Fungal cultures

Dr. Gauri S. Bapat

by

Fungal culture methodology is the foundation of fundamental and applied research as well as the

commercial exploitation of fungi

What do we do to Fungal cultures in laboratory

Growth

Purification

Preservation

Types of substrates for Fungal cultures

Soild substrate

Agar media Liquid mediaAgar-agar- =Othersubstrates

Naturalmedia

Semi-syntheticmedia

Syntheticmedia

Growing Fungi in Laboratory

Limiting Factors for the Growth of Fungi

Temperature Light Aeration Humidity

Why Pure cultures are necessary?

Detect Isolate Identify Quantify Multiply Utilize

Why Preserve Fungal Cultures ?

Fungal cultures are the genetic resource.

Germplasm conservation

Developmental studies

Industrial Application.

Research programs.

Contaminants

Fungi Bacteria Mites

Techniques for elimination

*Serialdilution

*Singlesporeisolation

*Ultra violateirradiation

*Selectivemedium withantibiotic

*Exclusion

*Fumigation

1. Periodic transfer

2. Sterile mineral oil

3. Sterile water

4. Sterile soil or sand

5. Silica gel

6. Drying on organic substrates

7. L-drying

8. Mechanical freezers

9. Lyophilization

Preservation Techniques

Periodic transfer

Advantages Easy Inexpensive Requires no special

equipment

Disadvantages Labor- intensive May induce variation May acquire

contamination Time demanding

Sterile water

Advantages Clean Quick Easy Less expensive Requires no special

equipment Greater genetic

stability Works for all fungi

Disadvantages Viability loss due to

toxin traces in water Viability upto 6 years

Sterile mineral OilAdvantages Easy Less expensive Requires no special

equipment Limits mite-

contamination Viability reported

upto 32 years

Disadvantages Does not work well

for all fungi Retarded growth after

retrieval Messy Risk of contamination

at retrieval

Sterile Soil / Sand/ SilicaAdvantages Less expensive Technically simple Requires no special

equipment Vigor maintained Can produce uniform

inoculum

Disadvantages Work well for

sporulating fungi Viability upto 8 years

Drying on organic substrates

Advantages Less expensive Used for specialized

groups of fungi

Disadvantages Perfection in handling

is essential for ensuring loss of viability

Risk of contamination at retrieval

Lyophilization

Advantages Long viability Ensured protection

against contamination Works well for all

fungi

Disadvantages Expensive technique Complex technique Many copies are

needed as some isolates fail to survive

Viability needs many trials

Broader perspective : Fungal culture collection

system

Culture Accession process

Culture preservation process

Culture maintenance process