its application in wastewater treatment, bioelectrosynthetic processes and hydrogen generation. As a general trend, current densities produced by the electron uptake of these microorganisms are low, limiting their applicability at large scale. In this work, the electron uptake mechanisms that may operate in electroautotrophs are reviewed, aiming at finding possible causes for this low performance. Biomass yields, growth rates and electron uptake rates observed when these microorganisms use chemical electron donors are compared with those typically obtained with electrodes, to explore limitations and advantages inherent to the electroautotrophic metabolism. Also, the factors affecting biofilm development are analysed to show how interfacial interactions condition bacterial adhesion, biofilm growth and electrons uptake. Finally, possible strategies to overcome these limitations are described.
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Affiliation(s)
- Diego Massazza
- División Ingeniería de Interfases y Bioprocesos, INTEMA (Conicet, Universidad Nacional de Mar del Plata), Av. Colón 10850, Mar del Plata 7600, Argentina
| | - Alejandro Javier Robledo
- División Ingeniería de Interfases y Bioprocesos, INTEMA (Conicet, Universidad Nacional de Mar del Plata), Av. Colón 10850, Mar del Plata 7600, Argentina
| | - Carlos Norberto Rodriguez Simón
- División Ingeniería de Interfases y Bioprocesos, INTEMA (Conicet, Universidad Nacional de Mar del Plata), Av. Colón 10850, Mar del Plata 7600, Argentina
| | - Juan Pablo Busalmen
- División Ingeniería de Interfases y Bioprocesos, INTEMA (Conicet, Universidad Nacional de Mar del Plata), Av. Colón 10850, Mar del Plata 7600, Argentina
| | - Sebastián Bonanni
- División Ingeniería de Interfases y Bioprocesos, INTEMA (Conicet, Universidad Nacional de Mar del Plata), Av. Colón 10850, Mar del Plata 7600, Argentina.
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26
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Yan X, Du Q, Mu Q, Tian L, Wan Y, Liao C, Zhou L, Yan Y, Li N, Logan BE, Wang X. Long-Term Succession Shows Interspecies Competition of Geobacter in Exoelectrogenic Biofilms. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:14928-14937. [PMID: 34676765 DOI: 10.1021/acs.est.1c03010] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Geobacter spp. are well-known exoelectrogenic microorganisms that often predominate acetate-fed biofilms in microbial fuel cells (MFCs) and other bioelectrochemical systems (BESs). By using an amplicon sequence variance analysis (at one nucleotide resolution), we observed a succession between two closely related species (98% similarity in 16S RNA), Geobacter sulfurreducens and Geobacter anodireducens, in the long-term studies (20 months) of MFC biofilms. Geobacter spp. predominated in the near-electrode portion of the biofilm, while the outer layer contained an abundance of aerobes, which may have helped to consume oxygen but reduced the relative abundance of Geobacter. Removal of the outer aerobes by norspermidine washing of biofilms revealed a transition from G. sulfurreducens to G. anodireducens. This succession was also found to occur rapidly in co-cultures in BES tests even in the absence of oxygen, suggesting that oxygen was not a critical factor. G. sulfurreducens likely dominated in early biofilms by its relatively larger cell size and production of extracellular polymeric substances (individual advantages), while G. anodireducens later predominated due to greater cell numbers (quantitative advantage). Our findings revealed the interspecies competition in the long-term evolution of Geobacter genus, providing microscopic insights into Geobacter's niche and competitiveness in complex electroactive microbial consortia.
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Affiliation(s)
- Xuejun Yan
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Qing Du
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Quanhua Mu
- Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China
| | - Lili Tian
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Yuxuan Wan
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Chengmei Liao
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Lean Zhou
- School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha 410114, China
| | - Yuqing Yan
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
| | - Nan Li
- School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Bruce E Logan
- Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Xin Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China
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27
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Generation of High Current Densities in Geobacter sulfurreducens Lacking the Putative Gene for the PilB Pilus Assembly Motor. Microbiol Spectr 2021; 9:e0087721. [PMID: 34585977 PMCID: PMC8557921 DOI: 10.1128/spectrum.00877-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Geobacter sulfurreducens is commonly employed as a model for the study of extracellular electron transport mechanisms in the Geobacter species. Deletion of pilB, which is known to encode the pilus assembly motor protein for type IV pili in other bacteria, has been proposed as an effective strategy for evaluating the role of electrically conductive pili (e-pili) in G. sulfurreducens extracellular electron transfer. In those studies, the inhibition of e-pili expression associated with pilB deletion was not demonstrated directly but was inferred from the observation that pilB deletion mutants produced lower current densities than wild-type cells. Here, we report that deleting pilB did not diminish current production. Conducting probe atomic force microscopy revealed filaments with the same diameter and similar current-voltage response as e-pili harvested from wild-type G. sulfurreducens or when e-pili are expressed heterologously from the G. sulfurreducens pilin gene in Escherichia coli. Immunogold labeling demonstrated that a G. sulfurreducens strain expressing a pilin monomer with a His tag continued to express His tag-labeled filaments when pilB was deleted. These results suggest that a reinterpretation of the results of previous studies on G. sulfurreducens pilB deletion strains may be necessary. IMPORTANCE Geobacter sulfurreducens is a model microbe for the study of biogeochemically and technologically significant processes, such as the reduction of Fe(III) oxides in soils and sediments, bioelectrochemical applications that produce electric current from waste organic matter or drive useful processes with the consumption of renewable electricity, direct interspecies electron transfer in anaerobic digestors and methanogenic soils and sediments, and metal corrosion. Elucidating the phenotypes associated with gene deletions is an important strategy for determining the mechanisms for extracellular electron transfer in G. sulfurreducens. The results reported here demonstrate that we cannot replicate the key phenotype reported for a gene deletion that has been central to the development of models for long-range electron transport in G. sulfurreducens.
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28
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Fujikawa T, Ogura Y, Ishigami K, Kawano Y, Nagamine M, Hayashi T, Inoue K. Unexpected genomic features of high current density-producing Geobacter sulfurreducens strain YM18. FEMS Microbiol Lett 2021; 368:6362602. [PMID: 34472610 DOI: 10.1093/femsle/fnab119] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 08/31/2021] [Indexed: 12/28/2022] Open
Abstract
Geobacter sulfurreducens produces high current densities and it has been used as a model organism for extracellular electron transfer studies. Nine G. sulfurreducens strains were isolated from biofilms formed on an anode poised at -0.2 V (vs SHE) in a bioelectrochemical system in which river sediment was used as an inoculum. The maximum current density of an isolate, strain YM18 (9.29 A/m2), was higher than that of the strain PCA (5.72 A/m2), the type strain of G. sulfurreducens, and comparable to strain KN400 (8.38 A/m2), which is another high current-producing strain of G. sulfurreducens. Genomic comparison of strains PCA, KN400 and YM18 revealed that omcB, xapD, spc and ompJ, which are known to be important genes for iron reduction and current production in PCA, were not present in YM18. In the PCA and KN400 genomes, two and one region(s) encoding CRISPR/Cas systems were identified, respectively, but they were missing in the YM18 genome. These results indicate that there is genetic variation in the key components involved in extracellular electron transfer among G. sulfurreducens strains.
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Affiliation(s)
- Takashi Fujikawa
- Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Yoshitoshi Ogura
- Division of Microbiology, Department of Infectious Medicine, Kurume University School of Medicine, Kurume 830-0011, Fukuoka, Japan
| | - Koki Ishigami
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Yoshihiro Kawano
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Miyuki Nagamine
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Tetsuya Hayashi
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu University, Fukuoka 812-8285, Japan
| | - Kengo Inoue
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan
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29
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Liu X, Walker DJF, Nonnenmann SS, Sun D, Lovley DR. Direct Observation of Electrically Conductive Pili Emanating from Geobacter sulfurreducens. mBio 2021; 12:e0220921. [PMID: 34465020 PMCID: PMC8406130 DOI: 10.1128/mbio.02209-21] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 08/02/2021] [Indexed: 11/20/2022] Open
Abstract
Geobacter sulfurreducens is a model microbe for elucidating the mechanisms for extracellular electron transfer in several biogeochemical cycles, bioelectrochemical applications, and microbial metal corrosion. Multiple lines of evidence previously suggested that electrically conductive pili (e-pili) are an essential conduit for long-range extracellular electron transport in G. sulfurreducens. However, it has recently been reported that G. sulfurreducens does not express e-pili and that filaments comprised of multi-heme c-type cytochromes are responsible for long-range electron transport. This possibility was directly investigated by examining cells, rather than filament preparations, with atomic force microscopy. Approximately 90% of the filaments emanating from wild-type cells had a diameter (3 nm) and conductance consistent with previous reports of e-pili harvested from G. sulfurreducens or heterologously expressed in Escherichia coli from the G. sulfurreducens pilin gene. The remaining 10% of filaments had a morphology consistent with filaments comprised of the c-type cytochrome OmcS. A strain expressing a modified pilin gene designed to yield poorly conductive pili expressed 90% filaments with a 3-nm diameter, but greatly reduced conductance, further indicating that the 3-nm diameter conductive filaments in the wild-type strain were e-pili. A strain in which genes for five of the most abundant outer-surface c-type cytochromes, including OmcS, were deleted yielded only 3-nm-diameter filaments with the same conductance as in the wild type. These results demonstrate that e-pili are the most abundant conductive filaments expressed by G. sulfurreducens, consistent with previous functional studies demonstrating the need for e-pili for long-range extracellular electron transfer. IMPORTANCE Electroactive microbes have significant environmental impacts, as well as applications in bioenergy and bioremediation. The composition, function, and even existence of electrically conductive pili (e-pili) has been one of the most contentious areas of investigation in electromicrobiology, in part because e-pili offer a mechanism for long-range electron transport that does not involve the metal cofactors common in much of biological electron transport. This study demonstrates that e-pili are abundant filaments emanating from Geobacter sulfurreducens, which serves as a model for long-range extracellular electron transfer in direct interspecies electron transfer, dissimilatory metal reduction, microbe-electrode exchange, and corrosion caused by direct electron uptake from Fe(0). The methods described in this study provide a simple strategy for evaluating the distribution of conductive filaments throughout the microbial world with an approach that avoids artifactual production and/or enrichment of filaments that may not be physiologically relevant.
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Affiliation(s)
- Xinying Liu
- Department of Microbiology, University of Massachusetts—Amherst, Amherst, Massachusetts, USA
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing, China
| | - David J. F. Walker
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
| | - Stephen S. Nonnenmann
- Institute for Applied Life Sciences, university of Massachusetts—Amherst, Amherst, Massachusetts, USA
- Department of Mechanical and Industrial Engineering, University of Massachusetts—Amherst, Amherst, Massachusetts, USA
| | - Dezhi Sun
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing, China
| | - Derek R. Lovley
- Department of Microbiology, University of Massachusetts—Amherst, Amherst, Massachusetts, USA
- Institute for Applied Life Sciences, university of Massachusetts—Amherst, Amherst, Massachusetts, USA
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30
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Lovley DR, Holmes DE. Electromicrobiology: the ecophysiology of phylogenetically diverse electroactive microorganisms. Nat Rev Microbiol 2021; 20:5-19. [PMID: 34316046 DOI: 10.1038/s41579-021-00597-6] [Citation(s) in RCA: 176] [Impact Index Per Article: 58.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2021] [Indexed: 02/03/2023]
Abstract
Electroactive microorganisms markedly affect many environments in which they establish outer-surface electrical contacts with other cells and minerals or reduce soluble extracellular redox-active molecules such as flavins and humic substances. A growing body of research emphasizes their broad phylogenetic diversity and shows that these microorganisms have key roles in multiple biogeochemical cycles, as well as the microbiome of the gut, anaerobic waste digesters and metal corrosion. Diverse bacteria and archaea have independently evolved cytochrome-based strategies for electron exchange between the outer cell surface and the cell interior, but cytochrome-free mechanisms are also prevalent. Electrically conductive protein filaments, soluble electron shuttles and non-biological conductive materials can substantially extend the electronic reach of microorganisms beyond the surface of the cell. The growing appreciation of the diversity of electroactive microorganisms and their unique electronic capabilities is leading to a broad range of applications.
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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, China. .,Department of Microbiology, University of Massachusetts, Amherst, MA, USA. .,Institute for Applied Life Sciences (IALS), University of Massachusetts, Amherst, MA, USA.
| | - Dawn E Holmes
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA.,Institute for Applied Life Sciences (IALS), University of Massachusetts, Amherst, MA, USA.,Department of Physical and Biological Sciences, Western New England University, Springfield, MA, USA
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31
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Bio-Electrochemical System Depollution Capabilities and Monitoring Applications: Models, Applicability, Advanced Bio-Based Concept for Predicting Pollutant Degradation and Microbial Growth Kinetics via Gene Regulation Modelling. Processes (Basel) 2021. [DOI: 10.3390/pr9061038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Microbial fuel cells (MFC) are an emerging technology for waste, wastewater and polluted soil treatment. In this manuscript, pollutants that can be treated using MFC systems producing energy are presented. Furthermore, the applicability of MFC in environmental monitoring is described. Common microbial species used, release of genome sequences, and gene regulation mechanisms, are discussed. However, although scaling-up is the key to improving MFC systems, it is still a difficult challenge. Mathematical models for MFCs are used for their design, control and optimization. Such models representing the system are presented here. In such comprehensive models, microbial growth kinetic approaches are essential to designing and predicting a biosystem. The empirical and unstructured Monod and Monod-type models, which are traditionally used, are also described here. Understanding and modelling of the gene regulatory network could be a solution for enhancing knowledge and designing more efficient MFC processes, useful for scaling it up. An advanced bio-based modelling concept connecting gene regulation modelling of specific metabolic pathways to microbial growth kinetic models is presented here; it enables a more accurate prediction and estimation of substrate biodegradation, microbial growth kinetics, and necessary gene and enzyme expression. The gene and enzyme expression prediction can also be used in synthetic and systems biology for process optimization. Moreover, various MFC applications as a bioreactor and bioremediator, and in soil pollutant removal and monitoring, are explored.
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32
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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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34
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Identification of a Diguanylate Cyclase That Facilitates Biofilm Formation on Electrodes by Shewanella oneidensis MR-1. Appl Environ Microbiol 2021; 87:AEM.00201-21. [PMID: 33637573 DOI: 10.1128/aem.00201-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 02/19/2021] [Indexed: 12/29/2022] Open
Abstract
In many bacteria, cyclic diguanosine monophosphate (c-di-GMP), synthesized by diguanylate cyclase (DGC), serves as a second messenger involved in the regulation of biofilm formation. Although studies have suggested that c-di-GMP also regulates the formation of electrochemically active biofilms (EABFs) by Shewanella oneidensis MR-1, DGCs involved in this process remained to be identified. Here, we report that the SO_1646 gene, hereafter named dgcS, is upregulated under medium flow conditions in electrochemical flow cells (EFCs), and its product (DgcS) functions as a major DGC in MR-1. In vitro assays demonstrated that purified DgcS catalyzed the synthesis of c-di-GMP from GTP. Comparisons of intracellular c-di-GMP levels in the wild-type strain and a dgcS deletion mutant (ΔdgcS mutant) showed that production of c-di-GMP was markedly reduced in the ΔdgcS mutant when cells were grown in batch cultures and on electrodes in EFCs. Cultivation of the ΔdgcS mutant in EFCs also revealed that the loss of DgcS resulted in impaired biofilm formation and decreased current generation. These findings demonstrate that MR-1 uses DgcS to synthesize c-di-GMP under medium flow conditions, thereby activating biofilm formation on electrodes.IMPORTANCE Bioelectrochemical systems (BESs) have attracted wide attention owing to their utility in sustainable biotechnology processes, such as microbial fuel cells and electrofermentation systems. In BESs, electrochemically active bacteria (EAB) form biofilms on electrode surfaces, thereby serving as effective catalysts for the interconversion between chemical and electric energy. It is therefore important to understand mechanisms for the formation of biofilm by EAB grown on electrodes. Here, we show that a model EAB, S. oneidensis MR-1, expresses DgcS as a major DGC, thereby activating the formation of biofilms on electrodes via c-di-GMP-dependent signal transduction cascades. The findings presented herein provide the molecular basis for improving electrochemical interactions between EAB and electrodes in BESs. The results also offer molecular insights into how Shewanella regulates biofilm formation on solid surfaces in the natural environment.
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Microbial fuel cells, a renewable energy technology for bio-electricity generation: A mini-review. Electrochem commun 2021. [DOI: 10.1016/j.elecom.2021.107003] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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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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Guo F, Babauta JT, Beyenal H. The effect of additional salinity on performance of a phosphate buffer saline buffered three-electrode bioelectrochemical system inoculated with wastewater. BIORESOURCE TECHNOLOGY 2021; 320:124291. [PMID: 33157437 DOI: 10.1016/j.biortech.2020.124291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 06/11/2023]
Abstract
In bioelectrochemical system (BES), phosphate buffer saline (PBS) is usually used to achieve a suitable pH condition, which also increases electrolyte salinity. A series of factors that change with salinity will affect BES performance. To simplify the scenario, a three-electrode BES is used to investigate how additional salinity affects the performance of a 50 mM PBS-buffered BES. Results demonstrated that current production decreased with increasing salinity and the dominant exoelectrogens were not inhibited with the addition of 200 mM NaCl. The distribution of system resistance was analyzed by electrochemical impedance spectroscopy. Compared to the decreased solution and biofilm resistance, the increased interfacial resistance that accounted for up to 97.8% of total resistance was the dominant reason for the decreased current production with the increasing additional salinity. The effects of additional salinity on acetate degradation and columbic efficiency were also analyzed.
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Affiliation(s)
- Fei Guo
- School of Civil Engineering, Architecture and Environment, Xihua University, Chengdu 610039, China; The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA.
| | - Jerome T Babauta
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA
| | - Haluk Beyenal
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA
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Zhuang Z, Yang G, Mai Q, Guo J, Liu X, Zhuang L. Physiological potential of extracellular polysaccharide in promoting Geobacter biofilm formation and extracellular electron transfer. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 741:140365. [PMID: 32610234 DOI: 10.1016/j.scitotenv.2020.140365] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/17/2020] [Accepted: 06/17/2020] [Indexed: 06/11/2023]
Abstract
Geobacter sulfurreducens biofilms have promising applications in renewable energy, pollutant bioremediation, and bioelectronic applications. Genetically manipulating G. sulfurreducens biofilms is an effective strategy to improve the capacity of extracellular electron transfer (EET). Extracellular polysaccharide, a sticky component surrounding microbes, plays an important role in EET. Herein, we constructed a mutant of G. sulfurreducens strain PCA overexpressing the gene GSU1501 (part of the ATP-dependent exporter of the polysaccharide biosynthesis gene operon), designated strain PCA-1501, to increase EET capacity. Experimental results showed that the overexpression of GSU1501 increased extracellular polysaccharide secretion by 25.5%, which promoted the formation of biofilm with higher thickness and viability, as well as the content of extracellular c-type cytochromes. Compared with the control strain, the mutant showed a higher capacity of Fe(III) oxide reduction and current generation (increased by 20.4% and 22.2%, respectively). Interestingly, the overexpression of GSU1501 hindered the pili formation by reducing the transcription level of pilA; a compensatory relationship between extracellular polysaccharide and pili in promoting biofilm formation deserves further investigation. This study provides a feasible method to promote the EET capacity of G. sulfurreducens biofilms, which benefit their bioelectrochemical applications.
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Affiliation(s)
- Zheng Zhuang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
| | - Guiqin Yang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
| | - Qijun Mai
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
| | - Junhui Guo
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
| | - Xing Liu
- College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Li Zhuang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China.
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Ptushenko VV. Electric Cables of Living Cells. II. Bacterial Electron Conductors. BIOCHEMISTRY (MOSCOW) 2020; 85:955-965. [PMID: 33045956 DOI: 10.1134/s0006297920080118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The concept of "electric cables" involved in bioenergetic processes of a living cell was proposed half a century ago [Skulachev, V. P. (1971) Curr. Top. Bioenerg., Elsevier, pp. 127-190]. For many decades, only cell membrane structures have been considered as probable pathways for the electric current, namely, for the transfer of transmembrane electrochemical potential. However, the last ten to fifteen years have brought the discovery of bacterial "electric cables" of a new type. In 2005, "nanowires" conducting electric current over distances of tens of micrometers were discovered in metal- and sulphate-reducing bacteria [Reguera, G. et al. (2005) Nature, 435, pp. 1098-1101]. The next five years have witnessed the discovery of microbial electric currents over centimeter distances [Nielsen, L. P. et al. (2010) Nature, 463, 1071-1074]. This new group of bacteria allowing electric currents to flow over macroscopic distances was later called cable bacteria. Nanowires and conductive structures of cable bacteria serve to solve a special problem of membrane bioenergetics: they connect two redox half-reactions. In other words, unlike membrane "cables", their function is electron transfer in the course of oxidative phosphorylation for the generation of membrane energy rather than of the end-product. The most surprising is the protein nature of these cables (at least of some of them) indicated by recent data, since no protein wires for the long-distance electron transport had been previously known in living systems.
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Affiliation(s)
- V V Ptushenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia. .,Emanuel Institute of Biochemical Physics of the Russian Academy of Sciences, Moscow, 119334, Russia
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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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Wei W, Plymale A, Zhu Z, Ma X, Liu F, Yu XY. In Vivo Molecular Insights into Syntrophic Geobacter Aggregates. Anal Chem 2020; 92:10402-10411. [PMID: 32614167 DOI: 10.1021/acs.analchem.0c00653] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Direct interspecies electron transfer (DIET) has been considered as a novel and highly efficient strategy in both natural anaerobic environments and artificial microbial fuel cells. A syntrophic model consisting of Geobacter metallireducens and Geobacter sulfurreducens was studied in this work. We conducted in vivo molecular mapping of the outer surface of the syntrophic community as the interface of nutrients and energy exchange. System for Analysis at the Liquid Vacuum Interface combined with time-of-flight secondary ion mass spectrometry was employed to capture the molecular distribution of syntrophic Geobacter communities in the living and hydrated state. Principal component analysis with selected peaks revealed that syntrophic Geobacter aggregates were well differentiated from other control samples, including syntrophic planktonic cells, pure cultured planktonic cells, and single population biofilms. Our in vivo imaging indicated that a unique molecular surface was formed. Specifically, aromatic amino acids, phosphatidylethanolamine components, and large water clusters were identified as key components that favored the DIET of syntrophic Geobacter aggregates. Moreover, the molecular changes in depths of the Geobacter aggregates were captured using dynamic depth profiling. Our findings shed new light on the interface components supporting electron transfer in syntrophic communities based on in vivo molecular imaging.
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Affiliation(s)
- Wenchao Wei
- Key Laboratory of Coastal Biology and Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, P. R. China.,Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.,University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Andrew Plymale
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Zihua Zhu
- Environmental and Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Xiang Ma
- Department of Chemistry, Grand View University, Des Moines, Iowa 50316, United States
| | - Fanghua Liu
- Key Laboratory of Coastal Biology and Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, P. R. China
| | - Xiao-Ying Yu
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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Koga R, Matsumoto A, Kouzuma A, Watanabe K. Identification of an extracytoplasmic function sigma factor that facilitates
c
‐type cytochrome maturation and current generation under electrolyte‐flow conditions in
Shewanella oneidensis
MR
‐1. Environ Microbiol 2020; 22:3671-3684. [DOI: 10.1111/1462-2920.15131] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/11/2020] [Accepted: 06/13/2020] [Indexed: 11/27/2022]
Affiliation(s)
- Ryota Koga
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences 1432‐1 Horinouchi, Hachioji Tokyo 192‐0392 Japan
| | - Akiho Matsumoto
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences 1432‐1 Horinouchi, Hachioji Tokyo 192‐0392 Japan
| | - Atsushi Kouzuma
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences 1432‐1 Horinouchi, Hachioji Tokyo 192‐0392 Japan
| | - Kazuya Watanabe
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences 1432‐1 Horinouchi, Hachioji Tokyo 192‐0392 Japan
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Yu HQ. Molecular Insights into Extracellular Polymeric Substances in Activated Sludge. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:7742-7750. [PMID: 32479069 DOI: 10.1021/acs.est.0c00850] [Citation(s) in RCA: 173] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Extracellular polymeric substances (EPS) are known to crucially affect the properties and performance of activated sludge, but the detailed influential mechanisms and the pertinence to specific compositional, structural properties of EPS are still elusive. Such knowledge gaps have severely limited our ability in optimizing biological wastewater treatment processes, for which long-term robust and efficient sludge performance remains one of the main bottlenecks. Here, we overview the new knowledge on the molecular structure of sludge EPS gained over the past few years and discuss the future challenges and opportunities for further advancing EPS study and engineering. The structural and functional features of several macromolecules in sludge EPS and their important structural roles in granular sludge are analyzed in detail. The EPS-pollutant interactions and environment-dependent regulation machinery on EPS production are deciphered. Lastly, the remaining knowledge gaps are identified, and the future research needs that may lead to molecular-level understanding and precise engineering of sludge EPS are highlighted.
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Affiliation(s)
- Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
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Philipp LA, Edel M, Gescher J. Genetic engineering for enhanced productivity in bioelectrochemical systems. ADVANCES IN APPLIED MICROBIOLOGY 2020; 111:1-31. [PMID: 32446410 DOI: 10.1016/bs.aambs.2020.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A shift from petrochemical processes toward a bio-based economy is one of the most advocated developments for a sustainable future. To achieve this will require the biotechnological production of platform chemicals that can be further processed by chemical engineering. Bioelectrochemical systems (BESs) are a novel tool within the biotechnology field. In BESs, microbes serve as biocatalysts for the production of biofuels and value-added compounds, as well as for the production of electricity. Although the general feasibility of bioelectrochemical processes has been demonstrated in recent years, much research has been conducted to develop biocatalysts better suited to meet industrial demands. Initially, mainly natural exoelectrogenic organisms were investigated for their performance in BESs. Driven by possibilities of recent developments in genetic engineering and synthetic biology, the spectrum of microbial catalysts and their versatility (substrate and product range) have expanded significantly. Despite these developments, there is still a tremendous gap between currently achievable space-time yields and current densities on the one hand and the theoretical limits of BESs on the other. It will be necessary to move the performance of the biocatalysts closer to the theoretical possibilities in order to establish viable production routines. This review summarizes the status quo of engineering microbial biocatalysts for anode-applications with high space-time yields. Furthermore, we will address some of the theoretical limitations of these processes exemplarily and discuss which of the present strategies might be combined to achieve highly synergistic effects and, thus, meet industrial demands.
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Affiliation(s)
- Laura-Alina Philipp
- Karlsruhe Institute of Technology, Institute for Applied Biosciences-Department of Applied Biology, Karlsruhe, Germany
| | - Miriam Edel
- Karlsruhe Institute of Technology, Institute for Applied Biosciences-Department of Applied Biology, Karlsruhe, Germany
| | - Johannes Gescher
- Karlsruhe Institute of Technology, Institute for Applied Biosciences-Department of Applied Biology, Karlsruhe, Germany; Karlsruhe Institute of Technology, Institute for Biological Interfaces, Eggenstein-Leopoldshafen, Germany.
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Wang B, Liu W, Zhang Y, Wang A. Bioenergy recovery from wastewater accelerated by solar power: Intermittent electro-driving regulation and capacitive storage in biomass. WATER RESEARCH 2020; 175:115696. [PMID: 32179273 DOI: 10.1016/j.watres.2020.115696] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 06/10/2023]
Abstract
Electroactive microorganisms (EAMs) can act as pseudocapacitor to store energy and discharge electrons on need, while electromethanogens acting as receptor are able to utilize electrons, protons and carbon dioxide for methanization. However, external energy is required to overcome thermodynamical barriers for electromethanogenesis. Herein, electro-driving power by solar light was established to accelerate conversion of waste organics to bioenergy. The intermittent power supply modes were elucidated for favourable performances (e.g., current density, methane production rate, energy recovery efficiencies and economic evaluation), compared with the control driven by continuous applied voltage. It was found that natural intermittent solar-powered mode was more beneficial for microorganisms involved in electron transfer and energy recovery than manual sharp on-off mode. Electrochemistry analysis unrevealed that a higher redox current and lower resistance were exhibited under the solar-powered mode. A high charge storage capacity and electron mobility were found through cytochrome c content and live cells ratio in the solar-power assisted bioreactor. The intermittent power driving modes can regulate electron transfer proteins with capacitive storage behavior in biomass, which helps to understand the responses of functional communities on the stress of intermittent electric field. These findings indicate a promising perspective of microbial biotechnology driven by solar power to boost bioenergy recovery from waste/wastewater.
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Affiliation(s)
- Bo Wang
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Department of Environmental Engineering, Technical University of Denmark, DK, 2800, Lyngby, Denmark; Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100049, China; Sino-Danish Center for Education and Research, Beijing, 100190, China
| | - Wenzong Liu
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
| | - Yifeng Zhang
- Department of Environmental Engineering, Technical University of Denmark, DK, 2800, Lyngby, Denmark
| | - Aijie Wang
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
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Global transcriptional analysis of Geobacter sulfurreducens under palladium reducing conditions reveals new key cytochromes involved. Appl Microbiol Biotechnol 2020; 104:4059-4069. [DOI: 10.1007/s00253-020-10502-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 02/19/2020] [Accepted: 02/26/2020] [Indexed: 01/15/2023]
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Effect of electrode spacing on electron transfer and conductivity of Geobacter sulfurreducens biofilms. Bioelectrochemistry 2020; 131:107395. [DOI: 10.1016/j.bioelechem.2019.107395] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 09/12/2019] [Accepted: 09/13/2019] [Indexed: 12/19/2022]
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Microalgae as a biocathode and feedstock in anode chamber for a self-sustainable microbial fuel cell technology: A review. SOUTH AFRICAN JOURNAL OF CHEMICAL ENGINEERING 2020. [DOI: 10.1016/j.sajce.2019.10.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] Open
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49
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Liu X, Ye Y, Xiao K, Rensing C, Zhou S. Molecular evidence for the adaptive evolution of Geobacter sulfurreducens to perform dissimilatory iron reduction in natural environments. Mol Microbiol 2019; 113:783-793. [PMID: 31872462 DOI: 10.1111/mmi.14443] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 12/17/2019] [Accepted: 12/19/2019] [Indexed: 02/05/2023]
Abstract
The electrically conductive pili (e-pili) of Geobacter species enable extracellular electron transfer to insoluble metallic minerals, electrodes and other microbial species, which confers biogeochemical significance and global prevalence on Geobacter in diverse anaerobic environments. E-pili are constructed by truncated PilA which is considered to have evolved from full-length pilin by gene fission under positive evolutionary selection. However, this hypothesis is based on phylogenetic analysis and has not yet been experimentally confirmed. Here, we reconstructed an ancestral strain of G. sulfurreducens (designated COMB) carrying full-length PilA by combining genes GSU1496 and GSU1497. The results demonstrated that strain COMB expressed and assembled the full-length fused PilA and exhibited an outer membrane c-type cytochrome profile similar to the wild-type strain. Surprisingly, the generated COMB-pili were also conductive, indicating the evolution of truncated PilA did not occur for conductivity. Moreover, strain COMB minimally reduced Fe(III) oxides but maintained its ability to respire electrodes, demonstrating the truncation of pilin enables iron respiration. This study provides the first experimental evidence that the truncation of pilin in Geobacter species confers adaption to Fe(III)-mineral-mediated selective pressures, and suggests an evolutionary event during which the separation of the GSU1497 gene helped Geobacter survive and thrive in natural environments.
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Affiliation(s)
- Xing Liu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yin Ye
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ke Xiao
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing, China
| | - Christopher Rensing
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
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Liu X, Zhuo S, Jing X, Yuan Y, Rensing C, Zhou S. Flagella act as Geobacter biofilm scaffolds to stabilize biofilm and facilitate extracellular electron transfer. Biosens Bioelectron 2019; 146:111748. [DOI: 10.1016/j.bios.2019.111748] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/22/2019] [Accepted: 09/30/2019] [Indexed: 11/24/2022]
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