High-throughput ecological interaction mapping of dairy microorganisms.

Area of Science:

• Microbiology
• Food Science
• Ecology

Background:

• Microbial communities are vital for food processes.
• Lactic acid bacteria (LAB) interactions are complex and understudied.
• Understanding these dynamics is crucial for efficient microbial management.

Purpose of the Study:

• To explore binary interactions within a mock community of 94 dairy-associated microbial strains.
• To quantify and classify the ecological types of these interactions.
• To investigate how microbial origin influences interaction dynamics.

Main Methods:

• Utilized a colony-picking robot for high-throughput screening.
• Measured bidirectional interactions on solid media over seven days.
• Employed image analysis to classify 1,142 interactions.

Main Results:

• Observed significant variation in interaction strength, directionality, and type.
• Cooperation increased from raw milk to pasteurized milk and cheese strains.
• Exploitative interactions were more prevalent in raw milk strains.
• Cooperating strains showed similar ecological behaviors, suggesting microbial cliques.
• A novel pink-red pigmentation was observed for Lactococcus cremoris ATCC 19257 with Pseudomonas aeruginosa.

Conclusions:

• The study provides a large dataset on microbial interactions at a system level.
• Findings enhance understanding of ecological dynamics in food-associated microbial communities.
• Results have potential applications in selecting strains for food fermentation, bioprotection, and probiotics.