N/20 Medium



N/20 Medium Recipe

Directions 
The final medium is prepared on a tube by tube basis, using 15 mL glass tubes, stoppered with rubber-lined screw caps.

For 1 L Total

1. To approximately 850 mL of dH2O, add each of the components in the order specified (except vitamins) while stirring continuously.
2. Bring the total volume to 1 L with dH2O.
3. Cover and autoclave medium.
4. When cooled add vitamins.
5. Store at refrigerator temperature.

# Component Amount Stock Solution
Concentration
Final Concentration
1 KH2PO4 (Sigma P 0662) 2 mL/L 17.5 g/200 mL dH2O 1.29 mM
2 NaNO3 (Fisher BP360-500) 100 µL/L 25 g/200 mL dH2O 0.14 mM
3 K2HPO4 (Sigma P 3786) 1 mL/L 15 g/200 mL dH2O 0.43 mM
4 NaCl (Fisher S271-500) 1 mL/L 5 g/200 mL dH2O 0.43 mM
5 CaCl2·2H2O (Sigma C-3881) 1 mL/L 5 g/200 mL dH2O 0.17 mM
6 MgSO4·7H2O (Sigma 230391) 1 mL/L 15 g/200 mL dH2O 0.3 mM
7 P-IV Metal Solution 6 mL/L    
8 Sodium acetate (Fisher BP 333) 0.67 g/L   8.12 mM
9 TES buffer (Sigma T 1375) 0.92 g/L   4.01 mM
10 Vitamin B12 1 mL/L    
11 Thiamine Vitamin Solution 1 mL/L