Lyophilization

Definition

Lyophilization, also known as freeze-drying, is a dehydration process used to preserve perishable materials by freezing them and then reducing the surrounding pressure to allow the frozen water to sublimate directly from the solid phase to the gas phase. This technique is widely used in microbiology for preserving microbial cultures.

5 Must Know Facts For Your Next Test

1. Lyophilization effectively preserves microorganisms by halting their metabolic activities.
2. The process involves three main stages: freezing, primary drying (sublimation), and secondary drying (desorption).
3. Microbial cultures preserved via lyophilization can be rehydrated and revived with minimal loss of viability.
4. Lyophilized samples have long shelf lives and are stable at room temperature, making them ideal for storage and transportation.
5. This method minimizes thermal damage to microorganisms compared to other dehydration methods like heat drying.

Review Questions

• What are the three main stages involved in lyophilization?
• Why is lyophilization preferred over heat drying for preserving microbial cultures?
• How does lyophilization contribute to the long-term storage and stability of microorganisms?

Related terms

Desiccation:

A method of removing moisture from materials, often used to inhibit microbial growth.

Cryopreservation:

A process where cells or whole tissues are preserved by cooling to sub-zero temperatures.

Sublimation: The transition of a substance directly from the solid phase to the gas phase without passing through the liquid phase.