Resumo. AbstractIn a preliminary study of antimicrobial activity, the isolate Streptomyces sp. 1S was selected to its highpotential as bioactive metabolites producer. This isolate showed a broad spectrum of activity, inhibiting46 out of 54 test microorganisms used in the assay (gram-positive and gram-negative bacteria, yeastsand filamentous fungi). In this study it was evaluated the influence of environmental conditions such asculture medium, temperature of incubation, agitated or static culture and time of growth for productionof bioactive molecules. Therefore, we used seven media: starch casein broth (SC), medium proposedby Sahin (S), Bennett’s medium (B), nutrient broth (NB), medium malt and yeast extract (ISP2) andtrypticase soy broth (TSB) and modified Czapeck Dox broth (CPD). The temperatures evaluated 28, 30,35 and 40 °C, on stirring and static culture. For each test the antimicrobial activity was determined,pH and cell biomass. From all assays performed, the best condition for antimicrobial production wasobserved from extracts that resulted from the growth of Streptomyces sp. 1S in ISP2 medium, at atemperature of 28 °C, for 96 hours of culture under agitation. The extract obtained inhibited 15 of the 17test microorganisms used in this study, including multirresistant microorganisms such as Staphylococcusaureus MRSA, Enterococcus sp. and Salmonella enterica subsp. enterica Enteritidis.