Mediator-Microorganism Interaction in Microbial Solar Cell: a Fluo-Electrochemical Insight

Microbial
solar cells that mainly rely on the use of photosynthesic
organisms are a promising alternative to photovoltaics for solar electricity
production. In that way, we propose a new approach involving electrochemistry
and fluorescence techniques. The coupled setup Electro-Pulse-Amplitude-Modulation
(“e-PAM”) enables the simultaneous recording of the
produced photocurrent and fluorescence signals from the photosynthetic
chain. This methodology was validated with a suspension of green alga Chlamydomonas reinhardtii in interaction with an
exogenous redox mediator (2,6-dichlorobenzoquinone; DCBQ). The balance
between photosynthetic chain events (PSII photochemical yield, quenching)
and the extracted electricity can be monitored overtime. More particularly,
the nonphotochemical quenching induced by DCBQ mirrors the photocurrent.
This setup thus helps to distinguish the electron harvesting from
some side effects due to quinones in real time. It therefore paves
the way for future analyses devoted to the choice of the experimental
conditions (redox mediator, photosynthetic organisms, and so on) to
find the best electron extraction.