Produção de enzimas hidrolíticas por leveduras isoladas de solos de áreas preservadas em Roraima, Brasil

Abstract

The present work, as its objective, aims at assessing some biotechnological characteristics of yeasts isolated from soils of Maracá Ecological Station and Viruá National Park, in Roraima. The assays included hydrolysis of olive oil, gelatin, Tween 80, Carboximetylcellulose and soluble starch in order to assess the ability of strains to produce lipases, proteases, esterases, cellulases, and amylases respectively at 25ºC, 37ºC and 45ºC. It was assessed an average of 397 strains. Approximately 90% of the strains exhibited at least one enzymatic activity, and 30% two or more activities. Strains VR16, VR343, VR367, VR380, VR407, VR430, VR464 and VR474 showed expressive amylolytic activity. Cellulases production was more frequent at 37ºC, with 8,85% of positive yeast strains. On the other hand, only 2,71% of strains showed cellulolytic activity at 25ºC. The highest percentage of positive yeast was observed on assays for the production of esterases, over 70% of yeast strains demonstrated ability to produce the enzyme on assays carried out and, approximately 60% them showed strong esterases production. Proteolytic activity was observed on 6,49% of yeasts at 25ºC. The lipases production was observed on 26,98% of strains, being the best production indexes recorded by strains VR36, VR172 at 25°C and, VR408, VR475 and VR481 at 37ºC, which performed as excellent lipases producers. This study clearly revealed the potential of soil yeast strains to produce a wide range of hydrolytic extracellular enzymes biotechnologically interesting.