Isolation of Pure Culture

Isolation of Pure Culture :

As we know the environment is full of mixed of all organisms lives in mixed population means several species are grow in nature simultaneously along with each other in Nature.

But what to do when need to isolate pure culture or desired organism in this case we need to only specific single cell or individual characterized culture.

Robert Koch introduced the solution of this problem to acquired pure culture technique by the following techniques we can get the pure isolated colony by the following techniques -

1) Spread Plate Technique

2) Streak Plate Technique

3) Pour Plate Technique

                   Julius Richard Petri

Julius Richard Petri inventor of special dishes which are known as Petri Dish/Petri Plate in 1887 who invented these special culture plate.

                Petri Dish or Petri Plate

Julius Richard Petri was a German microbiologist who is generally credited with inventing the device known as the Petri dish, which is named after him, while working as assistant to bacteriologist Robert Koch.

1) Spread Plate Technique :

In this technique mixed culture cells is spreaded on agar surface to allow every individual cell to grow into a separate colony.

Each single colony represents a pure culture a very small volume of approximately 30-300 mixed cells culture transfer to center of the plate and spread it evenly by sterile glass-bent rod aseptically.

2) Streak Plate Technique :

In this technique which is totally based on streaking the microbial culture or mixed microbial culture is transfered to the top edge surface of the agar plate with the help of sterilized inoculating loop also known as Nichrome wireloop or swab which help streak out over on the surface by several patterns to obtained the pure isolated colony.

3) Pour Plate Technique :

The pour plate technique is the only technique which extensively used to get the isolated Bacterial Colony & Fungal Colony in this technique sample is diluted many times which called Folds or serial dilutions.

The reduced microbial population to obtained separate colony when plating after this the diluted or reduced populated microbes are mixed with molten agar and cooled down at 45°C and pour into petri dish.

As this poured technique consisting two halves one half is on the top and another half on bottom which are overlapped which allows bacterium to replicates to firm colonies which will be vusible upto 109 copies of original bacteria.