ATIVIDADE ANTIMICROBIANA DE METABOLITOS SECUNDÁRIOS DE Streptomyces spp, ISOLADOS DE CULTURA DE SOJA DO SUL DO ESTADO DO MARANHÃO

Abstract

Brazil has an extensive territorial area with the presence of several biomes. Soil as abiotic components of biomes can be described as a grouping of chemical and biological reactions and processes responsible for the formation of land layers and plant development, where filamentous bacteria called Actinomycetes can be found. These microorganisms have a big capacity to produce bioactive compounds, which allows antagonism to other microorganisms in the competition relationship for space, causing injury and/or destruction of other organisms. Based in these aspects, the present work object to verify the antimicrobial action of secondary metabolites produced by Actinomycetes isolated from soil used for soybean planting in Maranhao state. For this, soil samples were collected and performed morphological and molecular identification tests, enzymatic and antimicrobial activity assays such as solid medium assay (agar block), liquid medium assay (diffusion agar), evaluation of the Minimum Inhibitory Concentration (MIC) and synergism against the microorganisms Klebsiella pneumoniae ATCC 0023, Pseudomonas aeruginosa ATCC 0026, Staphylococcus aureus ATCC 6538, Corynebacterium diphtheriae ATCC 27012, Cryptococcus gattii ATCC 24065 and preliminary chemical identification of the extracts. Ten strains were isolated, the mosto f them being Streptomyces. Of the isolates, only the strains Act 01, Act 03, Act 06 showed antimicrobial activities and these three isolates were identified as belonging to the genus Streptomyces. All three strains were able to produce cellulase, amylase and protease enzymes. In addition to presenting a halo of inhibition for all tested pathogens with the exception of Klebsiella pneumoniae. Regarding the CMI, it presented inhibition results for Pseudomonas aeruginosa ATCC 0026 (500 μg/mL), Staphylococcus aureus ATCC 6538 (1000 μg/mL), Cryptococcus gattii ATCC 24065 (125 μg/mL). Regarding the compounds isolated from the extract, the presence of flavonoids, terpenes and alkaloids was determined. Them, the Streptomyces isolates demonstrated antimicrobial action and more tests need to be carried out to ensure the biological safety of these bioactives.