Phencomycin, a new antibiotic from a Streptomyces species HIL Y-9031725.

Strain HIL Y-9031725 was isolated from a soil sample collected in India. The strain was identified as belonging to the genus Streptomyces using the methods described by Shirling and Gottlieb.2) A loopful of mature slant culture of Streptomyces Y-9031725 was inoculated into Erlenmeyer flasks (500 ml capacity) containing 100 ml of seed medium consisting of glucose 1.5%, soyabean meal 1.5%, corn steep liquor 0.5%, CaCO3 0.2% and NaCl 0.5%, pH 6.5 before autoclaving. The flasks were cultivated at 27°C on a rotary shaker at 240rpm for 72 hours. The resultant seed culture (9%) was inoculated into 15 liter fermenter containing 10 liters of production medium consisting of glucose 1.5%, soybean meal 1.5%, corn steep liquor 0.5%, CaCO3 0.2% and NaCl 0.5%, pH 6.5 before autoclaving. Desmophen (4 ml) was added as an antifoaming agent to the contents of the fermenter. The fermentation was carried out at 27°C under stirred conditions at 150rpmwith aeration at a rate of 10 liters/minute for 45 hours. The production of the antibiotic was monitored by its antibacterial activity against Staphylococcus aureus 209P. The culture filtrate (8 liters), obtained after separating mycelium by centrifugation, was passed through a column of HP-20 (400 ml). The column was washed with demineralized water (5 liters) and eluted with 50: 50 watermethanol (5 liters) and 20 : 80 watermethanol (8 liters) respectively. The active eluates wereconcentrated under reduced pressure to 200ml. It was then acidified to pH 5 and extracted with ethyl acetate (3 x 150ml). The combinedethyl acetate extracts were concentrated to dryness under reduced pressure. The crude material (850mg), thus obtained, was subjected to a silica gel (200 ~ 300 mesh, 150 g) column and eluted with dichloromethane ethyl acetate mixture. The active eluates, which eluted out in 0.5 ~ 1 % ethyl acetate in dichloromethane, were concentrated to dryness followed by crystallization in dichloromethane to obtain pure phencomycin (1) (150mg).