Microbial conversion of milbemycins: microbial conversion of milbemycins A4 and A3 by Streptomyces libani.

28-hydroxymilbemycins, 1 3/?,30-dihydroxymilbemycins, and others.4~8) On the other hand, Ramos Tomboet al. have reported 13/Miydroxylation and 14, 1 5-epoxidation of milbemycins by Streptomyces violascens ATCC31560.9) During our screening of microbial conversion of milbemycin A4 (la), we observed that an actinomycete, strain SANK65087, newly isolated from soil, converted milbemycin A4 (la) to a variety of conversion products. The present paper deals with purification and identification of converted products from milbemycins A4 (la) and A3 (2a) using this microorganism. Strain SANK 65087 was isolated from a soil sample at Adelaide in Australia. On the descriptive media of Shirling and Gottlieb,10) and Waksman,11} after 14days at 28°C, the aerial