UTEX sells Bold Basal Medium at 1X concentration only. Stock solutions and individual components for this specific medium are currently not available for purchase.

Bold Basal Medium

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Bold Basal Medium


For 1 L Total
  1. To approximately 900 mL of dH2O add each of the components in the order specified into a 1-Liter graduated cylinder.
  2. Add one drop of each of the following solutions to the cylinder. [One drop equals approximately 0.05 mL.]
    • EDTA Stock
    • Iron Stock
    • Boron Stock
    • Bold Trace Stock
  3. Bring the total volume to 1L with dH2O.
  4. Transfer to a 2-Liter Erlenmeyer flask. Cover the flask with aluminum foil and an inverted beaker.
  5. Autoclave to sterilize; allow to cool.
  6. Use aseptic technique to dispense media into separate sterile receptacles as required.

# Component Amount Stock Solution Concentration Final Concentration
1 NaNO3 (Fisher BP360-500) 10 mL/L 10 g/400mL dH2O 2.94 mM
2 CaCl22H2O (Sigma C-3881) 10 mL/L 1 g/400mL dH2O 0.17 mM
3 MgSO47H2O (Sigma 230391) 10 mL/L 3 g/400mL dH2O 0.3 mM
4 K2HPO4 (Sigma P 3786) 10 mL/L 3 g/400mL dH2O 0.43 mM
5 KH2PO4 (Sigma P 0662) 10 mL/L 7 g/400mL dH2O 1.29 mM
6 NaCl (Fisher S271-500) 10 mL/L 1 g/400mL dH2O 0.43 mM
7 EDTA Stock 1 drop
(0.05 mL)
8 Iron Stock 1 drop
(0.05 mL)
9 Boron Stock 1 drop
(0.05 mL)
10 Bold Trace Stock 1 drop
(0.05 mL)

Important Notes To Consider:

  • The quality of water, including natural seawater, is important. The term 'dH2O' generally refers to distilled, deionized, distilled/deionized water, Milli-Q water (Millipore Corp.), etc. Natural seawater and natural freshwater should be obtained from a non-polluted source.
  • When dissolving chemicals, wait for the first component to dissolve before adding the second. Stirring, and sometimes the addition of heat, is often required to dissolve the chemicals efficiently. Preparation of stock solutions for frequently made algal culture media make preparing media convenient but also necessary to avoid errors from weighing very tiny amounts.
  • Attention should be given to the pH of the final medium. In most cases, if pH adjustment is required, this occurs before sterilization. Please note that autoclaving removes carbon dioxide from media lacking carbonate stabilizing buffers. This would make the medium very alkaline soon after removal from the autoclave. In these cases, you should wait approximately 24 hours for gaseous equilibrium before inoculating the medium.