Filamentous Fungi Producing <span style="font-variant: small-caps">l</span>-Asparaginase with Low Glutaminase Activity Isolated from Brazilian Savanna Soil

Abstract

l-asparaginase is an enzyme used as treatment for acute lymphoblastic leukemia (ALL) due to its ability to hydrolyze l-asparagine, an essential amino acid synthesized by normal cells unlike neoplastic cells. The adverse effects of l-asparaginase formulations are associated with its glutaminase activity and bacterial origin; therefore, it is important to find new sources of l-asparaginase-producing eukaryotic microorganisms with low glutaminase activity. This work evaluated the biotechnological potential of filamentous fungi isolated from Brazilian Savanna soil and plants for l-asparaginase production. Thirty-nine isolates were screened for enzyme production using the plate assay, followed by measuring enzymatic activity in cells after submerged fermentation. The variables influencing l-asparaginase production were evaluated using Plackett–Burman design. Cell disruption methods were evaluated for l-asparaginase release. Penicillium sizovae 2DSST1 and Fusarium proliferatum DCFS10 showed the highest l-asparaginase activity levels and the lowest glutaminase activity levels. Penicillium sizovae l-asparaginase was repressed by carbon sources, whereas higher carbon concentrations enhanced l-asparaginase by F. proliferatum. Maximum enzyme productivity, specific enzyme yield and the biomass conversion factor in the enzyme increased after Plackett–Burman design. Freeze-grinding released 5-fold more l-asparaginase from cells than sonication. This study shows two species, which have not yet been reported, as sources of l-asparaginase with possible reduced immunogenicity for ALL therapy.

Keywords

• l-asparaginase%22%2C%22default_operator%22%3A%22AND%22%7D%7D%7D"> <span style="font-variant: small-caps">l</span>-asparaginase
• filamentous fungi
• <i>Penicillium</i>
• <i>Fusarium fujikuroi</i> species complex
• acute lymphoblastic leukemia
• Plackett–Burman design