Purpose of Isolation and Purification of Microorganisms

The process of isolation and purification is to obtain only one type or strain of microorganism from a mixed microbial population. In some bacterial assays, we often need to isolate and purify a particular target bacterium because multiple species are often present in the sample. Through isolation and purification, we are able to evaluate the microbiological data of the specimen, which is often used for contamination identification, active substance testing, product quality parameter evaluation, etc. Therefore, it is essential to understand the isolation and purification of microorganisms.

Principle of Microbial Isolation and Purification

A microbial culture containing more than one type of microorganism is called a mixed culture. If all cells in a colony are derived from one parental cell, then the colony is called a pure culture. The purpose of microbial isolation and purification is to separate the target bacteria from the mixed microorganisms and obtain a pure culture.

Microbial Isolation and Purification Methods Offered by Creative Biogene

Creative Biogene offers a wide range of microbial isolation and purification methods for different microorganisms. The selection of the specific method can be based on the type of sample, strain properties, and research needs of the customer to help them obtain pure cultures of microorganisms.

• Pour plate method

Put the microbial suspension through a series of dilutions, and add the diluted sample to the sterile medium and mix well. After waiting for solidification and inverting the culture, a single cell is proliferated several times to form a colony, a single colony is taken to make a suspension, and the above steps are repeated several times to obtain a pure culture.

• Coating plate method

Transfer a certain concentration and volume of the bacteria to be isolated to the solidified medium plate, and then use the applicator stick to quickly spread it evenly, so that a single colony grows and achieves the purpose of isolation.

• Plate scribing method

A small amount of culture is taken with a sterile inoculation loop and scribed on the plate. The common scribing methods are diagonal method, curve method, square method, radiation method, four-grid method, etc.

• Enrichment culture method

We can create conditions in which only the desired microorganisms grow, and in which the desired microorganisms can effectively compete with other microorganisms and far outperform them in terms of growth capacity. If some specialized parasitic bacteria are to be isolated, it is necessary to inoculate the sample into the corresponding sensitive host cell population to grow them in large numbers. Pure parasitic bacteria can be obtained by several repeated grafts.

• Anaerobic method

To isolate certain anaerobic bacteria, the isolated samples were inoculated on a culture medium before the petri dishes were placed in a completely sealed anaerobic culture unit.

• Single cell isolation method

Pure cultures were obtained by directly isolating individual cells from the material to be isolated for culture.