over view on culture media

An appropriate culture media is needed for the proper growth and maintenance of a microorganism that is done in the laboratory. These specialized culture media are important in the identification and isolation of microorganism. Each microorganism varies in terms of their needs, such as energy, carbon, nitrogen, phosphorus, sulfur, and various minerals that they acquired in their specific culture media. It is necessary to have knowledge in identifying the normal habitat of microorganism so that it would be easier in selecting specific culture media that is suitable for them.  

Complex media is composed of peptones, meat extract and yeast extract. A partial proteolytic digestion of meat, casein, soya meal, gelatin, and other protein sources produces protein hydrolysates called peptones. Meat extract contains amino acids, peptides, nucleotides, organic acids, vitamins, and minerals. Both meat and yeast extract are aqueous extracts of élan beef and brewer’s yeast. They serve as sources of carbon, energy, and nitrogen.

 Selective media favor the growth of particular microorganisms. Bile salts or dyes like basic fuschin and crystal violet favor the growth of gram negative bacteria by inhibiting the growth of gram positive bacteria without affecting the gram negative organisms. Endo agar, eosin methylene blue agar, and Mac Conkey agar are wisely used for the detection of E. coli.