Fungos de solo do semiárido pernambucano como fonte de compostos com atividade antibacteriana

Abstract

Microorganisms are the main agents of biochemical activities occurring in the soil, being important for the proper functioning of ecosystems, in addition, several natural compounds are produced by microorganisms belonging to the soil, especially fungi, which are an excellent source for exploration of new secondary metabolites with antimicrobial activity, for the production of antibiotics. Thus, the objective of this work was to isolate, quantify and evaluate the antimicrobial potential of filamentous fungi isolated from soil in a preserved area of the Pernambucano semi - arid region, collected at the State Conservation Park Mata da Pimenteira, in the municipality of Serra Talhada - PE. For this, the soil samples were collected in two periods (drought and rain), from which the isolation and quantification of fungi in two culture media (Dextrose Bata Agar and Sabouraud Agar - SAB) by the serial dilution technique. This step was performed with three replicates in each period. Subsequently, the test of antimicrobial activity of fungi against bacteria was also carried out using the gelose block methodology. As a result, a higher quantification of fungi was obtained in the dry season, with higher growth of CFUs in BDA culture medium with 8.6 x 106 CFU / g, followed by 8.3 x 104 CFU / g in SAB. Thirty-one colonies were selected from the collection in drought, of which nine were identified to date as Aspergillus, Penicillium or Eurotium and of which, 20 were submitted to the antimicrobial activity test. Isolate 05 showed a 32 mm diameter inhibition halo against Staphylococcus aureus. Five other fungal isolates were active against Escherichia coli and five against Klebsiella; no fungus has shown activity against Salmonella. In relation to the rainy period, 11 isolates were identified, such as Aspergillus, Penicillium, Cladosporium and Paecilomyces. Of the isolates submitted to the antimicrobial activity test, none of the isolates showed inhibitory activity against the bacteria. From the obtained results, it was possible to verify the antimicrobial potential presented by the fungi in the period of drought, emphasizing its importance in search of new compounds of interest of the pharmaceutical industry.