436: Copper Concentrates Culture Current

This episode: Copper electrodes, rather than killing bacteria in
microbial fuel cells, allow them to generate higher densities of
electric current!


Download Episode (5.0 MB, 7.2 minutes)

Show notes:
Microbe of the episode: Xipapillomavirus 2


 


News item



Takeaways


Copper is widely used as a way to make surfaces and materials
antimicrobial, to cut down on the spread of pathogens in
hospitals and other environments. Among other mechanisms, it
reacts with oxygen to form reactive oxygen species that are
very harsh on microbial proteins. But copper is also a good
electrical conductor, which would be useful to use in
microbial fuel cells, which exploit bacterial metabolism to
generate electricity. Microbes form biofilms on an electrode
and transfer electrons to it as a way for them to generate
energy. Most such fuel cells have used graphite electrodes to
avoid toxicity.


 


In this study, fuel cell bacteria grew well on a copper
electrode in an oxygen-free environment. The copper actually
allowed them to increase the amount of current they produced
per unit of area, as ionic copper diffused through the
biofilm and allowed electrons to flow through the biofilm to
the electrode from layers farther from the electrode that
otherwise would not have access. Even graphite electrodes
could be improved by adding these copper ions to the biofilm
directly.


Journal Paper:
Beuth L, Pfeiffer CP, Schröder U. 2020. Copper-bottomed:
electrochemically active bacteria exploit conductive sulphide
networks for enhanced electrogeneity. Energy Environ Sci
13:3102–3109.


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