A1 Refereed original research article in a scientific journal
Fourfold increase in photocurrent generation of Synechocystis sp. PCC 6803 by exopolysaccharide deprivation
Authors: Wey, Laura T.; Wroe, Evan Indigo; Sadilek, Viktor; Shang, Linying; Chen, Xiaolong; Zhang, Jenny Z.; Howe, Christopher J.
Publisher: PERGAMON-ELSEVIER SCIENCE LTD
Publishing place: OXFORD
Publication year: 2024
Journal: Electrochimica Acta
Journal name in source: ELECTROCHIMICA ACTA
Journal acronym: ELECTROCHIM ACTA
Article number: 144555
Volume: 497
Number of pages: 12
ISSN: 0013-4686
eISSN: 1873-3859
DOI: https://doi.org/10.1016/j.electacta.2024.144555
Web address : https://doi.org/10.1016/j.electacta.2024.144555
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/457386444
Photosynthetic microorganisms, including algae and cyanobacteria, export electrons in a light-stimulated phenomenon called 'exoelectrogenesis'. However, the route(s) by which electrons reach an external electrode from the cell remain(s) unclear. For the model cyanobacterium Synechocystis sp. PCC 6803, it has been established that electron transfer does not depend on direct extracellular electron transfer by type IV pili. However, the role of the exopolysaccharide matrix in which cells are embedded has not been investigated. We show that a Synechocystis mutant with substantially reduced exopolysaccharide production has a four-fold greater photocurrent than wildtype cells. This increase is due in part to increased adhesion of exopolysaccharide-deficient cells to electrodes. Stirred system experiments reveal that a substantial portion of the photocurrent depends on an endogenous diffusible electron mediator, supporting indirect extracellular electron transfer as the bioelectrochemical mechanism of exoelectrogenesis. These findings will be important in harnessing exoelectrogenesis for sustainable electricity generation in biophotovoltaic devices.
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Funding information in the publication:
This work was supported by the Cambridge Trust (to L.T.W. and L.S.), UK Research and Innovation ( BB/R011923/1 to J.Z.Z., BB/M011194/1 to E.W.), China Scholarship Council (to L.S.), and the Novo Nordisk Foundation ( NNF22OCOO79717 to L.T.W.). The Synechocystis sp. PCC 6803 EPS mutant and background wild-type strain were a gift from Prof. Franck Chauvat (Institut de Biologie Intégrative de la Cellule (I2BC), France). The differently sized wild-type strains Arizona and Imperial were a gift from Prof. Conrad Mullineaux (Queen Mary University of London, UK).
