1 research outputs found
Anode Biofilms of <i>Geoalkalibacter ferrihydriticus</i> Exhibit Electrochemical Signatures of Multiple Electron Transport Pathways
Thriving
under alkaliphilic conditions, <i>Geoalkalibacter
ferrihydriticus</i> (<i>Glk. ferrihydriticus</i>) provides
new applications in treating alkaline waste streams as well as a possible
new model organism for microbial electrochemistry. We investigated
the electrochemical response of biofilms of the alkaliphilic anode-respiring
bacterium (ARB) <i>Glk. ferrihydriticus</i> voltammetry
(CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry.
We observed there to be at least four dominant electron transfer pathways,
with their contribution to the overall current produced dependent
on the set anode potential. These pathways appear to be manifested
at midpoint potentials of approximately −0.14 V, −0.2
V, −0.24 V, and −0.27 V vs standard hydrogen electrode.
The individual contributions of the pathways change upon equilibration
from a set anode potential to another anode potential. Additionally,
the contribution of each pathway to the overall current produced is
reversible when the anode potential is changed back to the original
set potential. The pathways involved in anode respiration in <i>Glk. ferrihydriticus</i> biofilms follow a similar, but more
complicated, pattern as compared to those in the model ARB, <i>Geobacter sulfurreducens</i>. This greater diversity of electron
transport pathways in <i>Glk. ferrihydriticus</i> could
be related to its wider metabolic capability (e.g., higher pH and
larger set of possible substrates, among others)