Artificial, Photoinduced Activation of Nitrogenase Using Directed and Mediated Electron Transfer Processes

Nitrogenase, a bacteria-based enzyme, is the sole enzyme that is able to generate ammonia by atmospheric nitrogen fixation. Thus, improved understanding of its utilization and developing methods to artificially activate it may contribute to basic research, as well as to the design of future artifici...

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Main Authors: Matan M. Meirovich, Oren Bachar, Omer Yehezkeli
Format: Article
Language:English
Published: MDPI AG 2020-08-01
Series:Catalysts
Subjects:
Online Access:https://www.mdpi.com/2073-4344/10/9/979
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author Matan M. Meirovich
Oren Bachar
Omer Yehezkeli
author_facet Matan M. Meirovich
Oren Bachar
Omer Yehezkeli
author_sort Matan M. Meirovich
collection DOAJ
description Nitrogenase, a bacteria-based enzyme, is the sole enzyme that is able to generate ammonia by atmospheric nitrogen fixation. Thus, improved understanding of its utilization and developing methods to artificially activate it may contribute to basic research, as well as to the design of future artificial systems. Here, we present methods to artificially activate nitrogenase using photoinduced reactions. Two nitrogenase variants originating from <i>Azotobacter vinelandii</i> were examined using photoactivated CdS nanoparticles (NPs) capped with thioglycolic acid (TGA) or 2-mercaptoethanol (ME) ligands. The effect of methyl viologen (MV) as a redox mediator of hydrogen and ammonia generation was tested and analyzed. We further determined the NPs conductive band edges and their effect on the nitrogenase photoactivation. The nano-biohybrid systems comprising CdS NPs and nitrogenase were further imaged by transmission electron microscopy, visualizing their formation for the first time. Our results show that the ME-capped CdS NPs–nitrogenase enzyme biohybrid system with added MV as a redox mediator leads to a five-fold increase in the production of ammonia compared with the non-mediated biohybrid system; nevertheless, it stills lag behind the natural process rate. On the contrary, a maximal hydrogen generation amount was achieved by the αL158C MoFe-P and the ME-capped CdS NPs.
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spelling doaj.art-41cc893be228409b94c9f43eefffe5ef2023-11-20T11:58:41ZengMDPI AGCatalysts2073-43442020-08-0110997910.3390/catal10090979Artificial, Photoinduced Activation of Nitrogenase Using Directed and Mediated Electron Transfer ProcessesMatan M. Meirovich0Oren Bachar1Omer Yehezkeli2The Laboratory of Nano-Bio Interfaces, Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, 3200000 Haifa, IsraelThe Laboratory of Nano-Bio Interfaces, Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, 3200000 Haifa, IsraelThe Laboratory of Nano-Bio Interfaces, Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, 3200000 Haifa, IsraelNitrogenase, a bacteria-based enzyme, is the sole enzyme that is able to generate ammonia by atmospheric nitrogen fixation. Thus, improved understanding of its utilization and developing methods to artificially activate it may contribute to basic research, as well as to the design of future artificial systems. Here, we present methods to artificially activate nitrogenase using photoinduced reactions. Two nitrogenase variants originating from <i>Azotobacter vinelandii</i> were examined using photoactivated CdS nanoparticles (NPs) capped with thioglycolic acid (TGA) or 2-mercaptoethanol (ME) ligands. The effect of methyl viologen (MV) as a redox mediator of hydrogen and ammonia generation was tested and analyzed. We further determined the NPs conductive band edges and their effect on the nitrogenase photoactivation. The nano-biohybrid systems comprising CdS NPs and nitrogenase were further imaged by transmission electron microscopy, visualizing their formation for the first time. Our results show that the ME-capped CdS NPs–nitrogenase enzyme biohybrid system with added MV as a redox mediator leads to a five-fold increase in the production of ammonia compared with the non-mediated biohybrid system; nevertheless, it stills lag behind the natural process rate. On the contrary, a maximal hydrogen generation amount was achieved by the αL158C MoFe-P and the ME-capped CdS NPs.https://www.mdpi.com/2073-4344/10/9/979nano-bio hybridnitrogenasephotocatalysisCdS nanoparticlesredox mediatormethyl viologen
spellingShingle Matan M. Meirovich
Oren Bachar
Omer Yehezkeli
Artificial, Photoinduced Activation of Nitrogenase Using Directed and Mediated Electron Transfer Processes
Catalysts
nano-bio hybrid
nitrogenase
photocatalysis
CdS nanoparticles
redox mediator
methyl viologen
title Artificial, Photoinduced Activation of Nitrogenase Using Directed and Mediated Electron Transfer Processes
title_full Artificial, Photoinduced Activation of Nitrogenase Using Directed and Mediated Electron Transfer Processes
title_fullStr Artificial, Photoinduced Activation of Nitrogenase Using Directed and Mediated Electron Transfer Processes
title_full_unstemmed Artificial, Photoinduced Activation of Nitrogenase Using Directed and Mediated Electron Transfer Processes
title_short Artificial, Photoinduced Activation of Nitrogenase Using Directed and Mediated Electron Transfer Processes
title_sort artificial photoinduced activation of nitrogenase using directed and mediated electron transfer processes
topic nano-bio hybrid
nitrogenase
photocatalysis
CdS nanoparticles
redox mediator
methyl viologen
url https://www.mdpi.com/2073-4344/10/9/979
work_keys_str_mv AT matanmmeirovich artificialphotoinducedactivationofnitrogenaseusingdirectedandmediatedelectrontransferprocesses
AT orenbachar artificialphotoinducedactivationofnitrogenaseusingdirectedandmediatedelectrontransferprocesses
AT omeryehezkeli artificialphotoinducedactivationofnitrogenaseusingdirectedandmediatedelectrontransferprocesses