Bioelectroanalytical Detection of Lactic Acid Bacteria

Evelina Jing Ying Han, Lola Gonzalez Olias, Stefan Wuertz, Jamie Hinks

Research output: Contribution to journalArticlepeer-review

Abstract

Lactic acid bacteria (LAB) are an industrial important group of organisms that are notable for their inability to respire without growth supplements. Recently described bioelectroanalytical detectors that can specifically detect and enumerate microorganisms depend on a phenomenon known as extracellular electron transport (EET) for effective detection. EET is often described as a type of microbial respiration, which logically excludes LAB from such a detection platform. However, members of the LAB have recently been described as electroactive with the ability to carry out EET, providing a timely impetus to revisit the utility of bioelectroanalytical detectors in LAB detection. Here, we show that an LAB, Enterococcus faecalis, is easily detected bioelectroanalytically using the defined substrate resorufin-β-D-galactopyranoside. Detection is rapid, ranging from 34 to 235 min for inoculum sizes between 107 and 104 CFU mL−1, respectively. We show that, although the signal achieved by Enterococcus faecalis is comparable to systems that rely on the respiratory EET strategies of target bacteria, E. faecalis is not dependent on the electrode for energy, and it is only necessary to capture small amounts of an organism’s metabolic energy to, in this case 1.6%, to achieve good detection. The results pave the way for new means of detecting an industrially important group of organisms, particularly in the food industry.

Original languageEnglish
Article number1257
JournalApplied Sciences (Switzerland)
Volume12
Issue number3
Early online date25 Jan 2022
DOIs
Publication statusPublished - 1 Feb 2022
Externally publishedYes

Keywords

  • E. faecalis
  • Extracellular electron transfer
  • Lactic acid bacteria
  • Microbial detection
  • Redox mediator

ASJC Scopus subject areas

  • Materials Science(all)
  • Instrumentation
  • Engineering(all)
  • Process Chemistry and Technology
  • Computer Science Applications
  • Fluid Flow and Transfer Processes

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