Role of Nitrogenase and Ferredoxin in the Mechanism of Bioelectrocatalytic Nitrogen Fixation by the Cyanobacteria Anabaena variabilis SA-1 Mutant Immobilized on Indium Tin Oxide (ITO) Electrodes

Knoche, Krysti L.; Aoyama, Erika; Hasan, Kamrul; Minteer, Shelley D.

doi:10.1016/j.electacta.2017.02.148

Cited by 26 publications

(19 citation statements)

References 35 publications

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“…Relative to other bioelectrochemical technologies at ambient conditions, the MEC NH 4 + generation rates are quite comparable. Normalized to the anode surface area, the MEC rates increased from 1.3 × 10 −12 mol of NH 4 + s −1 cm −2 at E AP = 0.7 V up to 5.2 × 10 −12 mol of NH 4 + s −1 cm −2 at E AP = 1.0 V. Knoche et al, 10 in the only study to date that reports bioelectrochemical NH 4 + excretion, immobilized cells of Anabaena variabilis SA-1 onto indium tin oxide electrodes and applied cyclic voltammetry, producing up to 4.7 μM NH 4 + at a rate of 2.6 × 10 −12 mol s −1 cm −2 . 10 Milton et al 5 used a fuel cell with electrode-immobilized nitrogenase and hydrogenase enzymes instead of whole-cell microorganisms.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Normalized to the anode surface area, the MEC rates increased from 1.3 × 10 −12 mol of NH 4 + s −1 cm −2 at E AP = 0.7 V up to 5.2 × 10 −12 mol of NH 4 + s −1 cm −2 at E AP = 1.0 V. Knoche et al, 10 in the only study to date that reports bioelectrochemical NH 4 + excretion, immobilized cells of Anabaena variabilis SA-1 onto indium tin oxide electrodes and applied cyclic voltammetry, producing up to 4.7 μM NH 4 + at a rate of 2.6 × 10 −12 mol s −1 cm −2 . 10 Milton et al 5 used a fuel cell with electrode-immobilized nitrogenase and hydrogenase enzymes instead of whole-cell microorganisms. Their system generated 2.3 × 10 −11 mol of NH 4 + s −1 cm −2 after applying 60 mC of charge over 2 h. However, an electron mediator (methyl viologen) was required to shuttle electrons to/from both enzymes.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Research in electromicrobiology has shown that electrically active microorganisms, many of which are known diazotrophs, are highly responsive to electrical driving forces. 10 In anaerobic microbial electrolysis cells (MECs), applied voltage drives the conversion of organic material into electrical current by anode respiring microorganisms (exoelectrogens), resulting in the production of energy-rich gases, for example, H 2 and CH 4 . 11 Community analyses of anode biofilms have revealed that Geobacter species predominate in these systems.…”

Section: ■ Introductionmentioning

confidence: 99%

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Nitrogen Gas Fixation and Conversion to Ammonium Using Microbial Electrolysis Cells

Ortiz-Medina

Grunden

Hyman

et al. 2019

ACS Sustainable Chem. Eng.

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Ammonia (NH3) is an important industrial chemical that is produced using the energy- and carbon-intensive Haber-Bosch process. Recovering NH3 from microorganisms that fix nitrogen gas (N2) may provide a sustainable alternative because their specialized nitrogenase enzymes can reduce N2 to ammonium (NH4 +) without the need for high temperature and pressure. This study explored the possibility of converting N2 into NH4 + using anaerobic, single-chamber microbial electrolysis cells (MECs). N2 fixation rates [based on an acetylene gas (C2H2) to ethylene gas (C2H4) conversion assay] of a microbial consortium increased significantly when the applied voltage between the anode and cathode increased from 0.7 to 1.0 V and reached a maximum of ∼40 nmol of C2H4 min–1 mg protein–1, which is comparable to model aerobic N2-fixing bacteria. The presence of NH4 +, which can inhibit the activity of the nitrogenase enzyme, did not significantly reduce N2 fixation rates. Upon addition of methionine sulfoximine, an NH4 + uptake inhibitor, NH4 + was recovered at rates approaching 5.2 × 10–12 mol of NH4 + s–1 cm–2 (normalized to the anode surface area). Relative to the electrical energy consumed, the normalized energy demand [MJ mol–1 (NH4 +)] was negative because of the energy-rich methane gas recovered in the MEC. Including the substrate energy resulted in total energy demands as low as 24 MJ mol–1. Community analysis results of the anode biofilms revealed that Geobacter species predominated in both the presence and absence of NH4 +, suggesting that they played a key role in current generation and N2 fixation. This study shows that MECs may provide a new route for generating NH4 +.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Nitrogen Gas Fixation and Conversion to Ammonium Using Microbial Electrolysis Cells

Ortiz-Medina

Grunden

Hyman

et al. 2019

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

show abstract

“…Rather than relying on purified biological components, one alternative option is to use electro‐microbial biocatalysis . To this end, there are a growing number of reports using bacteria immobilised on electrodes to produce ammonia from dinitrogen . One particularly promising example has been reported by Nocera and co‐workers, whereby H 2 is used to grow X anthobacter autrophicus , which is capable of fixing CO 2 and N 2 .…”

Section: Obstacles and Opportunities For Using Nitrogenase For Energymentioning

confidence: 99%

Insights into Nitrogenase Bioelectrocatalysis for Green Ammonia Production

et al. 2020

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There is a growing interest in using ammonia as a liquid carrier of hydrogen for energy applications. Currently, ammonia is produced industrially by the Haber-Bosch process, which requires high temperature and high pressure. In contrast, bacteria have naturally evolved an enzyme known as nitrogenase, that is capable of producing ammonia and hydrogen at ambient temperature and pressure. Therefore, nitrogenases are attractive as a potentially more efficient means to produce ammonia via harnessing the unique properties of this enzyme. In recent years, exciting progress has been made in bioelectrocatalysis using nitrogenases to produce ammonia. Here, the prospects for developing biological ammonia production are outlined, key advances in bioelectrocatalysis by nitrogenases are highlighted, and possible solutions to the obstacles faced in realising this goal are discussed.

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“…Typical environmental electroactive bacteria exhibit lower redox potential than those of cyanobacteria in CV (e. g. Gram-negative iron reducing bacteria: about À 0.2 -+ 0.2 V vs SHE), [20] thus, redox signals of cyanobacteria are not likely masked by other bacteria. Given that a previous report also showed another cyanobacterium, Anabaena variabilis, exhibits a redox peak at around + 0.74 V vs. SHE, [21] the appearance of redox peaks in the + 0.60 -+ 0.75 V vs. SHE region (at around pH 8) may be used as an indicator of the onset of a cyanobacterial bloom.…”

mentioning

confidence: 96%

Synechococcus and Other Bloom‐Forming Cyanobacteria Exhibit Unique Redox Signatures

et al. 2020

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Cyanobacteria form dense blooms that impair water quality. Although the impact of blooms on water quality largely differs depending on the species of cyanobacteria, it is challenging to distinguish cyanobacterial species with conventional sensors due to their similar physicochemical properties. Here, we conducted cyclic voltammetry to three major bloom‐forming cyanobacteria, Synechococcus sp., Microcystis aeruginosa, and Anabaena circinalis without addition of redox active compounds nor chemical modifications of the working electrode. These cyanobacteria exhibited redox peaks with distinct potentials from each other, in the range of +0.60 – +0.75 V vs SHE. Because these redox potentials hardly overlap with those of other environmental electroactive bacteria, those redox peaks may be used as indicators of the onset of a cyanobacterial bloom. Given that the photo‐responsive current correlated with the cell density of Synechococcus sp., electrochemical measurement would be a promising technique for a novel cyanobacterial quantification sensor, with in‐built ability to identify cyanobacterial species.

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Role of Nitrogenase and Ferredoxin in the Mechanism of Bioelectrocatalytic Nitrogen Fixation by the Cyanobacteria Anabaena variabilis SA-1 Mutant Immobilized on Indium Tin Oxide (ITO) Electrodes

Cited by 26 publications

References 35 publications

Nitrogen Gas Fixation and Conversion to Ammonium Using Microbial Electrolysis Cells

Nitrogen Gas Fixation and Conversion to Ammonium Using Microbial Electrolysis Cells

Insights into Nitrogenase Bioelectrocatalysis for Green Ammonia Production

Synechococcus and Other Bloom‐Forming Cyanobacteria Exhibit Unique Redox Signatures

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