Question

Explain how the sterilization of the growth media is achieved in the laboratory.

Hint:

Remember the different methods of sterilisation, and the principles on which they work.

Answer 1

Autoclaving: Autoclaving is a common method for sterilizing growth media. The media is heated to a high temperature (usually 121°C) under high pressure (15 psi) for 15-20 minutes in an autoclave. This ensures that microbes and spores are killed in the growth media. 

Membrane Filter Sterilization: Another common method involves filtering the media with a membrane filter. Here, the media is forced through a membrane with a very fine pore size (0.2 or 0.22 micrometer pore size). This process physically removes microbes from the media, making it sterile for use in the lab.