BG-11 without NO₃ concentrate | Canadian Phycological Culture Centre

*This formulation has been modified from the original.

Reference: Rippka, R., Deruelles, J., Waterbury, J., Herdman, M., & Stanier, R. (1979). Generic assignments, strain histories and properties of pure cultures of cyanobacteria. Journal of General Microbiology. 111, 1-61. doi:10.1099/00221287-111-1-1

This concentrate can be used for freshwater cyanobacteria that fix nitrogen (heterocystous species).

Stock	Substance	Primary stock (g/L)	Volume used to prepare 100 mL concentrate	Concentrated stock (g/L)	Final concentration in medium (mg/L) (adding 50 mL/L)
	Purified H₂O	–	40 mL	–	–
1.	NaNO₃	150	–^a	–^a	1500
2.	K₂HPO₄	30	10 mL	0.6	30
3.	MgSO₄•7H₂O	75	10 mL	1.5	75
4.	CaCl₂•2H₂O	36	–^b	–^b	36
5.	Citric Acid	6	10 mL	0.12	6
5.	Ferric Citrate or Ferric Ammonium Citrate ^c	6	10 mL	0.12	6
6.	Na₂EDTA•2H₂O	1	10 mL	0.02	1
7.	Na₂CO₃	20	–^b	–^b	20
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: The NaNO₃ (Stock 1) stock solution that is normally added to BG-11 medium is excluded from the concentrate. If NO₃ is desired, then add this stock separately (at a rate of 10 mL/L) during preparation of the medium.

^bNOTE: The CaCl₂•2H₂O (Stock 4) and NaCO₃ (Stock 7) stock solutions that are normally added to BG-11 medium are excluded from the concentrate as they precipitate out. Add these stocks separately (at a rate of 1 mL/L each) during preparation of the medium.

^cNOTE: Original recipe called for the use of Ferric Ammonium Citrate at same rate as Ferric Citrate. Ferric Citrate (used by CPCC) appears to be an acceptable substitute.

Trace metal solution

Substock	Substance	Primary stock (g/L)	Concentration (g/L)	Final concentration in medium (mg/L)
1.	H₃BO₃	2.86	0.286	2.86
2.	MnCl₂•4H₂O	1.81	0.181	1.81
3.	ZnSO₄•7H₂O	0.222	0.022	0.222
4.	Na₂MoO₄•2H₂O	0.390	0.039	0.390
5.	CuSO₄•5H₂O	0.079	0.0079	0.079
6.	Co(NO₃)₂•6H₂O	0.049	0.0049	0.049

f/2 vitamin solution

Substock	Substance	Primary stock (g/L)	Concentration (g/L)	Final concentration in medium (mg/L)
1.	Vitamin B12 (Cyanocobalamin)	0.001	0.0001	0.001
2.	Biotin	0.001	0.0001	0.001
3.	Thiamine	0.200	0.0200	0.200

To prepare concentrate:

To make 100 mL of concentrate, combine stocks solutions, in the order listed above, to make 100 mL total volume (will prepare 2L of BG-11 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% BG-11 w/o NO₃ medium by adding 10 mL of the concentrate plus 1 mL of Stock 4 and 1 mL of Stock 7 to 988 mL of purified water (e.g., distilled, Nanopure, Milli-Q). If NO₃ is desired, then Stock 1 is added at a rate of 10 mL/L by adding 10 mL of the concentrate plus 10 mL of Stock 1 plus 1 mL of Stock 4 and 1 mL of Stock 7 to 978 mL of purified water. Stir, pH adjust to 7.5 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. Prepared medium may be stored in the fridge in the dark until needed.