What are the types of culture media based on their use? Give an example

The purpose of culture medium is generally to cultivate and screen strains or identify, so it is divided into two categories:

1. Selective medium: a type of medium designed according to the special nutritional requirements of a microorganism or its resistance to a certain chemical and physical factors, which has the function of turning the inferior bacteria in the mixed bacterial sample into the dominant bacteria, and is widely used in the field of strain screening.

2. Identification medium: a kind of indicator that can react with the colorless metabolites of the target bacteria is added to the ingredients, so as to achieve the medium that can easily find out the colony of the target bacteria from the similar colonies by distinguishing the color with the naked eye. For example, eosin blue lactose medium (EMB).

Medium is differentiated by use:

1. Basal medium.

A medium containing essential nutrients for the growth and reproduction of microorganisms in general. Beef paste peptone.

Culture medium is the most commonly used basal medium.

2. Select the culture medium.

The medium designed according to the special nutritional requirements of a microorganism or its resistance to a certain chemical and physical factors has the function of turning the inferior bacteria in the mixed bacterial sample into the dominant bacteria, and is widely used in the field of strain screening.

3. Identification medium.

An indicator that can react with the colorless metabolites of the target bacteria is added to the ingredients, so that the medium of the target bacterial colony can be easily found from the similar colonies by simply distinguishing the color with the naked eye. For example, eosin blue lactose.

Culture medium (EMB).

According to the use, the medium can be divided into: basal medium, nutrient medium, identification medium, selection medium, and special medium.

Such as beef paste peptone cultivation base, wort cultivation base, glucose-ammonium salt cultivation base, starch nitrate cultivation base, potato sucrose cultivation base.

Classification by use includes: basal medium, proliferation medium, discrimination medium, 4Select the medium, Qingdao Haibo Biotech provides a variety of microbial culture media.

Selection of medium and identification medium.

According to the purpose of the medium: the medium can be divided into enrichment medium, selective medium and identification medium according to its special purpose.

1. According to its physical state, the medium can be divided into three categories: solid medium, liquid medium and semi-solid medium. (1) Solid medium. It is to add coagulants to the medium, including agar, gelatin, silica gel, etc.

Solid media are commonly used for microbial isolation, identification, enumeration, and culture preservation. (2) Semi-solid medium. It is a semi-solid state when a small amount of coagulant is added to the liquid medium.

It can be used to observe the movement of bacteria, identify bacterial species, and determine the potency of bacteriophages. (3) Liquid medium. No coagulant is added to the liquid medium.

The composition of this medium is uniform, and the microorganisms can fully contact and utilize the nutrients in the medium, which is suitable for physiological research. It is often used for microbial proliferation and enrichment. These media are commonly used in the fermentation industry.

2. According to the composition of the medium, it can be divided into three categories: synthetic medium, natural medium and semi-synthetic medium. (1) Synthetic medium. The various components are totally known various chemicals.

The chemistry of this medium is clear, the composition is precise, and the reproducibility is strong, and microorganisms grow slowly in this type of medium. It is generally used for the cultivation and identification of specific microorganisms. (2) Natural medium.

Made from natural substances such as steamed potatoes and regular beef broth, the former is used to grow mold and the latter is used to grow bacteria. The chemical composition of this type of medium is very unconstant and difficult to determine, but it is easy to prepare, rich in nutrients, and has a good cultivation effect. It is generally used for the proliferation and enrichment of microorganisms.

3) Semi-synthetic medium. Inorganic salts of known composition are appropriately added on the basis of natural organic matter, or some natural components are added on the basis of synthetic media, such as potato glucose agar medium for mold culture. These media are more effective at meeting the nutrient needs of microorganisms.

It is generally used for the proliferation and enrichment of specific classes of microorganisms. It is commonly used in strain breeding and industrial production.

1) Selective medium; A chemical is added to the medium to inhibit the growth of unwanted microorganisms and promote the growth of desired microorganisms.

2) identification medium; It is prepared by adding an indicator or chemical to the culture medium to identify different species of microorganisms.

3) enrichment medium; One or more nutrients are added to the basal medium, which promotes the growth of microorganisms in large numbers.

Houbai holdbio provides biological laboratory supplies and technical service support, and the general culture medium can be divided into the following categories:

Basal medium.

The version contains general bacterial growth and multiplication.

right to need basic nutrients. Basal medium is widely used in bacterial enhancement and testing. The most commonly used basal medium is beef paste peptone medium in natural media, which can be used as a base component in some special media.

Nutrient medium (enriched medium).

Certain special nutrients such as blood, serum, yeast extract or growth factors are added to the basal medium. Microorganisms that provide high nutrient requirements and require special growth factors.

Identification medium.

Using the ability of bacteria to decompose sugars and proteins and the difference in their metabolites, specific substrates and indicators are added to the culture medium to observe the different products released by the decomposition substrate during the growth of bacteria, and the bacteria are identified by the different reactions of the indicators. It is mainly used for the rapid identification of different types of microorganisms, such as lead acetate medium to check whether bacteria can produce hydrogen sulfide.

Select the medium.

The addition of inhibitors to the medium to inhibit the growth of bacteria in the specimen helps to increase the bacterial species of choice.

Anaerobic medium.

A medium for culturing obligate anaerobes.

Bacterial L-type medium.

A medium for L-type bacteria with cell wall defects.

HOLDBIO provides biological laboratory supplies and technical service support (HOBAY - cell biology reagents - cell culture).

Normal culture.

Base, for microorganisms without BAI special DU requirements.

Nutrient culture zhi base, which is used for microorganisms with nutritional requirements to select and return the nutrient base, selectively cultivate the required microbiological answers, inhibit the growth of other microorganisms, identify the medium, anaerobic medium for cultivating and distinguishing microbial species, and use for cultivating bacteria of anaerobic microorganisms.