Dissolve ingredients and adjust pH to 2.0 with 10 N H2SO4.
Sterilize the medium by filtration. Alternatively, autoclave separately
the basal medium (pH adjusted to 2.0) and the ferrous sulfate (8.00 g FeSO4
x 7 H2O in 50 ml distilled water, pH not adjusted, in a sealed
vessel under nitrogen gas atmosphere). VTT E-991376: Omit the
ferrous sulfate from the medium and add 10.00 g / L elemental sulfur as
substrate. For sterilization place the sulfur in screw-capped tubes, add
1-2 drops of distilled water and incubate on 3 successive days for 3 h at
90-100°C in a water bath. Before use, aseptically layer the sulfur onto
the surface of autoclaved liquid basal medium, Adjust pH of completed
medium to 2.0.
