Question

How to set up autoclave for nutrient broth and nutrient agar?

How to show that our bacteria produce H2S?

How do you isolate bacteria from surface and bentic zone from a river?

Answer 1

Ans) The nutrient broth and nutrient agar must be autoclaved before it is used as this helps in preventing contamination. For autoclaving, it is important to pour the nutrient agar or broth in glass bottles or test tube and cover it properly. It is important to use screw capped bottle for the nutrient broth and agar as it can keep the media intact and safe for longer time. The autoclave needs to be set at 121°C at 15 p.s.i for 15 minutes. This process around 90 minutes for the whole autoclave process to be completed and sterilization takes place.

Ans 2) there are different test that can be undertaken to show that the bacteria produce H2S or hydrogen sulphide. This is called H2S production test and helps in determining if the bacteria is able to reduce the sulfur containing compounds. If it produces the sulphide, it combines with Fe, it produces black precipitate FeS.