Bacterial Inhibition Mechanism of Rhamnolipid-Modified β-Carotene/Rutinoside Complex Liposomes

Area of Science:

• Food Science
• Microbiology
• Biotechnology

Background:

• Foodborne pathogenic microorganisms pose significant health risks.
• Development of novel antimicrobial agents is crucial for food safety.
• Encapsulation systems offer potential for enhanced bioactivity.

Purpose of the Study:

• To develop and characterize a cholesterol-free delivery system, RL-βC-Rts.
• To evaluate the antibacterial efficacy of RL-βC-Rts against key foodborne pathogens.
• To elucidate the mechanism of antibacterial action of RL-βC-Rts.

Main Methods:

• Synthesis of RL-βC-Rts using rhamnolipid (RL) surfactant encapsulating β-carotene (βC) and rutinoside (Rts).
• Bacterial viability assays and determination of Minimum Inhibitory Concentration (MIC).
• Cell membrane potential analysis using fluorescence intensity measurements.
• Protein concentration analysis and RT-qPCR for gene expression profiling.

Main Results:

• RL-βC-Rts exhibited significant antibacterial activity against *Escherichia coli*, *Staphylococcus aureus*, *Listeria monocytogenes*, and *Salmonella typhimurium*.
• Observed reduction in bacterial cell membrane potential, indicating membrane damage.
• Discharge of intracellular proteins and alterations in protein concentration confirmed membrane integrity disruption.
• Suppression of key genes involved in energy metabolism, DNA metabolism, and virulence was noted via RT-qPCR.

Conclusions:

• RL-βC-Rts is an effective cholesterol-free antimicrobial agent against common foodborne pathogens.
• The antibacterial mechanism involves disruption of bacterial cell membrane integrity and inhibition of essential cellular processes.
• This novel delivery system holds promise for enhancing food safety and preservation.