Periodic step polarization accelerates electron recovery by electroactive biofilms (EABs).

Area of Science:

• Bioelectrochemistry
• Microbial electrochemistry
• Bioelectrochemical systems (BES)

Background:

• Low electron recovery rates hinder the advancement of bioelectrochemical systems.
• Electroactive biofilms (EABs) and Geobacter sulfurreducens biofilms are crucial for electron transfer.

Purpose of the Study:

• To investigate new periodic polarization methods to enhance electron recovery in BES.
• To compare the efficiency of new polarization schemes against traditional methods.

Main Methods:

• Utilized localized cyclic voltammetry to identify redox centers in EABs and G. sulfurreducens biofilms.
• Applied new periodic polarizations, including periodic step polarization, discharging at 0.4 V.
• Employed quantitative reverse transcription polymerase chain reaction (RT-qPCR) to analyze gene expression.

Main Results:

• Periodic polarizations discharging at 0.4 V accelerated electron recovery compared to fixed-potential methods.
• The best-performing periodic step polarization increased electron recovery by 23%-24% for EABs and 12%-76% for G. sulfurreducens biofilms.
• RT-qPCR revealed increased omcZ mRNA transcripts in G. sulfurreducens after periodic step polarization.

Conclusions:

• Optimized polarization schemes can significantly enhance the rate of energy recovery in BES.
• Periodic step polarization is an effective strategy for improving the performance of EABs and G. sulfurreducens biofilms.
• Advancements in polarization techniques are key to overcoming limitations in current bioelectrochemical systems.