Ascomycin, a well-known immunosuppressant and antifungal, is used for the treatment of autoimmune diseases and skin diseases, and to prevent organ rejection after transplant. Apart from active pharmaceutical ingredient, Ascomycin is useful as a key starting material for the synthesis of Pimecrolimus (Kumar et al., 2007). Ascomycin is produced industrially by microbial fermentation through Streptomyces hygroscopicus subsp. ascomyceticus. 

[1] Kumar, P., Sharma, S.K., Malviya, H.K., Balasubramaniam, R.C., Dalal, A., 2007. An Improved Fermentation Process for Preparing Ascomycin. WO 2007/029082.

[2] Tadashi et al. (1966) reported an antifungal agent identified as ascomycin which is prepared by the process which comprises cultivating a strain of Streptomyces hygroscopicus var.ascomyceticus under submerged aerobic condition.