The effects of the composition and rheology of the fermentation medium on the antibiotic production by Streptomyces hygroscopicus CH-7 were studied. To increase the yields of hexaene H-85 and elaiophylin, the basic fermentation medium was reformulated using different carbon (glucose, lactose, ribose, fructose and trehalose) and nitrogen (isatin-Schiff bases) sources. The maximum yields of hexae...