BG11 Broth is a chemically defined liquid culture medium universally accepted for the axenic cultivation of freshwater cyanobacteria and selected unicellular green algae. Originally formulated by Stanier and colleagues and subsequently standardised by Rippka et al., BG11 remains the gold-standard reference medium in phycology, biotechnology, and aquatic ecology.

The medium is optimised for photoautotrophic growth, using nitrate as the sole nitrogen source, no combined organic carbon, and carefully balanced trace metals. It is widely used for cultivation of genera such as Synechococcus, Anabaena, Nostoc, Microcystis, and Spirulina, as well as for cyanobacterial genomics, physiology, and toxicity testing.

BG11 Broth provides all essential inorganic nutrients required for cyanobacterial growth while excluding organic carbon sources. Growth is driven by photosynthesis, with nitrate supplying nitrogen and a low-phosphate background minimising precipitation and metabolic interference. A defined trace-metal system (A5) supports enzymatic and photosynthetic processes while maintaining clarity for optical measurements.

Total dehydrated powder: 1.6894 g/L | Final pH 7.1 at 25°C. This total is summed directly from the itemised formula above and is fully independently verifiable — it differs slightly from a commercial reference product's published suspend weight (1.642 g/L), which reflects an undisclosed proprietary adjustment we could not reconcile.

Each released batch of BG11 Broth (AS-1137) is supplied with a lot-specific Certificate of Analysis documenting the finished-product quality checks below.