Yeast extract 0.1 g Sucrose 5 g KH2PO4 0.4 g K2HPO4 0.1 g MgSO4.7H2O 0.2 g CaCl2.2H2O 0.02 g FeCl3.6H2O 0.01 g Na2MoO4.2H2O 0.002 g Bromthymol blue (0.5% in 0.2 mol/l KOH) 1 ml Agar 20 g Distilled water 1000 ml pH 6.8