Synthetic Media (chemically defined media)
* These media are also called as chemically defined media because exact chemical composition of these media is known. They are made up of the compound of known chemical composition.
* As the exact chemical nature of all the ingredients is known, it is possible to duplicate the same medium to a high degree of accuracy.
* They have special uses in research and industry.
* These are empolyed where it is desired to know the effect of certain compounds on an organisms.
* These are artificial media of exactly known, reproducible composition and hence called synthetic or chemically defined media.
* For example, a defined medium used for Thiobacillus thiooxidans is as follows :
CaCl2 0.25g
KH2PO4 2g
(NH4)2SO4 3.0g
MgSO4 0.5g
Sulfur powder 10.0g
Distilled water 1000ml
This provides all the needed elements and a source of energy. KH2PO4 serves as a buffer for maintaining the suitable pH. It also serves as source of phosphorous and potassium. The powdered sulfur is a source of energy. It is oxidised to H2SO4. Carbon is obtained as CO2 from atmosphere. Nitrogen is provided by ammonium salt from this simple solution the organisms is able to synthesize proteins, carbohydrates, DNA, RNA, etc.
Application :
1. To know the effect of certain compound on an organisms.
2. To determine nutritional requirements of bacteria.
3. To study metabolism of certain compounds in an organism.