Disentangling extracellular current of electroactive bacteria with oblique-incidence reflection difference imaging

Area of Science:

• Microbiology
• Electrochemistry
• Biotechnology

Background:

• Extracellular electron transfer (EET) in electroactive bacteria is crucial for understanding microbial processes.
• Differentiating direct (DET) and mediated (MET) electron transfer pathways within the total EET current is a significant challenge.

Purpose of the Study:

• To develop a method for disentangling and quantifying DET and MET currents in electroactive bacteria.
• To enable precise measurement of individual bacterial EET contributions.

Main Methods:

• Utilized a spatiotemporally-resolved oblique-incidence reflection difference (OIRD) technique.
• Employed a polyaniline (PANI)-based dual electrode system to translate charge information into OIRD signals.
• Manipulated PANI reduction states to selectively switch off local EET and measure MET currents.

Main Results:

• Successfully disentangled the integrated EET current into distinct DET and MET components.
• Quantified the average currents contributed by individual bacteria through each pathway.
• Demonstrated the capability of the OIRD-PANI system to map and measure EET currents.

Conclusions:

• The developed method provides a robust approach for differentiating DET and MET pathways in electroactive bacteria.
• This technique offers valuable insights into the mechanisms of microbial extracellular electron transfer.
• The findings may advance research in bioelectrochemical systems and microbial fuel cells.