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Fattahi N, Reed J, Heronemus E, Fernando P, Hansen R, Parameswaran P. Polyethylene glycol hydrogel coatings for protection of electroactive bacteria against chemical shocks. Bioelectrochemistry 2024; 156:108595. [PMID: 37976771 DOI: 10.1016/j.bioelechem.2023.108595] [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: 07/18/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 11/19/2023]
Abstract
Loss of bioelectrochemical activity in low resource environments or from chemical toxin exposure is a significant limitation in microbial electrochemical cells (MxCs), necessitating the development of materials that can stabilize and protect electroactive biofilms. Here, polyethylene glycol (PEG) hydrogels were designed as protective coatings over anodic biofilms, and the effect of the hydrogel coatings on biofilm viability under oligotrophic conditions and ammonia-N (NH4+-N) shocks was investigated. Hydrogel deposition occurred through polymerization of PEG divinyl sulfone and PEG tetrathiol precursor molecules, generating crosslinked PEG coatings with long-term hydrolytic stability between pH values of 3 and 10. Simultaneous monitoring of coated and uncoated electrodes co-located within the same MxC anode chamber confirmed that the hydrogel did not compromise biofilm viability, while the coated anode sustained nearly a 4 × higher current density (0.44 A/m2) compared to the uncoated anode (0.12 A/m2) under oligotrophic conditions. Chemical interactions between NH4+-N and PEG hydrogels revealed that the hydrogels provided a diffusive barrier to NH4+-N transport. This enabled PEG-coated biofilms to generate higher current densities during NH4+-N shocks and faster recovery afterwards. These results indicate that PEG-based coatings can expand the non-ideal chemical environments that electroactive biofilms can reliably operate in.
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Affiliation(s)
- Niloufar Fattahi
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS 66506, USA
| | - Jeffrey Reed
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS 66506, USA
| | - Evan Heronemus
- Department of Civil Engineering, Kansas State University, Manhattan, KS 66506, USA
| | - Priyasha Fernando
- Department of Civil Engineering, Kansas State University, Manhattan, KS 66506, USA
| | - Ryan Hansen
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS 66506, USA.
| | - Prathap Parameswaran
- Department of Civil Engineering, Kansas State University, Manhattan, KS 66506, USA.
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Veerubhotla R, Marzocchi U. Examining the resistance and resilience of anode-respiring Shewanella oneidensis biohybrid using microsensors. CHEMOSPHERE 2024; 350:141109. [PMID: 38176592 DOI: 10.1016/j.chemosphere.2024.141109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 12/09/2023] [Accepted: 01/01/2024] [Indexed: 01/06/2024]
Abstract
Immobilizing electro-active microbes within polymer matrices (thereby forming biohybrids) is a promising approach to accelerate microbial attachment to electrodes and increase the biofilm robustness. However, little is known on the fine scale chemical environment that develops within the electro-active biohybrids. Herein, we develop a biohybrid by immobilizing a culture of Shewanella oneidensis MR1 in agar matrix on the surface of a graphite electrode poised at +0.25 V. The resulting bioanode (3-6 mm thick) was grown under anoxic conditions and produced a steady current of 40 μA. Oxygen and pH distribution within the biohybrid were characterized in-situ using microsensors. As Shewanella is a facultative aerobe, it will halt the current production in the presence of oxygen. Thus, in addition, we investigated the alteration of the microenvironment during and after aeration of the medium to evaluate the oxygen tolerance of the system. During aeration, oxygen was effectively consumed in the top layers of the biofilm, leaving a 400-900 μm thick anoxic zone on the anode surface, that sustained >60% of the initial current. Current production recovered to pre-oxic condition within 5 h after the aeration was stopped, showing that immobilization can promote both high resistance and resilience of the system. Despite the absence of strong buffering conditions, pH profiles indicated a maximum drop of 0.2 units across the biohybrid. Characterizing the chemical microenvironment helps to elucidate the mechanistic functioning of artificial biofilms and hold a great potential for the designing of future, more effective biohybrid electrodes.
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Affiliation(s)
- Ramya Veerubhotla
- Aarhus University Center for Water Technology WATEC, Department of Biology, Aarhus University, Denmark.
| | - Ugo Marzocchi
- Aarhus University Center for Water Technology WATEC, Department of Biology, Aarhus University, Denmark; Center for Electromicrobiology CEM, Department of Biology, Aarhus University, Denmark
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Qi X, Wang S, Jiang Y, Liu P, Li Q, Hao W, Han J, Zhou Y, Huang X, Liang P. Artificial electrochemically active biofilm for improved sensing performance and quickly devising of water quality early warning biosensors. WATER RESEARCH 2021; 198:117164. [PMID: 33915405 DOI: 10.1016/j.watres.2021.117164] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/29/2021] [Accepted: 04/14/2021] [Indexed: 06/12/2023]
Abstract
A major challenge for devising an electrochemically active biofilm (EAB)-based biosensor for real-time water quality early-warning is the formation of EAB that requires several days to weeks. Besides the onerous and time-consuming preparation process, the naturally formed EABs are intensively concerned as they can hardly deliver repeatable electrical signals even at identical experimental conditions. To address these concerns, this study employed sodium alginate as immobilization agent to encapsulate Shewanella oneidensis MR-1 and prepared EAB for devising a biosensor in a short period of less than 1 h. The artificial EAB were found capable of delivering highly consistent electrical signals with each other when fed with the same samples. Morphology and bioelectrochemical properties of the artificial EAB were investigated to provide interpretations for these findings. Different concentrations of bacteria and alginate in forming the EAB were investigated for their effects on the biosensor's sensitivity. Results suggested that lower concentration of bacteria would be beneficial until it increased to 0.06 (OD660). Concentration of sodium alginate affected the sensitivity as well and 1% was found an optimum amount to serve in the formation of EAB. A long-term operation of the biosensor with artificial EAB for 110 h was performed. Clear warning signals for incoming toxicants were observed over random signal fluctuations. All results suggested that the artificial EAB electrode would support a rapid devised and highly sensitivity biosensor.
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Affiliation(s)
- Xiang Qi
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Shuyi Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Yong Jiang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, PR China
| | - Panpan Liu
- School of Ecology and Environment, Zhengzhou University, Zhengzhou 450001, P.R. China
| | - Qingcheng Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Wen Hao
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Jinbin Han
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Yuexi Zhou
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Xia Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Peng Liang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China.
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Heydorn RL, Engel C, Krull R, Dohnt K. Strategies for the Targeted Improvement of Anodic Electron Transfer in Microbial Fuel Cells. CHEMBIOENG REVIEWS 2019. [DOI: 10.1002/cben.201900023] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Raymond Leopold Heydorn
- Technische Universität BraunschweigInstitute of Biochemical Engineering, Braunschweig Integrated Centre of Systems Biology Rebenring 56 38106 Braunschweig Germany
| | - Christina Engel
- Technische Universität BraunschweigInstitute of Biochemical Engineering, Braunschweig Integrated Centre of Systems Biology Rebenring 56 38106 Braunschweig Germany
| | - Rainer Krull
- Technische Universität BraunschweigInstitute of Biochemical Engineering, Braunschweig Integrated Centre of Systems Biology Rebenring 56 38106 Braunschweig Germany
| | - Katrin Dohnt
- Technische Universität BraunschweigInstitute of Biochemical Engineering, Braunschweig Integrated Centre of Systems Biology Rebenring 56 38106 Braunschweig Germany
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Strategies for improving the electroactivity and specific metabolic functionality of microorganisms for various microbial electrochemical technologies. Biotechnol Adv 2019; 39:107468. [PMID: 31707076 DOI: 10.1016/j.biotechadv.2019.107468] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 11/02/2019] [Accepted: 11/04/2019] [Indexed: 01/31/2023]
Abstract
Electroactive microorganisms, which possess extracellular electron transfer (EET) capabilities, are the basis of microbial electrochemical technologies (METs) such as microbial fuel and electrolysis cells. These are considered for several applications ranging from the energy-efficient treatment of waste streams to the production of value-added chemicals and fuels, bioremediation, and biosensing. Various aspects related to the microorganisms, electrodes, separators, reactor design, and operational or process parameters influence the overall functioning of METs. The most fundamental and critical performance-determining factor is, however, the microorganism-electrode interactions. Modification of the electrode surfaces and microorganisms for optimizing their interactions has therefore been the major MET research focus area over the last decade. In the case of microorganisms, primarily their EET mechanisms and efficiencies along with the biofilm formation capabilities, collectively considered as microbial electroactivity, affect their interactions with the electrodes. In addition to electroactivity, the specific metabolic or biochemical functionality of microorganisms is equally crucial to the target MET application. In this article, we present the major strategies that are used to enhance the electroactivity and specific functionality of microorganisms pertaining to both anodic and cathodic processes of METs. These include simple physical methods based on the use of heat and magnetic field along with chemical, electrochemical, and growth media amendment approaches to the complex procedure-based microbial bioaugmentation, co-culture, and cell immobilization or entrapment, and advanced toolkit-based biofilm engineering, genetic modifications, and synthetic biology strategies. We further discuss the applicability and limitations of these strategies and possible future research directions for advancing the highly promising microbial electrochemistry-driven biotechnology.
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Heydorn RL, Engel C, Krull R, Dohnt K. Strategien zur gezielten Verbesserung des anodenseitigen Elektronentransfers in mikrobiellen Brennstoffzellen. CHEM-ING-TECH 2019. [DOI: 10.1002/cite.201800214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Raymond Leopold Heydorn
- Technische Universität BraunschweigInstitut für Bioverfahrenstechnik, Braunschweiger Zentrum für Systembiologie Rebenring 56 38106 Braunschweig Deutschland
| | - Christina Engel
- Technische Universität BraunschweigInstitut für Bioverfahrenstechnik, Braunschweiger Zentrum für Systembiologie Rebenring 56 38106 Braunschweig Deutschland
| | - Rainer Krull
- Technische Universität BraunschweigInstitut für Bioverfahrenstechnik, Braunschweiger Zentrum für Systembiologie Rebenring 56 38106 Braunschweig Deutschland
| | - Katrin Dohnt
- Technische Universität BraunschweigInstitut für Bioverfahrenstechnik, Braunschweiger Zentrum für Systembiologie Rebenring 56 38106 Braunschweig Deutschland
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Kaushik S, Goswami P. Bacterial Membrane Depolarization-Linked Fuel Cell Potential Burst as Signal for Selective Detection of Alcohol. ACS APPLIED MATERIALS & INTERFACES 2018; 10:18630-18640. [PMID: 29756453 DOI: 10.1021/acsami.8b01838] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The biosensing application of microbial fuel cell (MFC) is hampered by its long response time, poor selectivity, and technical difficulty in developing portable devices. Herein, a novel signal form for rapid detection of ethanol was generated in a photosynthetic MFC (PMFC). First, a dual chambered (100 mL each) PMFC was fabricated by using cyanobacteria-based anode and abiotic cathode, and its performance was examined for detection of alcohols. A graphene-based nanobiocomposite matrix was layered over graphite anode to support cyanobacterial biofilm growth and to facilitate electron transfer. Injection of alcohols into the anodic chamber caused a transient potential burst of the PMFC within 60 s (load 1000 Ω), and the magnitude of potential could be correlated to the ethanol concentrations in the range 0.001-20% with a limit of detection (LOD) of 0.13% ( R2 = 0.96). The device exhibited higher selectivity toward ethanol than methanol as discerned from the corresponding cell-alcohol interaction constant ( Ki) of 780 and 1250 mM. The concept was then translated to a paper-based PMFC (p-PMFC) (size ∼20 cm2) wherein, the cells were merely immobilized over the anode. The device with a shelf life of ∼3 months detected ethanol within 10 s with a dynamic range of 0.005-10% and LOD of 0.02% ( R2 = 0.99). The fast response time was attributed to the higher wettability of ethanol on the immobilized cell surface as validated by the contact angle data. Alcohols degraded the cell membrane on the order of ethanol > methanol, enhanced the redox current of the membrane-bound electron carrier proteins, and pushed the anodic band gap toward more negative value. The consequence was the potential burst, the magnitude of which was correlated to the ethanol concentrations. This novel approach has a great application potential for selective, sensitive, rapid, and portable detection of ethanol.
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