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To prepare the Nutrient Agar (solid)
and Nutrient Broth (Liquid) medium
A growth medium or culture medium is a solid or liquid or
semi-solid
designed
to
support
the
growth
of microorganisms or cells. The culture media are devised in
such a way that the organisms should get all the nutritional
requirements. Nutrient media contain all the elements that
most bacteria needed for growth and are not selective, so
they are used for the general cultivation and maintenance of
bacteria kept in laboratory culture collections. In Nutrient
media carbon source is glucose, beef extract as a source of
mineral salts, nitrogen, vitamins and peptone is semi
digested protein. Nutrient Broth medium is generally used for
cultivation of Bacteria. When a broth medium is supplemented
with agar- agar, it is called agar medium, for example
nutrient agar medium (NAM) for cultivation of bacteria. Agaragar is also called simply agar. Agar is product of marine red
algae such as Gelidium and Gracilaria.
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Nutrient Broth medium powder
Nutrient Agar medium powder
Distilled water
500 ml Conical Flask
Cotton plug
Composition of Nutrient Broth
 Peptic Digest of animal tissue: 5 gm
 Sodium chloride: 5 gm
 Beef Extract: 1.5 gm
 Yeast Extract: 1.5gm
 Distilled Water: upto 1000 ml
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Composition of Nutrient Agar
Peptic Digest of animal tissue: 5 gm
Sodium chloride: 5 gm
Beef Extract: 1.5 gm
Yeast Extract: 1.5gm
Agar: 15gm
Distilled Water: upto 1000 ml
A. Preparation of Nutrient Broth (Liquid
medium): 100ml
1. Weigh 1.3 gram of nutrient broth powder
and put it in a conical flask with a cotton
plug.
2. Measure 100 ml of distilled water in a
measuring cylinder and add in to conical
flask containing nutrient broth powder.
3. Dissolve the nutrient broth powder in the
water by swirling.
4. Autoclave it at 15 psi pressure in autoclave.
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B. Preparation of Nutrient Agar ( Solid
medium): 100ml
1. Weigh 2.8 gram of nutrient agar powder and
put it in a conical flask with a cotton plug.
2. Measure 100 ml of distilled water in a
measuring cylinder and add in to conical
flask containing nutrient agar powder.
3. Dissolve the nutrient agar powder in the
water by swirling.
4. Autoclave it at 15 psi pressure in autoclave.
1. Always use the distilled water for making the
media.
2. All the glassware should be properly
sterilized.