Marine phototrophic consortia transfer electrons to electrodes in response to reductive stress.
Libertus DarusPablo LedezmaJürg KellerStefano FreguiaPublished in: Photosynthesis research (2015)
This work studies how extracellular electron transfer (EET) from cyanobacteria-dominated marine microbial biofilms to solid electrodes is affected by the availability of inorganic carbon (Ci). The EET was recorded chronoamperometrically in the form of electrical current by a potentiostat in two identical photo-electrochemical cells using carbon electrodes poised at a potential of +0.6 V versus standard hydrogen electrode under 12/12 h illumination/dark cycles. The Ci was supplied by the addition of NaHCO3 to the medium and/or by sparging CO2 gas. At high Ci conditions, EET from the microbial biofilm to the electrodes was observed only during the dark phase, indicating the occurrence of a form of night-time respiration that can use insoluble electrodes as the terminal electron acceptor. At low or no Ci conditions, however, EET also occurred during illumination suggesting that, in the absence of their natural electron acceptor, some cyanobacteria are able to utilise solid electrodes as an electron sink. This may be a natural survival mechanism for cyanobacteria to maintain redox balance in environments with limiting CO2 and/or high light intensity.
Keyphrases
- electron transfer
- reduced graphene oxide
- carbon nanotubes
- solid state
- solar cells
- microbial community
- gold nanoparticles
- induced apoptosis
- pseudomonas aeruginosa
- staphylococcus aureus
- risk assessment
- cell cycle arrest
- escherichia coli
- high intensity
- oxidative stress
- high resolution
- human health
- liquid chromatography
- climate change
- carbon dioxide