Chemical Composition of Starch Casein Agar

In this chemical composition of starch casein agar post we have briefly explained about starch casein agar principle, starch casein agar composition, appearances, storage, preparation, result, applications, and limitations of starch casein agar.

Starch Casein Agar

The saccharolytic marine bacteria and predominantly actinomycetes are detected using SCA. Actinomycetes are bacteria that resemble mushrooms and develop long filaments that strew through the soil. They are a major gram-positive filamentous or branching Bacillus group. Although the first report of mycelium-forming actinomycetes being recovered from sea sediments came several decades ago, actinomycetes have been isolated from terrestrial sources.

Marine sediments have been identified as a source of novel antibiotics and anticancer medicines, as well as a possible source of novel actinomycetes providing new products. By digesting and converting a wide range of complex organic wastes, actinomycetes have a large impact on the environment. As a result, actinomycetes are an important category of bacteria found in the environment, and they play a vital role not only in medicinal applications but also in organic waste recycling.


The complex carbohydrate supply in this medium is starch, while the nitrogen source is casein. Seawater salts provide complex ionic sources, making the media ideal for marine microbial flora while also buffering it.

Chemical Composition of Starch Casein Agar


1. Soluble starch: 10.00,

2. Casein (Vitamin Free): 0.30,

3. KNO3: 2.00,

4. MgSO4.7H2O:0.05,

5. K2HPO4 :2.00,

6. NaCl: 2.00,

7. CaCO3: 0.02,

8. FeSO4.7H2O: 0.01,

9. Agar:18.00.

Media Preparation

1. Casein Powder: 1.0,

2. Starch: 10.0,

3. Sea Water: 37.0,

4. Agar: 15.0,

5. Final pH (at 25°C) 7.2 ± 0.2.

Plate Preparation

Suspend 63.00 g of the starch casein agar in 1000 mL distilled water. Heat to boiling to dissolve the starch casein agar completely. Sterilize by autoclaving at 121°C (15 psi) for 15 minutes as per validated cycle. Mix well and pour starch casein agar into sterile Petri plates.


Starch Casein Agar

Interpretation: Off-white to yellow colored homogeneous free flowing powder.


Starch casein agar is recommended for detection of saccharolytic marine bacteria. Actinomycetes are free living, saprophytic, filamentous bacteria, and a major source for the production of antibiotics. They are found in soil, fresh water and marine water environments.

Further Readings