Degradation of progesterone by aspergilli‐side chain cleaving enzymes

Abstract

The transformation properties of different aspergilli were tested. Our strains possess the capacity of degrading of progesterone side chain. A*-androstene-3,17-dione, testosterone, and testololactone were detected in all cases but produced in different yields. Two strains.namely, Aspergillus niger 214 and A . flavus 181 proved to be the most active transformers.The transformation abilities of these two strains are profoundly affected by composition of the fermentation medium employed. The media containing ill-defined compounds, e. g . peptone or yeast extract favour the production of enzymes ca.talyzing the degradation of the progesterone side chain. Various enzymic transformations of progesterone with these two strains were studied by allowing the fermentation to proceed a t different time intervals. It was possible to illustrate schemes for such transformation reactions.A systematic investigation of the ability of different aspergilli to perform oxidative transformation of progesterone a t C-11 was carried out (EL-REFAI and SALLAM 1972, ABDEL-FATTAH et al. 1972). We observed that hydroxylation of progesterone occurs at C-6, 11, 17, and 21 by some active strains. However, other experimental strains of the genus Aspergillus failed to perform these enzymatic reactions. It was found of interest therefore to study and evaluate the transformation properties of this latter group of aspergilli on the progesterone molecule. Results and discussion concerning these studies are given in the present paper. Material and methodsMicroorganisms: The different organisms used in this work were collected by the Centre of Cultures of this laboratory. They were isolated from local habitats and identified through the American Type Collection, Washington, and the Central Bureau Voor Schimmel Cultures, Baarn (Holland). Table 2. The cultivation was made in 250 m l Erlenmeyer flasks, each containing 60 ml medium. The flasks were sterilized a t 1 atmosphere for 20 min and inoculated with 2 ml of inoculum suspension of a 48 hr. old culture of the pure organism. The culture flasks were agitated on a reciprocal shaker (110 strockes/min, amplitude 7 om) a t 30 2 "C for 48 hr. Thereafter, 10 mg of progesterone dissolved in lml of 96% ethanol were added to each flask and fermentation was continued for another 48 hr.