Revealing cellular (poly)sulphide storage in electrochemically active sulphide oxidising bacteria using rotating disc electrodes

Rikke Linssen, Sanne de Smit, Katharina Röhring (neé Neubert), Falk Harnisch, Annemiek ter Heijne*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Sulphide oxidising bacteria (SOB) have the potential to be used for bioelectrochemical removal, i.e. oxidation, of sulphide from waste streams. In anaerobic conditions, SOB are able to spatially separate sulphide removal and terminal electron transfer to an electrode and act as a sulphide shuttle. However, it is not fully understood how SOB anaerobically remove sulphide and store charge equivalents, and where in this process sulphur is formed. Therefore, the redox behaviour of sulphide shuttling SOB was investigated at haloalkaline conditions using a glassy carbon rotating disc electrode (RDE) and cyclic voltammetry. Voltammograms of SOB in the absence and presence of sulphide were compared to voltammograms of abiotic sulphur species solutions. Polysulphide and sulphide showed different redox behaviour, with distinct potentials for oxidation of > −0.3 V (vs. Ag/AgCl) for polysulphide and > −0.1 V for sulphide. Comparing biotic to abiotic experiments lead to the hypothesis that SOB formed polysulphides during anaerobic sulphide removal, which stayed sorbed to the cells. With this study, further steps were taken in elucidating the mechanisms of sulphide shuttling by SOB.

Original languageEnglish
Article number108710
JournalBioelectrochemistry
Volume158
DOIs
Publication statusPublished - Aug 2024

Keywords

  • Biodesulphurisation
  • Microbial charge storage
  • Microbial electrochemical technology
  • Rotating disc electrode
  • Sulphide oxidising bacteria

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