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Self-standing Electrochemical Set-up to Enrich Anode-respiring Bacteria On-site
Published on: July 24, 2018
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Superior anodic electro-fermentation by enhancing capacity for extracellular electron transfer.
Liuyan Gu1, Xinxin Xiao2, Sang Yup Lee3
1National Food Institute, Technical University of Denmark, Kongens Lyngby, 2800, Denmark.
Bioresource Technology
|September 30, 2023
Summary
Anodic electro-fermentation (AEF) uses anodes as electron acceptors. An evolved Lactococcus lactis strain showed faster growth and produced more 2,3-butanediol using an anode in a bioelectrochemical system (BES).
Area of Science:
- Microbiology
- Bioelectrochemistry
- Metabolic Engineering
Background:
- Anodic electro-fermentation (AEF) offers a promising alternative to traditional fermentation by using an anode as the terminal electron acceptor.
- Lactococcus lactis strains engineered for NAD+ regeneration can utilize ferricyanide, but high concentrations limit practical use.
- Adaptive evolution can enhance microbial capabilities for bioelectrochemical systems.
Purpose of the Study:
- To investigate the growth and metabolite production of a wild-type Lactococcus lactis strain and an adaptively evolved (ALE) mutant using an anode as the electron acceptor in a bioelectrochemical system (BES).
- To compare the performance of the ALE mutant with enhanced ferricyanide respiration capacity against the parent strain in AEF.
- To assess the potential of Lactic Acid Bacteria in AEF applications.
Main Methods:
- Utilizing a bioelectrochemical system (BES) setup for anodic electro-fermentation (AEF).
- Culturing a wild-type Lactococcus lactis strain and an adaptively evolved (ALE) mutant.
- Measuring growth rates, metabolite production (acetoin, 2,3-butanediol), and current density generated by the microbial communities.
Main Results:
- Both L. lactis strains demonstrated growth using the anode as an electron acceptor.
- The ALE mutant exhibited significantly faster growth compared to the parent strain.
- The ALE mutant predominantly produced 2,3-butanediol, while the parent strain produced mainly acetoin.
- The ALE mutant achieved a high current density of 0.81 ± 0.05 mA/cm², indicating efficient interaction with the anode.
Conclusions:
- Adaptive evolution significantly enhances the performance of Lactococcus lactis in anodic electro-fermentation (AEF).
- The ALE mutant's ability to efficiently utilize an anode demonstrates the potential of Lactic Acid Bacteria in bioelectrochemical applications.
- AEF with evolved strains offers a sustainable approach for producing valuable chemicals like 2,3-butanediol.
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