As Ciências Biológicas nas Dimensões Humanista, Crítica e Reflexiva

Bioprospection of microorganisms at unexplored sites, such as insect microbiota, is important for obtaining both microorganisms and enzymes, with potential biotechnological applications. Glucosidases are enzymes that catalyze the hydrolysis of glycosidic bonds of oligosaccharides and glycoconjugates, used in the production of biofuels and the food industry. The objective of this work was the evaluation of extracellular αand β-glucosidases produced by endosymbiont yeasts from the gut of Broca-da-Andiroba larvae (Hypsipyla spp.). The isolates were screened for the production of extracellular glucosidase on solid medium in the presence Esculin 0.1%. The effect of pH (4.0-9.0) and temperature (25oC-70oC) on glucosidase activity were analyzed using p-nitrophenyl-glucopyranoside as substrate. All yeasts had extracellular enzymatic activity: β-glucosidases showed an alkaline pH optimum and temperature ~40oC, highlighting the strain Candida jaroonii (M2). α-glucosidases presented a pH optimum rangeing from acid to alkaline and temperature >40oC, highlighting the strains Candida tropicalis (M4) and Candida jaroonii (M2) with activity at 70°C, 76 mU.ml-1 and 91 mU.ml-1, respectively. Higher activities in alkaline pH can provide a broader application of this class of enzymes. The present work is pioneer in the study of yeast glucosidases of Hypsipyla spp. microbiota.