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Characterizing Mediated Extracellular Electron Transfer in Lactic Acid Bacteria with a Three-Electrode, Two-Chamber Bioelectrochemical System
Published on: August 23, 2024
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The proteolytic systems of lactic acid bacteria
E R Kunji1, I Mierau, A Hagting
1Department of Microbiology, University of Groningen, Haren, The Netherlands.
Antonie Van Leeuwenhoek
|October 1, 1996
Summary
Dairy lactic acid bacteria utilize a similar proteolytic system, involving extracellular proteinases and intracellular peptidases. Oligopeptide transport is key for nitrogen uptake, with coordinated enzyme action essential for peptide breakdown.
Area of Science:
- Microbiology
- Enzymology
- Dairy Science
Background:
- Proteolysis is crucial for lactic acid bacteria (LAB) growth and metabolism.
- Previous research has extensively investigated LAB proteolytic systems using various methodologies.
Purpose of the Study:
- To review and synthesize current knowledge on the proteolytic systems of lactococci and lactobacilli.
- To present a model for the proteolytic pathway based on genetic, biochemical, and ultrastructural data.
Main Methods:
- Genetic, biochemical, and ultrastructural analyses.
- In vitro enzyme and transporter studies.
- Targeted mutational techniques for in vivo investigations.
Main Results:
- Proteolytic systems of lactococci and lactobacilli share similar components and mechanisms.
- Key components include extracellular serine-proteinases, oligopeptide transporters, and intracellular peptidases.
- Oligopeptide transport is the primary nitrogen acquisition route; intracellular peptidases act concertedly for complete peptide degradation.
Conclusions:
- A unified model for LAB proteolysis highlights the importance of extracellular proteinases, efficient oligopeptide transport, and intracellular peptidase activity.
- This system is vital for nitrogen assimilation and amino acid production in dairy LAB.
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