Modelling extracellular limitations for mediated versus direct interspecies electron transfer

Storck, Tomas, Virdis, Bernardino and Batstone, Damien J. (2015) Modelling extracellular limitations for mediated versus direct interspecies electron transfer. ISME Journal, 10 3: 1-11. doi:10.1038/ismej.2015.139

Author Storck, Tomas
Virdis, Bernardino
Batstone, Damien J.
Title Modelling extracellular limitations for mediated versus direct interspecies electron transfer
Journal name ISME Journal   Check publisher's open access policy
ISSN 1751-7370
Publication date 2015-11-06
Sub-type Article (original research)
DOI 10.1038/ismej.2015.139
Open Access Status Not Open Access
Volume 10
Issue 3
Start page 1
End page 11
Total pages 11
Place of publication London, United Kingdom
Publisher Nature Publishing Group
Language eng
Formatted abstract
Interspecies electron transfer (IET) is important for many anaerobic processes, but is critically dependent on mode of transfer. In particular, direct IET (DIET) has been recently proposed as a metabolically advantageous mode compared with mediated IET (MIET) via hydrogen or formate. We analyse relative feasibility of these IET modes by modelling external limitations using a reaction-diffusion-electrochemical approach in a three-dimensional domain. For otherwise identical conditions, external electron transfer rates per cell pair (cp) are considerably higher for formate-MIET (317 × 103 e cp−1 s−1) compared with DIET (44.9 × 103 e cp−1 s−1) or hydrogen-MIET (5.24 × 103 e cp−1 s−1). MIET is limited by the mediator concentration gradient at which reactions are still thermodynamically feasible, whereas DIET is limited through redox cofactor (for example, cytochromes) activation losses. Model outcomes are sensitive to key parameters for external electron transfer including cofactor electron transfer rate constant and redox cofactor area, concentration or count per cell, but formate-MIET is generally more favourable for reasonable parameter ranges. Extending the analysis to multiple cells shows that the size of the network does not strongly influence relative or absolute favourability of IET modes. Similar electron transfer rates for formate-MIET and DIET can be achieved in our case with a slight (0.7 kJ mol−1) thermodynamic advantage for DIET. This indicates that close to thermodynamic feasibility, external limitations can be compensated for by improved metabolic efficiency when using direct electron transfer.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2016 Collection
Advanced Water Management Centre Publications
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