Produção de L-Asparaginase e diversidade de fungos endofíticos de Mandevilla catimbauensis (Apocynaceae) do Parque Nacional do Vale do Catimbau

Abstract

The Caatinga, an exclusively Brazilian region, has 47 conservation units, among them, the Catimbau Valley National Park. The park is compound of numerous endemic species, including Mandevilla catimbauensis, a rare species belonging to the family Apocynaceae, which is classified as vulnerable to extinction. Endophytic fungi live inside the plants without causing them harm. Some endophytes have the potential to produce bioactive substances like the enzyme L-asparaginase. Lasparaginase is used to treatment various cancers in humans and other animals. It is also used in the food industry to reduce the levels of acrylamide in food. Researchers pursue for eukaryotic sources capable of producing L-asparaginase with lower side effects. The aim of this study was to estimate the diversity of endophytic fungi present in M. catimbauensis and to evaluate the biotechnological potential of these fungi in the production of L-asparaginase. A total of 66 isolates were obtained and the rate of colonization of the fragments was 11.78%. Phylogenetic analyzes using ITS and / or LSU sequences of rDNA revealed the presence of seven orders of the Ascomycota phylum. A total of 18 taxa were identified. The most commonly isolated endophytes were members of the genus Phyllosticta (45.10%). The curve of species accumulation did not reach the point of stabilization. A new species of the genus Phyllosticta was discovered, described and published as Phyllosticta catimbauensis. The production of L-asparaginase was studied by 20 isolates. A total of 14 fungi were efficient to produce the enzyme (0,48 U g-1 – 2,22 U g-1). The species P. catimbauensis exhibited significant capacity and was selected to perform a factorial design 23. The best enzymatic production was 2,25 U g-1, using 1,5 g of Lasparagine, pH 5 and 1,5 g inoculum . Subsequently, an experimental sequence was performed and a significant increase in L-asparaginase production of 3,50 U g-1 was obtained using 3,5 g of L-asparagine, pH 4,2 and 1 g of inoculum. This is the first study on the endophytic fungi of M. catimbauensis and also on the production of Lasparaginase by these fungi. This research may contribute to the knowledge of the fungal community present in M. catimbaunensis, besides helping future studies on the enzymatic production of these endophytes.