Growth Media
| Contents |
|---|
| Czapek's Agar (CZA) |
| Hay infusion agar |
| Malt Extract Agar (MEA) |
| Modified Dixon's agar (mDixon) |
| Potato Dextrose Agar (PDA) |
| Sabouraud agar or Sabouraud's dextrose agar (SDA) |
Czapek's Agar (CZA)
Applications
Czapek's agar is used for cultivation of fungi and certain other organisms.
The medium contains:
- sucrose (energy and carbon source)
- sodium nitrate (nitrogen source)
- dipotassium phosphate (K2PO4) (buffering agent)
- magnesium sulfat (MgSO4)
- potassium chloride (KCl)
- ferrous sulfate (FeSO4)
- agar (gelifying agent)
- H2O
The pH of the medium should be 7.3.
Other comments:
This medium is recommended for growing Aspergillus spp. Penicillium spp. and Paecilomyces spp. As well as some other fungi. Only organisms that can use nitrate (NO3-) as a source of nitrogen can grow on this medium.
Updated: 2022-02-03.
ContentsHay infusion agar
Applications
Hay infusion agar is a nutrient deficient medium, which can be used for subcultivation of fungi (for instance Actinomortierella wolfii), to get them to sporulate.
The medium contains:
- partially decomposed hay
- di-potassium hydrogen phosphate (K2HPO4)
- agar (solidfying agent)
- H2O
The final pH of the medium should be 6.2.
Updated: 2021-01-14.
ContentsMalt Extract Agar (MEA)
Applications
Malt extract agar (MEA) is used for cultivation of yeasts and moulds.
Content of the medium:
- malt extract
- agar (gelifying agent)
- water
The pH of the medium should be 4.7.
Other comments:
The high concentration of maltose makes this medium particularly useful for cultivation of yeasts and moulds.
Updated: 2022-02-03.
ContentsModified Dixon's agar (mDixon)
Applications:
Dixon's agar is mainly used for growing Malassezia furfur, but a modified variant (mDixon) can also be used for growing other dermatophytes.
The medium contains:
- malt extract (contains nutrients)
- peptone (enzymatic degradation products of animal tissue or milk, which are also a sources of various nutrients)
- desiccated beef bile, which contains various bile acids
- Tween 40
- glycerol monooleat, which is a source of oleic acid
- agar (gelifying agent)
- H2O
The pH of the medium should be 6.0.
Other comments:
Most Malassezia species (except M. pachydermatis) are lipophilic i.e. they require the addition of lipids to the culture medium. Other dermatophytes can also be grown in mDixon.
Updated: 2021-09-16.
ContentsPotato Dextrose Agar (PDA)
Applications
Malt extract agar is used for cultivation of yeasts and moulds.
Content of the medium:
- potato infusion
- dextrose
- agar (gelifying agent)
- water
The pH of the medium should be 5.6.
Other comments:
The medium can be supplementet with acid and/or antibiotics to inhibit bacterial growth.
Updated: 2022-02-03.
ContentsSabouraud agar or Sabouraud's dextrose agar (SDA)
Image A shows a plate containing Sabouraud Agar before cultivation. Image B shows the same kind of plate on which Hanseniaspora uvarum has been cultivated at 30°C during 5 days. - Click on the image to enlarge it (opens in a new window/tab).
Image: Ingrid Hansson (BVF,SLU), Lise-Lotte Fernström (BVF, SLU) and Karl-Erik Johansson (BVF, SLU).
Use
Sabouraud agar is mainly used to grow dermatophytes and other types of yeasts and molds. Sabaroudagar can also be used to grow filamentous bacteria, e.g. species within the genus Nocardia.
The medium contains:
- dextrose (which is another name for D-glucose)
- peptone (hydrolyzed proteins, which contains short peptodes and amino acids)
- agar (jelly-forming substance)
The pH of the medium should be 5.6 and this relatively low pH inhibits the growth of many bacteria.
Other comments
This medium is not always recommended for primary isolation, as it is not nutritious enough for some fastidious fungi. This is especially true for many of the dimorphic fungi.
Updated: 2021-05-14.
Contents