Antibiotic Produced by Thermoactinomyces viridis n.sp.1

To our knowledge the only report of an antibiotic produced by a thermophilic actinomycete was published by Schone (1951). The antibiotic was produced by Streptomyces thermophilus, and was named thermomycin. Schone obtained an antibiotic titer of 256 units per ml in 4 days at 60 C in stationary bottles using a buffered medium which contained 10 per cent blood serum. Extraction of this culture filtrate with ether, followed by evaporation yielded a yellow powder which inhibited Corynebacterium diphtheriae at a concentration of 12 ,ug per ml. Thermomycin was found to be most active against C. diphtheriae and against Listeria monocytogenes to a much lesser extent. All other organisms tested were insensitive to thermomycin. Injection of 2 ml of culture filtrate (256 u per ml) into each of 20 mice did not cause a toxic reaction. The present paper deals with the production, recovery, purification, and microbial spectrum of thermoviridin. The organism which produces this antibiotic is considered to be a new species in the genus Thermoactinomyces. The name Thermoactinomyces viridis is suggested for the organism.