Both liquid culture and solid culture are possible, and the main limiting factor is oxygen. Ordinary plate culture (solid) and shake flask culture (liquid) can be used in the laboratory. In order to increase the supply of oxygen, various forms of ventilation and stirring can be carried out. Shallow liquid culture (without shaking) is also aerobic culture.

I. separation of solid culture medium

1, dilution dumping plate

Features: The colony separation is relatively uniform, and the microbial count results are relatively accurate. However, the operation is relatively troublesome, heat-sensitive bacteria are sometimes easy to burn to death, and strict aerobic bacteria fixed in the culture medium may also be affected.

2, coating plate method

Features: The operation is relatively simple, and it is a common routine method. But sometimes the colonies in some parts can't be separated because of uneven coating, so we should pay special attention to the operation of dilution and coating process when counting microorganisms, otherwise it is not easy to get accurate results.

3, flat line method

Features: Simple operation, mostly used for the confirmation and re-separation of existing pure cultures.

Application: These three methods can be used for the pure culture and separation of all microorganisms that can form colonies on the surface of solid medium. In addition, by selecting suitable selection plates and culture conditions, various microorganisms with specific physiological characteristics can be directly separated. Combined with anaerobic tank or anaerobic glove box technology, these three methods can also be used to obtain pure cultures of various anaerobic bacteria.

4, dilution shake tube method

Features: an improved form of dilution inverted plate method, but because colonies form in the middle of agar column, it is relatively difficult to observe and select.

Application: In the absence of professional anaerobic operation equipment, strict anaerobic bacteria separation and observation are carried out.

Secondly, separating the liquid culture medium.

1, dilution method

Features: The workload is heavy, and whether pure culture can be obtained depends on statistical speculation.

Application: Pure culture, separation or quantitative statistics of microorganisms that cannot or are not easy to grow on solid medium.

2. Proliferation culture

Characteristics: It is generally impossible to directly obtain the pure culture of microorganisms. In the natural environment, a small number of microorganisms have increased greatly through enrichment culture, so it is necessary to separate and detect the corresponding pure cultures of microorganisms by plate method. Application:

(1) According to the special growth requirements of a microorganism, the microorganism is effectively separated from nature;

(2) Isolation and culture of microorganisms that can grow in a specific environment designed by scientists, although we don't know what microorganisms can grow in this specific environment.

Third, micro-operation.

Single cell (spore) picking

Features: The separation process is intuitive and reliable, but it requires high instruments and operation technology, and is mostly limited to highly specialized scientific research. However, the single cell or spore of the selected microorganism needs to be cultured in solid or liquid medium to obtain its pure culture. Application: Directly separate the required microbial cells or spores from the sample to obtain its pure culture.