Question

Which of the following is used for the preservation of culture for sporulating mycelial microorganisms?

• A. Dried soil
• B. Dried potato
• C. Glass bead
• D. Dried bread

Hint:

While soil preservation is excellent for spore-forming fungi, non-sporulating vegetative bacteria and delicate yeasts are typically preserved using lyophilization (freeze-drying) or cryopreservation in liquid nitrogen (\(-196^\circ\text{C}\)) using glycerol as a cryoprotectant.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Maintaining pure cultures of industrial microorganisms requires preservation techniques that prevent genetic mutation, contamination, and loss of viability over long storage periods.

Step 2: Detailed Explanation:
For sporulating mycelial microorganisms, such as filamentous fungi (molds) and actinomycetes, soil preservation (using sterile dried soil) is a classic, highly effective, and low-cost long-term preservation method.
In this technique:
- Rich soil is sterilized repeatedly to destroy all native organisms.
- A spore suspension of the fungus is inoculated into the sterile soil.
- The soil is allowed to dry gradually under clean conditions, which induces the mycelia to form stable, dormant spores.
- These dormant spores remain viable, genetically stable, and protected inside the dry soil particles for several years at room temperature or under refrigeration.

Step 3: Final Answer:
The material used is Dried soil, which corresponds to option (A).