Functional properties of plasmids in lactic streptococci

Area of Science:

• Microbiology
• Molecular Biology
• Dairy Science

Background:

• Plasmids are crucial in dairy starter cultures, influencing vital milk fermentation properties.
• Many metabolic traits in lactic streptococci are known to be plasmid-mediated.

Purpose of the Study:

• To review and consolidate evidence for plasmid-mediated traits in lactic streptococci.
• To identify traits requiring further genetic confirmation of plasmid linkage.

Main Methods:

• Review of existing literature on plasmid biology in lactic streptococci.
• Analysis of phenotypic and genetic evidence for plasmid-trait associations.
• Categorization of traits based on the strength of evidence for plasmid linkage.

Main Results:

• Established plasmid linkage for lactose utilization and bacteriocin production.
• Phenotypic and physical evidence supports plasmid linkage for traits like citrate, sucrose, and nisin production.
• Some traits, including sensitivity to inhibitory systems and slime production, are speculatively linked to plasmids.

Conclusions:

• Plasmids play a significant role in the functionality of dairy starter cultures.
• Further genetic studies are essential to confirm plasmid associations for numerous metabolic and functional traits.
• Understanding plasmid biology is key to optimizing dairy fermentation processes.