• Yeast extract 0.30 g
• Ethanol 0.50 ml
• Na₂-succinate 1.00 g
• (NH₄)-acetate 0.50 g
• Fe III citrate solution (0.1% w/v in water) 5.00 ml
• KH₂PO₄ 0.50 g
• MgSO₄·7H₂O 0.40 g
• NaCl 0.40 g
• NH₄Cl 0.40 g
• CaCl₂·2H₂O 0.05 g
• B₁₂ vitamin solution (10 mg in 100 ml of water) 1 ml
• Trace elements solution SL-6 1 ml
• Distilled water up to 1 L

Adjust pH to 6.8. Distribute the medium in 12-15 ml tubes with screw cap. Fill the tubes up to 1 cm from the top. Autoclave them at 121°C for 20 min with the cap slightly open. Fill the tubes completely, add 0.01 ml of 0.50% sterile cysteine and close inmediatly after autoclaving.

Trace elements solution SL-6

• ZnSO₄·7H₂O 0.10 g
• MnCl₂·4H₂O 0.03 g
• H₃BO₃ 0.30 g
• CoCl₂·2H₂O 0.20 g
• CuCl₂·2H₂O 0.10 g
• NiCl₂·6H₂O 0.02 g
• Na₂MoO₄·2H₂O 0.03 g
• Distilled water 1 L