BY J. DE FLINES AND W. F. VAN DER WAARD (Research Laboratories of the Royal Netherlands Fermentation Industries Ltd., Delft) AND W. J. MTJS, L. A. VAN DIJCK AND SA SZPILFOGEL (Research Laboratories, NV Organon, Oss) The microbiological rccction of 19-nortestosterone with Colletotrichum derridis yielding mainly 12,G-hydroxy-l9-nortestosterone, is described. ... Microbiological hydroxylation in the 12,9-position in the steroid-series has as yet been ...