Avaliação de meios e condições de cultivo de fungos filamentosos Amazônicos em um programa de triagem de antimicrobianos

Abstract

The rediscovery of bioactive compounds is a problem within natural product screening programs and the standardization of cultivation conditions that allow new actives to be obtained is critical in such programs. In this work, the impact of two solid media (rice and oats) and one liquid medium (Czapeck broth) and different cultivation conditions for antimicrobial actives were evaluated. Twelve filamentous fungi from Amazonian environments were used UV-Vis spectrophotometry estimated the complexity of the extracts produced. The antimicrobial activity of the extracts was evaluated against Escherichia coli, Salmonella sp. and Staphylococcus aureus. The solid media appeared to be more promising as they allowed to obtain a larger range of active metabolites. The oat medium provided a larger range of metabolites, but due to the great complexity of the extracts obtained, the separation procedures were considerably more complex than using rice. Taken together, the rice medium and the use of 39 days of fermentation proved to be a seemingly more promising cultivation condition than the liquid media usually employed in screening programs in Brazil. The extracts produced in this condition showed activity against at least two of the tested bacteria. The cultivation of Penicillium maximae (fungus isolated for the second time in Brazilian territory) in solid media yielded the production of active fractions against E. coli in bioautography.