Why is the liquid medium powdered?
medium(Medium) is an artificially prepared nutrient for the growth and maintenance of microorganisms, plant tissues and animal tissues. Generally, it contains carbohydrates, nitrogen-containing substances, inorganic salts (including trace elements), vitamins and water. Different types can add some compounds that cannot be synthesized by themselves according to actual needs, namely growth factors.
Why is the liquid medium powdered?
Due to the different raw materials prepared, the requirements for use are different, and the storage and storage are also slightly different. Generally, after being heated and moisture-absorbing, it is easy to be contaminated by bacteria or decomposed and deteriorated, so it must be stored in a moisture-proof, dark and cool place. For some media that require strict sterilization, long-term storage must be placed in a refrigerator at 3-6 ° C. Since liquid media is not easy to store for a long time, they are all converted into powder.
According to the physical properties of the medium, the medium is divided into:
1. Liquid medium
80% to 90% water, medium with soluble or insoluble nutrients. The liquid is to obtain a large number of cells or cell products
2. Solid medium
A type of prepared solid state substrate. Generally used to cultivate colonies or animal and plant tissues.
Add about 2% agar to the liquid medium, heat it to 100 ° C to dissolve, cool it at 40 ° C and solidify it to make it a solid state, which is the solid medium.
3. Semi-solid medium
Refers to a semi-solid medium prepared by adding a small amount of coagulant to the liquid medium.
Selection of medium:
The same formula often has some differences in different works. Therefore, in addition to the standard method used, it should be strictly prepared according to its provisions. Generally, relevant information should be collected as much as possible, compared and checked, and then selected according to their own purpose of use, recording its source.
