Culture Media and Requirements for Growth A large number of undemanding microorganisms, for example many pseudomonads in soil and water, and also Escherechia coli thrive in culture solutions according to their composition. Apart from their growth structure, many microorganisms still require other elements, namely complementary elements, vitamins and other additional compound elements. A culture solution that can be made from certain chemical compounds is called a synthetic culture medium.Typically, the culture medium contains water, an energy source, nutrients as a source of carbon, nitrogen, sulfur, phosphate, oxygen, hydrogen and trace elements. The media is divided into 2 large groups, namely: • Live media Live mediagenerally used in virology laboratories for culturing various viruses, whereas in bacteriology only certain types of germs and especially experimental animals. Examples of living media include: experimental animals (including humans), embryonated eggs, tissue culture, and certain bacterial culture cells for bacteriophages. • Media is off • Based on the consistency of solid media, media are divided into slanted, deep, for example: Buylon agar, Endo agar, SS agar, and so on. Semi-solid media: semi-solid buylon agar (buylon=broth). Liquid media: buylon water, peptone water, sugar series. Solid media is obtained by adding agar. Agar derived from algae is used as a solidifying agent because it is not broken down by microbes, and solidifies at temperatures above 45o C. Media semi-solid is used to see the movement of germs microscopically. • Based on the composition or composition of the ingredients a. Synthetic media Synthetic media is media that has ingredients and contents that are known in detail. Synthetic media are often used to study the physiology and genetics of microorganisms. The inorganic and organic compounds added in synthetic media must be pure, so they are expensive. Examples: Hanks, Locke, Thyrode, Eagle fluids. In (virology laboratory). b. Non-synthetic media is media that contains ingredients whose content and composition are not known with certainty. Examples: meat extract, peptone, yeast extract, meat broth. Often blood, serum, vitamins, amino acids, or nucleosides are added to this medium. c. Semi-synthetic media For example, Hanks fluid to which serum is added (virology laboratory). • Based on physiological and biological propertiesgerms and for isolation purposes a. Nutrient media is a medium that is very rich in nutrients and has a composition of ingredients in such a way that it only fertilizes one type of germ that is sought. Example: Kauffmann seeds for nursery Salmonella typhi. b. Exclusive media is media that only allows the growth of one type of germ, while others are inhibited or killed. Example: Dieudoune seeds or alkaline peptone water which has a high pH so that other germs cannot grow, except Vibrio. c. Selective media is media that has a composition of materials in such a way that certain germs can grow but with each colony being very unique. Example: endo agar, for coli group bacteria (coliform) will be red, while Salmonella colonies are colorless