Thiosulphate Agar is used for cultivation of sulphur metabolizing bacteria present in soil specimens. Desulfovibrio desulfuricans is a species of sulphate-reducing bacteria that reduce inorganic sulphate into hydrogen sulphide. Sodium thiosulphate, Dipotassium hydrogen phosphate, Sodium bicarbonate, Ammonium chloride salts in the medium fulfills ion requirement of bacteria.