Isolation and Characterization of a Novel Electrogenic Bacterium, Dietzia sp. RNV-4

PLoS One. 2017 Feb 13;12(2):e0169955. doi: 10.1371/journal.pone.0169955. eCollection 2017.

Abstract

Electrogenic bacteria are organisms that can transfer electrons to extracellular electron acceptors and have the potential to be used in devices such as bioelectrochemical systems (BES). In this study, Dietzia sp. RNV-4 bacterium has been isolated and identified based on its biochemical, physiological and morphological characteristics, as well as by its 16S rRNA sequence analysis. Furthermore, the current density production and electron transfer mechanisms were investigated using bioelectrochemical methods. The chronoamperometric data showed that the biofilm of Dietzia sp. RNV-4 grew as the current increased with time, reaching a maximum of 176.6 ± 66.1 mA/m2 at the end of the experiment (7 d); this highly suggests that the current was generated by the biofilm. The main electron transfer mechanism, indicated by the cyclic voltammograms, was due to secreted redox mediators. By high performance liquid chromatography, canthaxanthin was identified as the main compound involved in charge transfer between the bacteria and the solid electrodes. Dietzia sp. RNV-4 was used as biological material in a microbial fuel cell (MFC) and the current density production was 299.4 ± 40.2 mA/m2. This is the first time that Dietzia sp. RNV-4 has been electrochemically characterized and identified as a new electrogenic strain.

MeSH terms

  • Actinobacteria / genetics
  • Actinobacteria / isolation & purification*
  • Actinobacteria / metabolism*
  • Bioelectric Energy Sources / microbiology*
  • Biofilms
  • Canthaxanthin / metabolism
  • Electrochemical Techniques / methods*
  • Electron Transport
  • Electrons
  • Microscopy, Confocal
  • Microscopy, Electron, Scanning
  • Oxidation-Reduction
  • Phylogeny
  • RNA, Ribosomal, 16S / genetics

Substances

  • RNA, Ribosomal, 16S
  • Canthaxanthin

Grants and funding

This work was supported by the Consejo Nacional de Investigaciones Científicas y Técnicas (PIP 112-200801-00502), and The Agencia Nacional de Promoción Científica y Tecnológica (Préstamo BID, PICT 2013-0033 and PICT 2014-0402). Funding was received by EC. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.