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Investigating luxS gene expression in lactobacilli along lab-scale cocoa fermentations
O G G Almeida1, M G Pereira2, R L Bighetti-Trevisan3
1Universidade de São Paulo, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Brazil.
Food Microbiology
|January 15, 2024
Summary
Lactic acid bacteria in cocoa fermentation express Quorum Sensing (QS) genes, specifically luxS. Lactiplantibacillus plantarum showed continuous luxS expression, potentially impacting fermentation quality negatively.
Area of Science:
- Food Microbiology
- Fermentation Science
- Molecular Biology
Background:
- Metagenomic studies suggest lactobacilli utilize Quorum Sensing (QS) in cocoa fermentation.
- luxS is a conserved gene marker for QS systems in bacteria.
Purpose of the Study:
- To investigate luxS gene expression in lactobacilli during cocoa fermentation.
- To correlate QS activity with microbial succession, enzymatic profiles, and volatile compounds.
Main Methods:
- Laboratory-scale cocoa fermentations with defined microbial inocula.
- Monitoring microbial counts, enzyme activity, and volatile compounds (GC-MS).
- Quantifying luxS gene expression using Reverse Transcriptase Real-Time PCR.
Main Results:
- Microbial succession was observed, but no significant differences in microbial enumeration or alpha-diversity.
- Lactiplantibacillus plantarum exhibited continuous luxS expression throughout fermentation.
- Limosilactobacillus fermentum showed luxS expression only in early and middle stages.
- A potential negative correlation between Lp. Plantarum luxS expression and fermentation quality was noted.
Conclusions:
- Confirms luxS expression by lactobacilli during cocoa fermentation, supporting prior metagenomic findings.
- Lactiplantibacillus plantarum is identified as the primary lactic acid bacterium expressing luxS in this context.
- The continuous luxS expression by Lp. Plantarum may negatively influence cocoa fermentation quality.
