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Updated: Mar 23, 2026

Characterizing Mediated Extracellular Electron Transfer in Lactic Acid Bacteria with a Three-Electrode, Two-Chamber Bioelectrochemical System
Published on: August 23, 2024
Bias voltage enhances extracellular polymeric substances-mediated extracellular electron transport
Hongzhou Liu1, Sijie Gu1, Xiaoxue Tang1
1School of Energy and Environmental Science, Yunnan Normal University, Kunming, Yunnan 650500, China.
Bias voltage significantly enhances extracellular electron transfer (EET) in bioelectrochemical systems by altering microbial extracellular polymeric substances (EPS). This modification optimizes EPS composition and structure, boosting EET efficiency.
Area of Science:
- Bioelectrochemistry
- Microbial electrochemistry
- Biomaterials science
Background:
- Low extracellular electron transfer (EET) efficiency is a major limitation in bioelectrochemical systems (BES).
- Extracellular polymeric substances (EPS) are crucial interfaces in BES, mediating microbial-electrode electron exchange.
- The electrochemical properties of EPS directly impact EET rates.
Purpose of the Study:
- To investigate how bias voltage (BV) affects EPS composition and structure.
- To elucidate the mechanism by which BV enhances EPS-mediated EET.
- To optimize EPS electrochemical properties for improved BES performance.
Main Methods:
- Application of bias voltage (BV) to bioelectrochemical systems.
- Multi-scale characterization of extracellular polymeric substances (EPS).
- Analysis of EPS protein secondary structure and redox mediator content.
Main Results:
- BV induced a shift in EPS protein secondary structure from β-sheets to β-turns.
- BV significantly enriched humic acid substances (up to 21.4%) and cytochrome c (up to 110.6%).
- An optimal BV of 0.4 V balanced redox components, enhancing EPS electrochemical activity and EET rate by 24.6%.
Conclusions:
- Bias voltage is an effective strategy to enhance EPS-mediated EET in BES.
- BV modulates EPS composition and structure, creating an optimized mediator system.
- This study provides key insights into the role of EPS in EET and BES performance.
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