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 a process for making a highly productive fusant of Tolypocladium inflatum, a producing strain of cyclosporin A with immunosuppressive properties wherein the selection of the fusant KD461, designed to produce a large amount of cyclosporin A, was made available by the following steps of: developing amino acid-dependent mutants of Tolypocladium inflatum, wild strain isolated from soil, which mutants are induced by UV radiation; conjugating L-valine-dependent and L-leucine-dependent mutants to promote the demand and utility of L-valine and L-leucine, precursors of cyclosporin A, together with an organic nitrogen-source.