Methods for increasing survivability during storage of exponentially growing bacteria

Area of Science:

• Microbiology
• Bacterial Physiology

Background:

• Maintaining bacterial viability during storage is crucial for research and diagnostics.
• Current methods often result in significant loss of culturability over time.

Purpose of the Study:

• To develop and optimize a protocol for long-term storage of Gram-negative bacterial cells at 0°C.
• To assess the efficacy of the protocol across different bacterial species.

Main Methods:

• Storage of bacterial cells (Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus) at 0°C.
• Optimization of carbon starvation duration (5-12 hours) and addition of chloramphenicol (750 µg/ml).
• Assessment of colony-forming ability over a 60-day period.

Main Results:

• The protocol achieved >90% survival for Escherichia coli and Pseudomonas aeruginosa after 60 days at 0°C.
• Bacillus cereus survivability was not enhanced by this protocol.
• Optimal survival was achieved with 9 hours of carbon starvation and chloramphenicol supplementation.

Conclusions:

• A robust protocol for preserving Gram-negative bacterial viability at 0°C has been established.
• The protocol demonstrates species-specific efficacy, highlighting the importance of bacterial physiology in storage.
• Further research may explore variations for other bacterial types.