Overview:
BG11 Broth is the universally accepted, chemically defined liquid medium for the axenic cultivation of freshwater cyanobacteria (especially Synechococcus, Anabaena, Nostoc, Microcystis, Spirulina) and many unicellular green algae. Originally formulated by Stanier et al. (1971) at the Pasteur Institute, it remains the gold-standard reference medium in phycology, biotechnology, and ecological research (ISO 10712, OECD 201, Allen & Stanier 1968).
Applications:
Axenic culture of most freshwater cyanobacteria
Growth of Synechococcus elongatus PCC 7942, Anabaena PCC 7120, Nostoc, etc.
Production of cyanobacterial biomass, pigments, and bioactive compounds
Toxicity testing with cyanobacteria (OECD 201)
Reference medium for cyanobacterial genomics and physiology
Key Features:
Nitrate as sole nitrogen source (favours non-N?-fixing strains)
Low phosphate, trace metals optimized for cyanobacteria
No combined organic carbon � strictly autotrophic
Transparent ? ideal for photosynthetic studies
Composition (per liter):
NaNO? 1.5 g
K?HPO?�3H?O 0.04 g
MgSO?�7H?O 0.075 g
CaCl?�2H?O 0.036 g
Citric acid 0.006 g
Ammonium ferric citrate (green) 0.006 g
EDTA�Na? 0.001 g
Na?CO? 0.02 g
Trace metal mix A5 1.0 mL
Trace metal mix A5 (per liter of mix):
H?BO? 2.86 g
MnCl?�4H?O 1.81 g
ZnSO?�7H?O 0.222 g
Na?MoO?�2H?O 0.39 g
CuSO?�5H?O 0.079 g
Co(NO?)?�6H?O 0.0494 g
Final pH: 7.4�7.6 after autoclaving (adjust with 1 N NaOH if necessary)
Preparation:
Dissolve macronutrients and Na?CO? in ~900 mL distilled water.
Add 1 mL trace metal mix A5.
Adjust volume to 1 L and pH to 7.5.
Dispense into flasks or tubes.
Autoclave at 121�C for 15 minutes (or filter-sterilize for heat-sensitive strains).
Variants:
BG11? (zero nitrogen) � omit NaNO? for N?-fixing strains
BG11 + 2�5 mM NaHCO? � for high-density cultures
Incubation:
25�30�C, continuous illumination 20�100 �mol photons m?� s?�, gentle shaking or bubbling with air/CO?.
Storage:
Prepared medium: 2�8�C, protected from light, use within 3 months.
For laboratory and research use only. Reference medium: Stanier et al. (1971), Rippka et al. (1979), ISO 10712.