A new antibiotic, bulgerin, active against phytopathogenic fungi.

In the course of our screening program, a streptomyces strain S-288 was found to produce an antibiotic which exhibits a bulging effect^ against Piricularia oryzae. This strain was isolated from a soil sample collected at Mie Prefecture, Japan. As a result of taxonomic studies by the usual methods, its characteristics are summarized as follows: no whorl, no spiral, smooth surface of spores, yellowish brown growth with brownish gray aerial mycelium and yellowish brown soluble pigment on various media, non-chromogenic type, proteolytic action with peptonization of milk, and liquefaction of gelatin. Among the known species of streptomyces having these characteristics, Streptomyces aburaviensis Nishimura et al.2) and Streptomyces aburaviensis var. ablastmyceticus Hamada et Okami3) are most closely related to this strain. However, some differences are found among these strains as shown in Table 1. Therefore, the strain S-288 is designated as Streptomyces aburaviensis var. tuftformis var. nov. Mayama et Kawamura. The antibiotic, named bulgerin, was isolated from the fermentation broth of the