Triagem de fungos endofíticos de Moringa oleífera produtores de asparaginase e amilase

Abstract

Endophytic fungi are microorganisms that inhabit plant tissues and are recognized for their potential in the production of important products of biotechnological interest. They can be considered important sources of enzymes of commercial interest, such as amylase, which acts on the degradation of starch, and asparaginase of great importance in the medical / pharmacological area for the control / treatment of tumor cells. In this context, the work aimed to prospect for the enzyme asparaginase and amylase produced by endophytic fungi isolated from the medicinal plant Moringa oleifera. For the screening of asparaginase, a specific medium containing L-asparagine (10g / L) was used as a substrate, in addition to glucose, KH2PO4 (1.52g / L), KCl (0.52g / L), MgSO4 .7H2O ( 0.26g / L), CuNO3 .3H2O (0.001g / L), ZnSO4 .7H2O (0.001g / L), FeSO4 .7H2O (0.001g / L), agar (20g / L) and the red phenol indicator ( 0.009%) with pH 6.8 and 8.2 turning range. The formation of a red zone around the colony indicated the production capacity of L-asparaginase by the fungus. For the screening of amylase-producing fungi, a specific medium containing NaCl (0.26g / L), yeast extract (0.4g / L), KH2PO4 (0.5g / L), MgSO4.7H2O (0 , 2g / L), Agar (15g / L) plus 0.2% soluble starch. After 96 hours of incubation at room temperature, the plates were developed with KI (1%). The enzymatic activity was evaluated through the halo formed which indicates the degradation of the substrate. The results for both enzymes were expressed using an enzyme index. For the screening of asparaginase, 36 endophytes were analyzed, where 1 did not show enzyme activity (2.77%), 3 (8.33%) showed weak activity, 26 (72.22%) moderate and 6 (16.68%) high asparaginase activity. To prospect for amylase, 26 endophytic fungi were studied, with 96% showing intermediate activity and 4% high amylolytic activity. The results were promising, demonstrating the production of the enzymes amylase and asparaginase by a large percentage of the isolated fungi, although at different levels, it can be considered a niche of microorganisms with great biotechnological potential to be explored.