Bioxalomycins, new antibiotics produced by the marine Streptomyces sp. LL-31F508: taxonomy and fermentation

An actinomycete strain designated LL-31F508 was isolated from an intertidal sediment sample collected in Key West, Florida. Culture LL-31F508 was assigned to the Streptomyces genus based on the presence of LL-diaminopimelic acid (DAP) in the cell wall and observations of spiny spores using scanning electron microscopy (SEM). Excellent antimicrobial activity against Staphylococcus and Enterococcus spp. were detected in both the supernatant and cell extract samples from fermentations of culture LL-31F508. Production of antibiotic activity peaked at 48-50 hours and closely paralleled cell growth, during which time glucose was more rapidly assimilated than dextrin. A series of new antibiotics called the bioxalomycins was identified as the antibacterial products from fermentations of this culture. Fermentation conditions for production of bioxalomycin alpha differed substantially from those required for production of a related compound, naphthyridinomycin, by the reference culture Streptomyces lusitanus NRRL 8034.