Prospecção de actinobactérias do semiárido nordestino com potencial biotecnológico na produção de enzimas relacionadas à hidrólise de carboidratos

Abstract

Actinobacteria are a representative part of soil microorganisms. They are Gram-positive bacteria, filamentous and often branched. This group grows in extreme environments where they produce a range of biomolecules, including enzymes. In that sense, these bacteria represent an attractive biotechnological potential. Thus, the actinobacteria in this study were collected from the soil of a semi-arid region where abiotic conditions induce metabolic adaptations for complex polymer catalysis. The aim of this study was to isolate and characterize actinobacteria from the soil of the National Park of Ubajara to evaluate the enzymatic potential. The soil samples were collected between April and June 2018. These samples were prepared and then inoculated in a selective culture medium for the counting and chromogenic characterization of the colonies, which consisted of the observation of the aerial mycelium and the reverse mycelium of each isolated, as well as, the presence or absence of diffusive pigments in the medium. Thirty-nine strains were isolated, preferably with different cultural characteristics and are kept in adequate conditions at the (LAMAB) Laboratory of Environmental Microbiology of the Department of Biology at the Federal University of Ceará. The catalytic action of the enzymes: cellulase, amylase, xylanase and pectinase was studied by measuring the Enzyme Index (IE), a semi-quantitative method, corresponding to the ratio, division between the diameter in millimeters of the catalysis halo and the diameter in millimeters of the colony of each strain. The results of this work showed that the strains of the genus Streptomyces UBJ 25 (IE = 5.6), UBJ 17 (IE = 8.21) UBJ 20 (IE = 11.33) and UBJ 38 (IE = 8.05) presented the greater amylolytic, cellulolytic, pectinolytic and xylanolitic activity, respectively, possessing the biotechnological potential, especially with regard to the exploration of enzymes related to the degradation of carbohydrate polymers.