Mixed Conducting Polymers Alter Electron Transfer Thermodynamics to Boost Current Generation from Electroactive...

Area of Science:

• Microbiology
• Electrochemistry
• Bioenergetics

Background:

• Electroactive microbes are vital in ecosystems and for alternative energy.
• Small-molecule mediators facilitate microbial electron transfer but are challenging to study due to differing electron transfer mechanisms in native vs. electrochemical systems.

Purpose of the Study:

• To develop a method for studying concerted two-electron transfer in electroactive microbes.
• To engineer electrode interfaces that mimic native microbial electron transfer.

Main Methods:

• Modification of electrodes with ion- and electron-conductive polymers.
• Cultivation of *Shewanella oneidensis* biofilms on modified electrodes.
• Electrochemical analysis of electron transfer processes.

Main Results:

• Achieved biosimilar, concerted two-electron transfer from *Shewanella oneidensis* via flavin mediators.
• Observed significantly improved per-microbe current generation in biofilms on modified electrodes.
• Demonstrated biofilm morphologies that more closely resemble native systems.

Conclusions:

• Polymer-modified electrodes enable biologically relevant studies of electroactive biofilms.
• Altered mediator electron transfer thermodynamics facilitate unprecedented concerted electron transfer.
• Findings pave the way for understanding microbial ecology and advancing sustainable technologies.