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Starch Casein Agar (SCA) is a solid medium used for the detection of saccharolytic marine bacteria. It is also used for the cultivation and enumeration of Actinomycetes species from water and soil samples by the double-layer agar technique.
Composition of Starch Casein Agar (SCA)
Casein = 1 gm
Starch = 10 gm
Sea Water = 37 gm
Agar = 15 gm
Distilled Water = 1000 ml
pH = 7.2 +/- 2
Principle of Starch Casein Agar (SCA)
Casein supplies amino acids, peptides, vitamins and trace elements, while Starch is the source of carbohydrates. The salts of Seawater provide complex ionic sources that make the medium suitable for marine microorganisms and serve as buffering agents. Agar is the solidifying agent.
Preparation of Starch Casein Agar (SCA)
- Suspend 63.0 grams in distilled water.
- Heat to boiling to dissolve the medium completely.
- Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes.
- Cool to 45-50°C.
- Mix well and pour into sterile Petri plates.
Result Interpretation on Starch Casein Agar (SCA)
Figure: White Colonies of Actinomycetes on Starch Casein Agar (SCA)
Limitations of Starch Casein Agar (SCA)
- Due to nutritional variations, some strains may show poor growth on media.
- Further biochemical tests must be carried out for confirmation.