BG11 Broth M1541
BG11 Broth is a universal medium for the cultivation and maintenance of blue green algae (cyanobacteria).
Ingredients Gms / Litre Sodium nitrate 1.500 Dipotassium hydrogen phosphate 0.0314 Magnesium sulphate 0.036 Calcium chloride dihydrate 0.0367 Sodium carbonate 0.020 Disodium magnesium EDTA 0.001 Citric acid 0.0056 Ferric ammonium citrate 0.006 Final pH after sterilization ( at 25°C) 7.1 **Formula adjusted, standardized to suit performance parameters
Suspend 1.627 grams in 1000 ml distilled water. Heat if necessary to dissolve the medium. It is recommended to adjust pH with 1 M NaOH or HCl if it does not achieve 7.1. Dispense in flasks or as desired. Sterilize by autoclaving at 121°C for 15 minutes. Cool the medium to room temperature. For marine species make as solution of 10 g/L sodium chloride and 1 g/L Vitamin B12. Add 20 ml of this solution (sterile filtered) to 1000 ml D/W.
Principle And Interpretation
This medium supports growth of photoautotrophic blue green algae (1,2). They require light as source of energy. Synthetic nitrogen and carbon sources and other inorganic salts comprise this medium. Exposure to light intensity of 2,000 to 3,000 lux is optimal for cultivation of blue green algae. Neon light source is found to be sufficient to provide this illumination. For maintenance of blue green algae exposure for period of 24 hours a day is optimal .Often the flasks kept for incubation may be covered with grease proof paper. They grow optimally at room temperature between range of 20-25°C. Similar medium with added trace metals is cited in ATCC as Medium 616 for maintenance of Synechocystis species (3).
Storage and Shelf Life
Store below 30°C in tightly closed container and the prepared medium at 2-8°C. Use before expiry date on the label.
1.Allen, M.M, Steiner,R.Y .J.Gen.Microbiol. 51 ,203 (1968). 2.R.Y. Stanier,R. Kunisawa,M. Mandel, & Cohen-Bazire,G. Bacteriol.Rev. 35: 171-205 (1971). 3.ATCC Catalogue of Bacteria & Bacteriophages 18th edition, 1992.