This master thesis addresses the change in metabolic profiles during co-cultivation of two bacterial species, Bacillus subtilis and Streptomyces rimosus. Bacteria were cocultivated on the solid medium and metabolites were extracted after incubation using methanol. Methanol extracts were then analysed by thin-layer chromatography. We observed that during co-cultivation with B. subtilis PS-216 on solid SM and ISP5 media the S. rimosus R7 synthesizes a compound that we perceived as a violet spot in the TLC profile at a wavelength of 365 nm. The violet spot appeared also when we co-cultivated B. subtilis PS-216 with S. rimosus M4018 but not with the strain S. rimosus W on solid SM medium. We have also tested various mutants (?degQ, ?srfA, ?katA, ?spo0A) of B. subtilis PS-216 and found that they still induce production of the violet spot during co-cultivation with S. rimosus R7. Moreover, B. subtilis PS-216 metabolic profile changed in co-cultivation with S. rimosus R7 as compared to monoculture. Next, we investigated the trigger produced by B. subtilis PS-216 that induces the synthesis of the violet spot in TLC profile of S. rimosus R7. We found that the unknown trigger is soluble in medium, fairly temperature resistant (24h on 80 °C) and is not a peptide. Synthesis of the trigger produced by B. subtilis PS-216 is independent of the presence of S. rimosus R7 as the violet spot appears after the addition of the spent medium of B. subtilis PS-216.