Czapek medium (also known as Czapek’s agar or Czapek Dox medium) is a medium used to grow fungi and other organisms. This medium is suitable for qualitative cultivation of soil bacteria and saprophytic fungi. Czapek originally created the medium in 1902 to cultivate saprophytic mushrooms. Czapek-Dox Agar, a modified formula of the Czapek (1902-1903) and Dox (1910) formulas, is prepared according to Thom & Church. Medium contains sucrose as the only source of carbon, and nitrate is the only inorganic nitrogen source.
Principle of Czapek’s Agar (CZA)
Czapek Medium, a neutral, solid medium that contains only sodium nitrate, is the sole source for nitrogen. This inorganic nitrogen source can be used by bacteria and fungi. Sucrose is a source of energy and the only source of carbon. Dipotassiumphosphate acts as a buffering agent. Potassium chloride has essential ions. Magnesium sulfate, ferrous sulfate, and potassium chloride are all sources of cations.
Composition of Czapek’s Agar (CZA)
| Ingredients | Gms/liter |
| Sucrose | 30.000 |
| Sodium nitrate | 2.000 |
| Dipotassium phosphate | 1.000 |
| Magnesium sulfate | 0.500 |
| Potassium chloride | 0.500 |
| Ferrous sulfate | 0.010 |
| Agar | 15.000 |
Final pH (at 25°C) 7.3±0.2
Preparation and Method of Use of Czapek’s Agar (CZA)
- In 1000 ml of distilled water, you can suspend 49.01 grams
- To dissolve the medium completely, heat to boiling
- For 15 minutes, sterilize by using an autoclave at 15 lbs pressure (121degC).
- Keep it at 45-50 degrees Celsius
- Mix everything together and pour onto sterilized Petri dishes.
- You can inoculate the material by spreading thinly the sample on top of the agar medium.
- For 1 to 2 weeks, incubate aerobically at 25-30degC.
- Regularly examine the plate for signs of growth.
- Each colony type should be subcultured to the appropriate media for isolation. Following established laboratory procedures, identify each colony type.
Pour Tube: Heat the pour tube in a saucepan of boiling water and let it cool to 45-50°C. Mix the ingredients and pour into a sterilized petri dish. Follow the instructions.
Result Interpretation of Czapek’s Agar (CZA)
| Organisms | Growth |
| Aspergillus brasiliensis | Good growth |
| Candida albicans | Good growth; cream-colored colonies |
| Saccharomyces cerevisiae | Good growth |
| Aspergillus niger | White/yellow mycelium, black spores |
Uses of Czapek’s Agar (CZA)
- APHA recommends Czapek Dox Agar for isolating Aspergillus and Penicillium.
- Standard Methods of Examination of Water and Wastewater recommends Czapek Medium for the isolation of Aspergillus and Penicillium.
- This medium is used extensively for taxonomic studies on Penicillium.
- Czapek Agar is able to grow nearly all saprophytic aspergilli vigorously and produces distinctive mycelia and conidia.
- For the cultivation of acidophilic organisms like yeasts, the acidity of the medium can be increased.
- This medium can be used in a wide range of microbiological procedures including soil microbiology testing and fungi and mildew resistance testing.
Limitations of Czapek’s Agar (CZA)
- This medium is general-purpose and does not support fastidious organisms.
- For complete identification, it is recommended that colonies grown from pure culture be subject to biochemical, immunological and molecular testing.
