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Front. Microbiol. | doi: 10.3389/fmicb.2019.00582

Reducing conditions favor magnetosome production in Magnetospirillum magneticum AMB-1

  • 1Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Germany
  • 2CEA Cadarache, France

MMagnetotactic bacteria are a heterogeneous group of Gram-negative prokaryotes, which all produce special magnetic organelles called magnetosomes. The magnetosome consists of a magnetic nanoparticle, either magnetite (Fe3O4) or greigite (Fe3S4), embedded in a membrane, which renders the systems colloidaly stable, a desirable property for biotechnological applications. Although these bacteria are able to regulate the formation of magnetosomes through a biologically-controlled mechanism, the environment in general and the physico–chemical conditions surrounding the cells in particular also influence biomineralization. This work thus aims at understanding how such external conditions, in particular the extracellular oxidation reduction potential, influence magnetite formation in the strain Magnetospirillum magneticum AMB-1. Controlled cultivation of the microorganisms was performed at different redox potential in a bioreactor and the formation of magnetosomes was assessed by microscopic and spectroscopic techniques. Our results show that the formation of magnetosomes is inhibited at the highest potential tested (0 mV), whereas biomineralization is facilitated under reduced conditions (- 500 mV). This result improves the understanding of the biomineralization process in MTB and provides useful information in sight of a large scale production of magnetosomes for different applications.

Keywords: Redox potential - Eh, magnetotactic bacteria, Iron, Magnetite (Fe 3O 4) nanoparticles, Biomineralization

Received: 27 Jul 2018; Accepted: 07 Mar 2019.

Edited by:

Concepcion Jimenez-Lopez, University of Granada, Spain

Reviewed by:

Aihua Liu, Qingdao University, China
Alberto Perez-Huerta, University of Alabama, United States  

Copyright: © 2019 Faivre, Olszewska-WIddrat, Schiro and Reichel. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Damien Faivre, Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Potsdam, 14476, Brandenburg, Germany, damien.faivre@cea.fr