[Dynamics of the biosynthesis of nystatin components by Act. noursei, strain 153 under controlled culture conditions].

The ratio of the nystatin components produced under various cultivation conditions was studied. It was found to change during the greater part of the fermentation period and depend on the carbohydrate content in the medium. Under the conditions of the uncontrolled batch process the ratio of components A1 and A2 during the first 36 hours of the cultivation changed from 7.2 to 6.2. When the rate of the antibiotic synthesis was maximum (42 - 72 hours), the ratio of A1 and A2 components was practically constant and equal to 5.5 - 5.2. Beginning from the 72nd hour, when the rate of nystatin synthesis decreased, the ratio of A1 and A2 components increased up to 6.6 - 9.0. Periodical addition of high amounts of glucose during the idiophase promoted activation of the synthesis of the less active A1 component. On momentous addition of glucose in the amounts of 1, 2 and 3 per cent the ratio of A1 and A2 components increased by the end of the process up to 14.3, 16.6 and 22.4 respectively. The data suggest that the nystatin components and especially the active A2 component which is more stable on storage are sensitive to accumulation of glucose catabolites.