We studied the fungal endophyte community of the leaves of Myracrodruon urundeuva in Brazil along with their potential to produce L-asparaginase. In total, 187 endophytes were isolated. The colonization rate of leaf fragments from caatinga (10.41 %) was lower than those from brejo de altitude (39.58 %). Sequences of ITS rDNA from all endophytes revealed relationships with Ascomycota (Botryosphaeriales, Chaetothyriales, Diaporthales, Eurotiales, Glomerellales, Hypocreales, and Pleosporales) and Basidiomycota (Polyporales). The most frequent endophytes were members of the genus Diaporthe. Talaromyces was an indicator genus for caatinga while Phyllosticta, Diaporthe, and Colletotrichum were for brejo de altitude. The composition of endophytic fungi in caatinga and brejo de altitude differed significantly, its richness and diversity (H' = 3.41) being significantly higher in brejo de altitude. Diaporthe sp. URM 7793 was the best producer of L-asparaginase (2.41 U/g), followed by Diaporthe sp. URM 7779 (2.00 U/g), Talaromyces sp. URM 7785 (1.91 U/g), and Diaporthe sp. URM 7792 (1.47 U/g). The composition of endophytic fungi assemblages is strongly influenced by the type of ecosystem. In its natural habitat, M. urundeuva harbors an important diversity of endophytes, which could be used to produce L-asparaginase.

Aims The aim of this study was to find new eukaryotic sources of the l‐asparaginase (l‐ASNase), since the prokaryotic sources of the enzyme are well‐reported as causing allergic hypersensitivity reactions in a significant number of patients. This report describes screening for l‐ASNase production by filamentous fungi isolated from the Brazilian Caatinga, and the optimization of fermentation parameters to increase fungal growth and improve yield in the production of l‐ASNase. Methods and Results Thirty‐two filamentous fungi were investigated in this study. When Aspergillus terreus strain S‐18 was cultured in a proline‐enriched medium, intracellular l‐ASNase was expressed in concurrence with reduced l‐glutaminase (l‐GLUase) and protease activities. Fermentation conditions were then optimized in a 5‐l bioreactor system to produce a maximum volumetric yield of 108 U total of l‐ASNase activity. Conclusions The work reported here represents the first attempt to produce l‐ASNase by filamentous fungi isolated from Brazil and offers a promising alternative eukaryotic source for l‐ASNase production. Significance and Impact of the study In order to minimize the side effects caused by bacterial l‐ASNase, the search of eukaryotic micro‐organism for l‐ASNase was carried out in fungi. This study demonstrates the diversity of filamentous fungi isolated from the Brazilian Caatinga Biome and the importance of knowledge of the microbial metabolism to obtain high concentrations of biotechnological products.

L-Asparaginase amidohydrolase (EC 3.5.1.1) has received significant attention owing to its clinical use in acute lymphoblastic leukemia treatment and non-clinical applications in the food industry to reduce acrylamide (toxic compound) formation during the frying of starchy foods. In this study, a sequential optimization strategy was used to determine the best culture conditions for L-asparaginase production from filamentous fungus Aspergillus terreus CCT 7693 by submerged fermentation. The cultural conditions were studied using a 3-level, central composite design of response surface methodology, and biomass and enzyme production were optimized separately. The highest amount of biomass (22.0 g·L⁻¹) was obtained with modified Czapek–Dox medium containing glucose (14 g·L⁻¹), L-proline (10 g·L⁻¹), and ammonium nitrate (2 g·L⁻¹) fermented at 37.2 °C and pH 8.56; for maximum enzyme production (13.50 U·g⁻¹), the best condition was modified Czapek–Dox medium containing glucose (2 g·L⁻¹), L-proline (10 g·L⁻¹), and inoculum concentration of 4.8 × 10⁸ espore·mL⁻¹ adjusted to pH 9.49 at 34.6 °C. The L-asparaginase production profile was studied in a 7 L bench-scale bioreactor and a final specific activity of 13.81 U·g⁻¹ was achieved, which represents an increase of 200% in relation to the initial non-optimized conditions.