Nocardia species aromatized 19-hydroxyprogesterone, 3beta, 19-dihydroxy-pregn-5-en-20-one 3-acetate and pregn-5-ene-3beta, 19, 20beta-triol 3-acetate, without cleavage of the side chain, into 3-hydroxy-19-norpregna-1,3,5 (10)-trien-20-one. Septomyxa affinis aromatized the ring A and cleaved the side chain of 19-hydroxyprogesterone to yield estrone. With 19-hydroxypregna-4, 7-diene-3, 20-dione a...