Cong T. Trinh:minimal medium E coli

Minimal medium for E. coli growth

Per litre

• 3.5 g KH2PO4
• 5 g K2HPO4
• 3.5 g (NH4)2HPO4
• 250 mg MgSO4 (or 2 ml of 1M MgSO4. Add 24.6 g MgSO4.7H20 in 100 mL water)
• 15 mg CaCl2.2H20 (or 100 uL of 1M CaCl2. Add 14.7 of CaCl2.2H2O in 100 mL water)
• 0.5 mg thiamine HCl (or 10 uL of 50 mg/mL)
• 1 mL stock trace metals solution
• X g sugars

Balance to 1L with deionized water or millipore water

Optional components

• Y g antibiotics
• Z g inhibitors
• pH adjustment
• Use either 40% H3PO4 or 5M KOH to adjust pH (pH6.5)
• Sterile filter the medium

Note: When preparing medium for bioreactor experiments, it is recommended to dissolve KH2PO4, K2HPO4, (NH4)2HPO4 first. CaCl2 should be added last and slowly while stirring. For preparation of small volume medium, we can prepare 5X solution containing KH2PO4, K2HPO4, (NH4)2HPO4. If concentrated stock solution is chosen, make sure it is well mixed before use.

• CaCl2 should be added last in dropwise manner while stirring. It is recommended to be added when the total volume reaches 900 mL and before pH adjustment.