Isolation Of Bacteria

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Isolation of bacteria includes several techniques by which different bacterial colonies from a mixed culture can be separated. This isolation is important as it helps in studying the particular organism with its distinguished traits. Bacteria are in habit of living in an association with other organism/bacteria as this association will help in the better survival of an organism. These microbial populations will cooperate together and achieve better nutrients for each other because the waste of one may serve as a nutrient for the other. Similarly the waste from the metabolism of the one may provide the favourable condition to the other for growth.
These isolation techniques were developed by Robert Koch in 1883 in which he added agar to the liquid nutrient broth. With the addition of agar the liquid media was transformed into the solid media and helped in isolating different bacterial colonies. In this media the nutrient broth supplemented the nutrientinal requirements of the bacteria whereas agar provides the solid substrate for bacterial growth.
The pure culture contains a similar kind of bacteria that has risen from a single parent colony having similar cells. There are many methods by which pure cultures can be obtained a few are discussed below.
Serial dilution is a technique in which we find out the overall count of colonies present in the given sample. Serial dilution is followed by spread plate technique or the pour plate technique for the further isolation of microbes.
This procedure is applicable for finding out the total number of colonies from water and soil samples. The procedure includes the following steps.
• A set of 6 test tubes is taken which are then labelled as 1...

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...and will increase the number of the required selected colonies. The new cells which will form as a result of the reproduction of the old cells are called sub culture. This technique is of great importance as it is used to expand the number of cells as well increase the life expectancy of the selected microbes.
The bacteria can also be isolated by providing the selective media to a bacterial culture. Since the selective media can only support a specific group of microbes therefore by application of it the required group can be isolated from a non-requiring one. Specific materials are added to the culture plates which will prove as poison for non-requiring group ultimately inhibiting the further growth of those microbes. When these microbes will be eliminated then only required group will grow and survive which can then be isolated.

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