Nutrient agar

Nutrient agar is a microbiological growth medium commonly used for the routine cultivation of non-fastidious bacteria. It is useful because it remains solid even at relatively high temperatures. Also, bacteria grown in nutrient agar grows on the surface, and is clearly visible as small colonies. In nutrient broth, the bacteria grows in the liquid, and is seen as a soupy substance, not as clearly distinguishable clumps. Nutrient agar typically contains (w/v):^[1]

• 0.5 % Peptone
• 0.3 % beef extract/yeast extract
• 1.5 % agar
• 0.5% NaCl

distilled water

• pH adjusted to neutral (6.8) at 25 °C.

Nutrient broth is made identically, except omitting the agar.

References