Effective multi-step functional biotransformations of steroids by a newly isolated Fusarium oxysporum SC1301

A fungus Fusarium oxysporum SC1301 was isolated from soil samples, which could transform androst-4-ene-3,17-dione, androst-1,4-diene-3,17-dione, dehydroepiandrosterone, progesterone, testosterone, and pregnenolone to give testolactone in 76–98% yields. Especially, for progesterone and pregnenolone, multi-step functional transformations, including oxygenative esterification of 20-ketosteroids, hydrolysis of ester, oxidation of C-17 OH group, oxygenative lactonization of 17-ketosteroids, 1-dehydrogenation, oxidation of C-3 OH group and Δ5→4 Cdouble bond; length as m-dashC bond migration, could proceed effectively to yield testolactone as a single product. This is the first example that a F. oxysporum species shows catalytic capability of ring-D lactonization. The results are remarkably distinguished from those previously reported for the closely-related fungus F. oxysporum var. cubense, which predominantly mediates the hydroxylations at different positions of steroids. In addition, F. oxysporum SC1301 may serve as a valuable biocatalyst for the production of testolactone.