Cultivation of Fungi and Classification of Fungi

Cultivation of Fungi and Classification of Fungi by Sadia Akhtar

Cultivation of Fungi and Classification of Fungi

Fungi are microscopic and eukaryotic organisms, unicellular or multicellular. There are more than 100,000 species of fungi that have been identified. Fungi grow slowly than bacteria.

 Classification of Fungi

Fungi are usually classified into four divisions, based on the way in which the fungus reproduces sexually.

1. Chytridiomycota (chytrids) – for example, Batrachochytrium dendrobatidis, Allomyces sp.

2. Zygomycota (bread molds) – for example, Rhizopus stolonifer

3. Ascomycota (yeasts and sac fungi) – for example, Candida albicans, Aspergillus oryzae

     4. Basidiomycota (club fungi) – for example, Cryptococcus neoformans causing severe respiratory illness.

Cultivation of Fungi

Most of the fungi usually grow on the various types of culture media at temperature ranging from 20-30°C in the presence of oxygen.

Acidic bacteria that incorporate a relatively high concentration of sugar are tolerated by molds but are inhibitory to many bacteria. Each fungus has its own specific requirements which may be known experimentally. Most fungi are able to synthesize the vitamins in their need.

However, several fungi may need thiamine or biotin or both of these vitamins are generally added to synthetic media.

When fungi are cultured in the laboratory on synthetic media, the necessary elements may be supplied in the following way:

1) Carbon is usually supplied in the form of a carbohydrate, such as glucose or maltose; sucrose and soluble starch are utilized by many fungi.

2) Nitrogen may be supplied in the form of ammonium (NH₄ ) salt or as amino acids. Many fungi can utilize nitrate (NO3) salts.

Generally these following media are used in laboratory for cultivation of fungi:

1 ) Czapek’s agar:

It is used for the subculture of Aspergillus species for their differential diagnosis. It contains sucrose as carbon-source and nitrate as the sole source of nitrogen, useful for the general cultivation of fungi, yeasts and soil bacteria.

2) Potato Dextrose Agar (PDA):
It is a relatively rich medium for growing a wide range of fungi. Many standard procedures use a specified amount of sterile tartaric acid (10%) to lower the pH of this medium to 3.5 + or - 0.1, inhibiting bacterial growth. 

Chloramphenicol acts as a selective agent to inhibit bacterial growth of competing microorganisms from mixed specimens, while permitting the selective isolation of fungi.

3) Sabouraud’s dextrose agar (SDA):

Sabouraud’s   Dextrose Agar (SDA) is a selective medium primarily used for the isolation of dermatophytes, other fungi and yeasts but can also grow filamentous bacteria such as Nocardia. The acidic pH of this medium (pH about 5.0) inhibits the growth of bacteria but permits the growth of yeasts and most filamentous fungi. Antibacterial agents can also be added to augment the antibacterial effect.

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"Cultivation of Fungi and Classification of Fungi"

Written By

Sadia Akhtar

Student of Department of Microbiology

Jagannath University.

Email- sadiabd810@yahoo.com