Bold's Basal Medium (modified)

This medium is highly enriched and is used for many of the green algae.
Reference: Stein, J. (ED.) Handbook of Phycological methods. Culture methods and growth measurements. Cambridge University Press. 448 pp.

Stock Substance Concentration Amount added to medium (mL/L)
1. KH2PO4 8.75 g/500 mL 10 mL
2. CaCl22H2O 12.5 g/500 mL 1 mL
3. MgSO47H2O 37.5 g/500 mL 1 mL
4. NaNO3 125 g/500 mL 1 mL
5. K2HPO4 37.5 g/500 mL 1 mL
6. NaCl 12.5 g/500 mL 1 mL
7. Na2EDTA2H2O 10 g/L 1 mL
KOH 6.2 g/L
8. FeSO47H2O 4.98 g/L 1 mL
H2SO4 (concentrated) 1 mL/L
9. Trace metal solution See below 1 mL
10. H3BO3 5.75 g/500 mL 0.7 mL
11. f/2 vitamin solution (optional) See below 1 mL

Stir and adjust the pH to 6.8. Filter-sterilize into sterile glassware using a 0.22 um filter or autoclave the medium.

Options: The addition of f/2 vitamins or 5 ml of soil extract is also beneficial to some algae. The CPCC currently adds f/2 vitamins to the BBM medium for all strains. To prepare a less rich medium, prepare a 10% BBM solution.

Trace metal solution

Substance Concentration (g/L)
1.  H3BO3 2.86 g
2.  MnCl24H2O 1.81 g
3.  ZnSO47H2O 0.222 g
4.  Na2MoO42H2O 0.390 g
5.  CuSO45H2O 0.079 g
6.  Co(NO3)26H2O 0.0494 g

Dissolve each of the above substances separately prior to adding the next on the list.

f/2 vitamin solution

Substock solutions:

First prepare separate substock solutions of cyanocobalamin (Vitamin B12) and biotin in purified water (e.g., Milli-Q, Nanopure, distilled water).

Substock Substance Concentration
1. Vitamin B12 (Cyanocobalamin) 10 mg/10 mL
2. Biotin 5 mg/50 mL

Working stock solution:

Then prepare the final working solution by combining the following amounts of the two substock solutions plus thiamine HCl to 100 mL of purified water.

Substance Concentration (per 100 mL)
1.  Vitamin B12 (Cyanocobalamin) 0.1 mL
2.  Biotin 1.0 mL
3.  Thiamine HCl 20 mg

Dispense the working solution as 1 mL aliquots in cryovials for convenient use when preparing the medium. Store the remainder of the primary stocks and working solution in polyethylene bottles. Wrap vials/bottles with Parafilm to avoid moisture loss and store all solutions frozen.

References: Guillard and Ryther 1962, Guillard 1975