TY - JOUR
T1 - Extracellular Electron Transfer of Weak Electricigens in the Presence of a Competing Electron Acceptor
AU - Aiyer, Kartik
AU - Doyle, Lucinda E.
N1 - Publisher Copyright:
© 2023 The Electrochemical Society (“ECS”). Published on behalf of ECS by IOP Publishing Limited.
PY - 2023
Y1 - 2023
N2 - To maximise microbial electroactivity in bioelectrochemical systems, soluble electron acceptors are typically omitted as they compete with the electrode. While practical, this approach provides engineered conditions that do not reflect the natural environment of electroactive microorganisms, which may contain both soluble and insoluble electron acceptors. This study investigates the behaviour of weak electricigens, a relatively understudied category of microorganisms whose members switch between non-electroactive and electroactive states. Enrichments were performed in microbial fuel cells containing both an electrode and the soluble alternative fumarate to probe extracellular electron transfer of weak electricigens. Using fluorescence spectroscopy, chromatography and voltammetry, the electron shuttle riboflavin was not found in these conditions but was found in controls in which only the electrode was available to reduce. Despite this dichotomy in ability to perform riboflavin-based mediated electron transfer, communities of weak electricigens were similarly electroactive in each condition (19.36 ± 0.9 mW m−2 vs 20.25 ± 2.0 mW m−2). 16S rRNA gene sequencing revealed similar communities enriched in each condition, but with differing abundance. Understanding extracellular electron transfer in natural environments is of both fundamental and applied interest, as it can inform the design of real-world bioelectrochemical systems whose influents are likely to contain competing electron acceptors.
AB - To maximise microbial electroactivity in bioelectrochemical systems, soluble electron acceptors are typically omitted as they compete with the electrode. While practical, this approach provides engineered conditions that do not reflect the natural environment of electroactive microorganisms, which may contain both soluble and insoluble electron acceptors. This study investigates the behaviour of weak electricigens, a relatively understudied category of microorganisms whose members switch between non-electroactive and electroactive states. Enrichments were performed in microbial fuel cells containing both an electrode and the soluble alternative fumarate to probe extracellular electron transfer of weak electricigens. Using fluorescence spectroscopy, chromatography and voltammetry, the electron shuttle riboflavin was not found in these conditions but was found in controls in which only the electrode was available to reduce. Despite this dichotomy in ability to perform riboflavin-based mediated electron transfer, communities of weak electricigens were similarly electroactive in each condition (19.36 ± 0.9 mW m−2 vs 20.25 ± 2.0 mW m−2). 16S rRNA gene sequencing revealed similar communities enriched in each condition, but with differing abundance. Understanding extracellular electron transfer in natural environments is of both fundamental and applied interest, as it can inform the design of real-world bioelectrochemical systems whose influents are likely to contain competing electron acceptors.
U2 - 10.1149/1945-7111/accf3e
DO - 10.1149/1945-7111/accf3e
M3 - Journal article
AN - SCOPUS:85158044393
SN - 0013-4651
VL - 170
JO - Journal of The Electrochemical Society
JF - Journal of The Electrochemical Society
IS - 5
M1 - 055501
ER -