Question

When seeking to isolate the genus Rhizobium, what specific conditions (in terms of media components) would limit the growth of other bacteria while enriching for the growth of the genus Rhizobium? Be as specific as possible and explain.

Answer 1

For growing of genus Rhizobium bacteria- YEMA(Yeast and Mannitol) broth can be used and for isolation and purification purposes of Rhizobium- YEMA agar can be used, this is due to the fact that YEMA is a differential medium to differentiate Rhizobium (colourless, glistening colonies) from other colonies of bacteria.

The general components are as follows

Yeast Mannitol Agar

1 g yeast extract

4 g mannitol

0.5 g dipotassium phosphate

0.2 g magnesium sulphate

0.1 g sodium chloride

15 g agar

1 l water

Autoclave for 15 minutes at 121degree Celsius and 15 Psi

Yeast Mannitol Broth

1 g yeast extract

4 g mannitol

0.5 g dipotassium phosphate

0.2 g magnesium sulphate

0.1 g sodium chloride

1 l water

Autoclave for 15 minutes at 121degree Celsius and 15 Psi