1978 Volume 31 Issue 11 Pages 1124-1131
A mutant strain derived from Nocardia mediterranei N813 was found to accumulate a number of novel ansamycins structurally related to the protostreptovaricins and to rifamycin W. One of the main components of this ansamycin complex, protorifamycin I (8-deoxyrifamycin W), was purified and identified by means of chemical and spectroscopic methods.