Bacteriocin-Producing Enterococci Modulate Cheese Microbial Diversity

Area of Science:

• Food Microbiology
• Microbial Ecology
• Dairy Science

Background:

• Lactic acid bacteria (LAB) are crucial for cheese production, influencing flavor and texture through nutrient breakdown.
• Microbial community composition in cheese is affected by environmental factors and microbial interactions.
• The role of bacteriocins, antimicrobial peptides produced by LAB, in shaping these communities is not fully understood.

Purpose of the Study:

• To investigate the impact of bacteriocin production on lactic acid bacteria (LAB) diversity in cheese.
• To use Enterococcus, a known bacteriocin producer, as a model organism for this study.
• To analyze how bacteriocin-producing bacteria influence the overall microbial and specific enterococcal populations in cheese.

Main Methods:

• Antimicrobial assays were used to detect enterocin production by enterococcal isolates.
• 16S rRNA gene amplicon metagenomic sequencing analyzed the total microbial community diversity in raw milk cheeses.
• Multi-locus sequence analysis (MLSA) assessed the diversity within enterococcal populations.

Main Results:

• LAB communities in cheese were primarily composed of Lactococci, Lactobacilli, and Streptococci, with Enterococci present in smaller quantities.
• Cheeses containing bacteriocin-producing Enterococcus isolates displayed significantly higher overall microbial diversity.
• The positive effect of bacteriocin producers on diversity was observed at low producer concentrations and was not evident within the Enterococcus populations themselves.

Conclusions:

• Bacteriocin production by LAB, particularly Enterococcus, plays a significant role in structuring lactic acid bacterial communities during cheese ripening.
• The findings highlight bacteriocins as key modulators of microbial diversity in fermented foods.
• Further research is warranted to explore the broader ecological implications of bacteriocin-mediated interactions in diverse microbial ecosystems.