Laboratory microbial strain purification methods

First of all, the microbial suspension through a series of dilution, take a certain amount of dilution and melting good to keep at 40 ~ 50 ° about the nutrient agar medium fully mixed, and then this mixture is poured into the sterile Petri dishes, to be solidified, after the plate inverted in the constant box culture. A single cell after many proliferation to form a colony, take a single colony made of suspension, repeat the above steps several times, you can get a pure culture 2, coated plate method

First of all the microbial suspension through the appropriate dilution, take a certain amount of dilution on the sterile has been solidified nutrient agar plate, and then use a sterile glass spatula to the dilution of dilution evenly coated in the surface of the culture medium, through the constant temperature culture can be obtained. The constant temperature culture can get a single colony. 3, plate scribing method

The simplest method of separating microorganisms is the plate scribing method. With a sterile inoculation ring to take a little culture on the plate line. There are many methods of demarcation, and the common demarcation methods that are more likely to show single colonies are slanting line method, curve method, square method, radial method, four-frame method and so on. When the inoculation ring moves backward on the surface of the medium, the bacterial liquid on the inoculation ring is gradually diluted, and finally a single cell is scattered on the line drawn, and after cultivation, each cell grows into a colony.

4, enrichment culture method

Enrichment culture method and principle is very simple. We can create conditions that allow only the desired microorganisms to grow, and under these conditions, the desired microorganisms can effectively compete with other microorganisms, and far exceed other microorganisms in terms of growth capacity. The conditions created include the selection of optimum carbon source, energy source, temperature, light, pH, osmolarity and hydrogen receptors. The final enriched strains can easily grow single colonies on solid media after many repeated transplants in the same medium and culture conditions. If some specialized parasitic bacteria are to be isolated, it is necessary to inoculate the samples into the corresponding sensitive host cell populations and make them grow in large numbers. Pure parasitic bacteria can be obtained by repeated inoculation.

5, anaerobic method

In the laboratory, in order to isolate some anaerobic bacteria, can be used as a test tube containing the original medium as a culture vessel, the test tube in a boiling water 0 bath heated for a few minutes, in order to drive out of the dissolved oxygen in the medium. It is then cooled rapidly and inoculated. After inoculation, sterile paraffin is added to the surface of the medium to isolate the medium from air. Alternatively, after inoculation, N2 or CO2 is utilized to replace the gas in the medium, and then the mouth of the test tube is sealed over a flame. Sometimes, to isolate certain anaerobic bacteria more effectively, the isolated sample can be inoculated on the medium, and then the petri dish is placed in a completely sealed anaerobic incubator.