Antibiotic Complex SP-351 Produced by a Psychrophile, Streptomyces sp. No. 351

Abstract

In the course of a screening study for antibiotics using psychrophilic microorganisms a water-insoluble antibiotic complex, SP-351, was found in the culture filtrate of a psychrophilic actinomycete, strain No. 351. This active principle was isolated and characterized as a cyclicpolylactone antibiotic. The SP-351-producing strain was classified as a facultative psychrophile and identified as Streptomyces phaeochromogenes.
The main components of the antibiotic complex SP-351 changed with the composition of the culture medium but not with culture temperatures. Component A was exclusively produced in a medium composed of roasted soybean powder and glycerol; components B and C in a medium composed of soybean, glycerol and potassium nitrate; and components A and D in a synthetic medium containing a hydrocarbon, alcohol or ester as the sole carbon source. Maximum production of SP-351 from n-paraffin and methyl acetate was 10 and 15mcg/ml, respectively.
SP-351 showed strong antibacterial activity against Gram-positive bacteria and acidfast bacteria at 0.1_??_0.3mcg/ml concentrations.