Abstract: A nystatin-resistant mutant microorganism belonging to Aspegillus genus is provided for preparing triol heptanoic acid, a precursor of 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor. A mutant Aspergillus terreus CLS247-13, KCTC 0673 BP is prepared by treating Aspergillus terreus CLS216-7, KCTC 0359 BP with ultraviolet ray or chemical mutagens. The mutant provides high productivity (at least 11.5 g/L, 95/6% of the total product) of triol heptanoic acid, while reducing (less than 0.53 g/L, 4.4% of total product) productivity of triol heptanoic acid analogues. Since the nystatin-resistant mutant strain CLS347-13 has a capability of producing triol heptanioc acid with a high yield in a short period of culture time compared with known triol heptanoic acid producing strains, it can be widely used in industrial applications.

Abstract: The present invention relates to Streptomyces sp. producing tautomycetin which possesses an immunosuppressive or antibacterial activities, a process for preparing tautomycetin from the said microorganism, and an immunosuppressant or immunosuppressive pharmaceutical composition comprising tautomycetin as an active ingredient which suppresses interleukin-2 production, CD69 and interleukin-2 receptor(IL-2R) expression on the cell surface, and graft rejection in the organ transplantation. The present inventors isolated a soil microorganism which produces a substance possessing antibiotic and immunosuppressive activities, and identified the said microorganism and substance as a novel Streptomyces sp. and tautomycetin, respectively.