Volutin granules

Volutin granules are an intracytoplasmic storage form of complexed inorganic polyphosphate, the production of which is used as one of the identifying criteria when attempting to isolate Corynebacterium diphtheriae on Löffler's medium. Polyphosphate granules display the metachromatic effect, appearing red when stained with methylene blue. Volutin granules can also be found in the cytoplasm of Saccharomyces, a genus of ascomycete fungi. They are characteristic for different species and depend on the age and condition of the culture.

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