L-asparaginase is an enzyme that plays a fundamental role in pharmaceutical and food industry. However, its greatest application has been in acute lymphoblastic leukemia (ALL) therapy. L-asparaginase acts by hydrolyzing free asparagine, and can be found in some eukaryotic and prokaryotic organisms. Such enzymes, worldwide used as antileukemics, comes from prokaryotics, and E. coli are their main representatives. However, these drugs cause immunological hypersensitivity to humans. Thus, filamentous fungi enable the viable substitution of prokaryotic L-asparaginase, as they are enzymes from eukaryotics, easy to grow, more compact and with high affinity. In addition, they can use extracellular enzymes, facilitating purification processes. In this context, the amazonic biome stands out for its biodiversity, its vast unexplored field and its great microbiological potential. This work aims to prospect the filaments of fungi affiliated to amazonian producers of extracellular L-asparaginase. During the study, 63 pieces of soil were isolated from the Research Support Center of the Middle Solimões in the city of Coari - Amazonas, using the serial dilution technique. After isolation, seventeen colonies were selected for fermentation production test in the modified Czapek Dox's Medium. In the first one, pre-fermentative stage, was got the mycelial mass, which was recovery by filtration and then submitted to the second stage, the fermentative one (culture medium supplemented with 0.07% bromothymol blue), to induce extracellular asparaginolytic activity. All isolated fungies were preserved by simple freezing with 20% glycerol solution. A qualitative evaluation of the enzymatic activity of L-asparaginase was observed from the color change of the yellow to blue culture medium in 8 of the 17 fungi tested, that Amazonian fungi can be a new source or explored for the enzymatic production of L - extracellular asparaginase.
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