INVESTIGADORES
CASTRILLO Maria lorena
congresos y reuniones científicas
Título:
SELECTION OF CARBON AND NITROGEN SOURCES FOR ENHANCING THE SECRETION OF MYCOLYTIC ENZYMES OF ESCOVOPSIS IN SUBMERGED FERMENTATION
Autor/es:
BARENGO, MP; AMERIO, NS; BICH, GA; ZAPATA, PD; CASTRILLO, ML
Lugar:
Versión en línea
Reunión:
Simposio; Anais do I Simpósio de Microbiologia de Rondônia: Saúde, Ambiente e Inovação.; 2021
Resumen:
Translator Introduction: In the province of Misiones (Argentina), one of the major pests affecting the forestry sector are leaf-cutter ants of the genera Atta and Acromyrmex. Their forage activity consists of cutting and transporting to nest fresh plant material, on which the fungus Leucoagaricus gongylophorus (Basidiomycota: Agaricales) grows, which is their main source of food. One the other hand, fungi of the genus Escovopsis (Ascomycota: Hipocreales) are considered specialist parasites of L. gongylophorus. These mycoparasites secrete extracellular mycolytic enzymes, mainly chitinases, glucanases, and proteases, which are capable of hydrolyzing the cell walls components of their host. Therefore, Escovopsis is a potential indirect biocontrol agent of leaf-cutter ants, and an effective way for its biotechnological application is to induce its mycolytic activity.Objective: In this study, the objective was to select carbon and nitrogen sources, which promote the greater secretion of mycolytic enzymes in a strain of Escovopsis native from Misiones.Methods: We used a promising strain of Escovopsis, previously identified and selected by our working group. Assays in submerged fermentation were performed. A factorial design of two and four levels, using different carbon sources (cell walls of Fusarium sp. and L. gongylophorus) and nitrogen sources (yeast extract, urea, ammonium sulfate and the Mandels nitrogenous complex) were performed.The Escovopsis capacity to secrete mycolytic enzymes was quantitatively assayed. Proteolytic activity though the azocasein method, and β-1,3-glucanase and chitinase activities by the dinitrosalicylic acid method were assayed.All the tests were done in duplicate and data were processed though the statistical software InfoStat 2018. To evaluate and select variables that had a significant effect on enzyme activity Tukey´s test wasused. Analysis of variance (ANOVA) and a test of difference between means were performed, with confidence level of 95.0%.Results: Regarding to carbon sources, a significant effect for the three analyzed enzymes (p <0.05) was observed; and the media containing cell walls of L. gongylophorus showed the highest activity.Regarding the nitrogen sources, the highest enzymatic activity in the media that containing the Mandels nitrogenous complex was observed, with a significant effect for β-1,3-glucanases and chitinases (p <0.05). Furthermore, the media containing urea and ammonium sulfate did not show activity for any of the analyzed enzymes.Particularly, for chitinases an interaction between the two studied factors was observed; and the tests that contained jointly, cell walls of L. gongylophorus and Mandels showed a significantly higher activity than the other assays (p <0.05).Conclusion: The factorial design used allowed us to select the variables that presented statistically significant effects on the enzymatic secretion of Escovopsis. It was determined that enzymatic secretion is promoted when liquid fermentation is carried out using the cell walls of L. gongylophorus as a carbon source and the Mandels complex as a nitrogen source. Subsequently, each of these factors will be optimized.