S TUDY is aimed to ferment, isolate and characterize a significant antimicrobial metabolite from the marine thermophilic, Saccharomonospora viridis AHK 190. Maximum yield of a wide spectrum antimicrobial agent was optimized and fermented by Saccharomonospora viridis AHK 190. Extraction, purification and molecular formula elucidation of the fermented agent were also assayed. A diversity of human microbial pathogens was applied as indicators in the antibiosis assay. Thin layer chromatography technique was employed for partial purification of the antimicrobial agent. Spectral and elemental analysis studies were as well screened for molecular formula elucidation of the purified compound. Actinomycete optimum growth and maximum antibiotic fermentation were confirmed after 3 days of incubation at 55oC under the effect of pH at 8.0 and shaking at 180 rpm. In addition, maximum antibiotic production was achieved with galactose, aspartic acid, 3.0% NaCl and 0.11% K2HPO4; while pyridoxine, starch, 5.0% NaCl and 0.11% K2HPO4 encouraged the actinomycete optimum growth. Elucidated molecular formula of the under-test antimicrobial compound was found as C31H34O4S3 of molecular weight = 567. It is of a new chemical formula different from other current main classes of antibiotics.