Pigmented variants of Tolypocladium inflatum in relation to cyclosporin A production.

We have isolated four distinct colony types of the fungus Tolypocladium inflatum, the producer of the immunosuppressive agent cyclosporin A: morphologically normal white, red, and orange colonies and morphologically diverse tiny brown colonies. In liquid cultures, white normal and brown colonies developed into yellow broths. The broth of the brown colony had a low final pH and low cyclosporin production, whereas orange and red colonies had dark brown and even black broths with higher final pH and high cyclosporin production. The specific production of cyclosporin A by the red colony was three times that of the white normal colonies.