The document discusses various common components used in bacteriological media, such as peptones, beef extract, yeast extract, and agar, emphasizing their roles in providing essential nutrients for microbial growth. It also highlights different types of media, including nutrient agar and nutrient broth, as well as the physical conditions needed for growth such as temperature and pH. Additionally, the document mentions the classification of cultural media into selective or enriched and differential types.

1. Bacteriological Media
by,
Miss Areesha Ahmad
Lecturer Microbiology
B.Sc (H), M.Sc, M.Phil and Ph.D scholar (Microbiology)

2. Common ingredients

3. Peptone
Peptones are protein hydrolysates formed by enzymatic or acidic digestion of various raw materials and
many complex media contain peptones as the source of nitrogen.

4. Beef extract
The beef extract is the primary source of carbon which is essential for the formation of carbohydrates in the
bacteria. It also contains other components like some vitamins, different trace minerals, organic compounds, and
salts, which further enhance the growth of different organisms.

5. Yeast extract
Yeast extract is a complex and widely used hydrolysate of yeasts. It provides nitrogenous compounds, carbon,
sulfur, trace nutrients, vitamin B complex and other important growth factors, which are essential for the growth
of diverse microorganisms.

6. Agar
· It is one of the principle ingredients in the preparation of solid or semisolid media.
· It is used as a solidifying agent in culture medium.
· It is extracted from certain seaweeds belonging to genera of red algae like Gelidium and Gracilaria (Figure 5.1).

7. Nutrient agar
Nutrient agar is a general purpose medium supporting growth of a
wide range of non-fastidious organisms.

8. Nutrient broth
Nutrient broth is the nutrient agar that lack of the solidifying agent,
agar powder. They remain in liquid form at room temperature and are
usually used to maintain the stocks of microorganisms. In general, they
are used to grow fastidious organisms.

9. Types of Media

10. Selective or enriched media

11. Differential Media

12. Classification of Cultural Media

13. Media Preparation

14. Physical condition required for growth on
media

15. Temperature

16. pH
• Acidic 1-6 fungi
• Neutral 7 bacteria
• Alkaline8-14

17. Gaseous requirement

18. Thankyou...