Establishment of a pure culture of the hitherto uncultured unicellular cyanobacterium Aphanothece sacrum, and phylogenetic position of the organism.

Aphanothece sacrum, an edible freshwater unicellular cyanobacterium, was isolated by using novel synthetic media (designated AST and AST-5xNP). The media were designed on the basis of the ratio of inorganic elements contained in A. sacrum cells cultured in a natural pond.