Abstract
The strain SL-387 which produces new inhibitors of aminopeptidase M, MR-387A and B, was isolated from a soil sample. The strain has branched substrate mycelia, from which aerial hyphae develop in the form of open spirals. Spore surface is smooth. Melanoid and soluble pigme- nts were observed. The isolate contains LL-diaminopimelic acid in its cell wall hydrolysate, and has no pectinolytic activity. The strain SL-387 is closely related to Streptomyces griseoruber and S. naganishii, but is different from these strains in some cultural and physiological characteristics. This strain was, therefore, designated as Streptomyces sp. SL-387. The effects of several carbon and nitrogen sources on the production of the inhibitor were examined. Among them, glucose, galactose, mannose, and xylose were effective as a carbon source and soybean meal, soytone, fish meal, and gluten meal were effective as a nitrogen source. The maximum peak of the inhibitor production in jar fermentor was obtained on the fifth day of culture.