WC medium concentrate

*This formulation has been modified from the original.

Reference: Andersen, R. A. (Ed.). (2005). Algal culturing techniques. Academic press.

This concentrate is used for many freshwater chrysophytes, cryptophytes, dinoflagellates, and some diatoms. WC may be one of the most well-rounded (least selective) types of medium.

WC primary concentrate

Stock Substance Stock solution (g/L) Volume used to prepare 200 mL of primary concentrate Concentration in primary concentrate (g/L) Final concentration in medium (mg/L) (adding 20 mL/L)
  Purified H2O – 70 mL – –
1. CaCl2•2H2O 36.76 10 mL 1.838 36.76
2. MgSO4•7H2O 36.97 10 mL 1.8485 36.97
3. NaHCO3 12.6 –a –a 12.6
4. Na2SiO3•9H2O 28.42 –a –a 28.42
5. Ca(NO3)2•4H2O 4.13 50 mL 1.0325 20.65
6. NH4NO3 10 40 mL 2.0 40
7. K2HPO4 8.71 –a –a 8.71
8. Trace metal solution See below for concentrations 10 mL See below for concentrations See below for concentrations
9. f/2 vitamin solution See below for concentrations 10 mL See below for concentrations See below for concentrations

aNOTE: WC Stock solutions 3, 4, and 7 that are normally added to WC medium are removed from the primary concentrate as they precipitate out. However, these stocks can be combined together as a secondary concentrate as per the following table and added separately during preparation of the medium.

WC secondary concentrate

Stock Subtance Stock solution (g/L) Volume used to prepare 50 mL of secondary concentrate Concentration in secondary concentrate (g/L) Final concentration in medium (mg/L) (adding 5 mL/L)
  Purified H2O –  20 mL –  – 
3. NaHCO3 12.6 10 mL 2.52 12.6
4. Na2Si3•9H2O 28.42 10 mL 5.684 28.42
7. K2HPO4 8.71 10 mL 1.742 8.71

Trace metal solution

Substock Substance Stock solution (g/L) Concentration in primary concentration (g/L) Final concentration in medium (mg/L) (adding 5 mL/L)
1. Na2EDTA•2H2O 4.360 0.218 4.360
2. FeCl3•6H2O 3.150 0.1575 3.150
3. ZnSO4•7H2O 0.222 0.0011 0.022
4. CoCl2•6H2O 0.010 0.0005 0.010
5. MnCl2•4H2O 0.180 0.009 0.180
6. Na2MoO4•2H2O 0.006 0.0003 0.006
7. CuSO4•5H2O 0.001 0.00005 0.001
8. H3BO3 1.000 0.05 1.000

f/2 vitamin solution

Substock Substance Stock solution (g/L) Concentration in primary concentrate (g/L) Final concentration in medium (mg/L)
1. Vitamin B12 (Cyanocobalamin) 0.001 0.00005 0.001
2. Biotin 0.001 0.00005 0.001
3. Thiamine 0.200 0.0100 0.200

To prepare concentrate:

Combine stocks solutions, in the order listed above, to make 200 mL total volume of primary concentrate and 50 mL total volume of secondary concentrate. These volumes will prepare 10L of full-strength WC medium. Concentrate may be stored in the fridge in the dark until needed

To prepare medium:

The final concentrations shown above are to prepare a 100% WC(ed) medium by adding 20 mL of primary concentrate plus 5 mL of secondary concentrate to 975 mL of purified water (e.g., distilled, Nanopure, Milli-Q). Stir, pH adjust to 8.0 - 8.5 if necessary with 1N HCl or 1N NaOH. If sterile medium is needed, then the final medium may be filter-sterilized through a 0.22 um filter and dispensed aseptically into sterile vessels or autoclaved directly in the vessels. All concentrate/stock solutions and prepared medium should be stored in the fridge in the dark until needed.