Perfil fenotípico, enzimático e antagônico de isolados de actinobactérias endofíticas do Cerrado

Abstract

The Brazilian savanna, denominated Cerrado is characterized by diverse typology of vegetation, with many of them used in folk medicine as an alternative form of health care, however, little studied scientifically. Plants can serve as a reservoir for various microorganisms that classified as endophytes can produce a multitude of metabolites, both primary and secondary. The entophytic actinobacteria are part of a target group of studies that seek new products of industrial interest as antibiotics, enzymes, antifungals, and other bioactive compounds. This work aimed to evaluate the phenotypic profile of actinobacteria isolated entophytic from the Cerrado, the ability to synthesize extracellular enzymes and active metabolites against species of Candida albicans, C. krusei, C. tropicalis, C. glabrata and C. parapsilosis isolated from the oral cavity of irradiated patients, with head and neck malignancies with a history of resistance or tolerance dose to commercials antifungals. Actinobacteria collection from Epidemiology and Biocontrol of Microorganisms Lab, Universidade Estadual de Montes Claros, were morphotyping regarding reproductive structures. The enzymatic characterization was evaluated through the amylolytic, cellulolytic, sterolytic, lipolytic, proteolytic and pectinolytic expressions. Twelve genera of actinobacteria were recognized Actinopolysora, Micromonospora, Terrabacter, Nocardia, Saccharopolyspora, Streptosporangium, Thermoactinomyces, Streptoalloteichus, Streptomyces, Streptoverticillium, Nocardioides, and Nocardiopsis. The metabolic extracts of 88% of actinobacteria strains presented more than 70% inhibitory action against at least one of the species of Candida spp. challenged. It was observed that the Starch-Nitrate-casein broth (SCN) showed to be better stimulating substrate in the biosynthesis process of antibiotic substances produced by actinobacteria. Five actinobacteria isolated were superior to the others, however with inhibition intensities dependent on the Candida species challenged. Related to the enzymatic activity, 94% expressed amylase, 88% lipase and gelatinase, 71% esterase, 59% cellulase, 24% caseinase and 6% pectinase.